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Location:
Sydney
Registered:
July 2002
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Burning wires
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Thu, 16 October 2003 23:41
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I'm not electrical minded at all  , but have wired my car 
My main DC16 thermo fan works great, never had a problem with it (except for the relays and switches etc. different story).
My other fans consist of 2 x CD sized ones on the side of the radiator and 1 x 10inch one in between the radiator and the intercooler.
These other 3 fans I've tried to wire off the one relay, which resulted in the large wire from the batery to the relay (about 15cm long, and pretty thick) melting, and some of the small wires to the fans (I used cheapy stereo wires) have burnt off the relay completely.
Now if I only put one of the fans on the relay and put a new thick power wire to the relay it still burnt off the relay.
Are my wires to the fan too thin? (I've got some thicker ones but don't want to do it if its not going to make a difference)
Is my relay busted?
Is my battery/charge system stuffed? (everything else works great)
I've got a nice multimeter that I'm learning to use - used it in wiring the engine, but I'm still not sure what it all means I just kept twisting the knob till something I could understand came up on the readout.
The large DC fan is adequate for cooling, but having 4 thermo fans is just cool  . Plus when I put my intercooler back in I want more airflow to the radiator.
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Location:
Northwestern Sydney
Registered:
August 2002
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Re: Burning wires
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Thu, 16 October 2003 23:46
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Possibly a bad earth in that circuit.
check your earth connections an beef up the wiring to earth
I Just had a similar problem.
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Location:
Sydney
Registered:
July 2002
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Re: Burning wires
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Thu, 16 October 2003 23:50
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The bolt that the earth from the battery to chassy is nearby, I might look at putting it on that bolt instead of the back of the relay (the screw that holds the relay to the chassy).
Thanks mate 
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Location:
Northwestern Sydney
Registered:
August 2002
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Re: Burning wires
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Fri, 17 October 2003 00:04
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Could be your problem if your using the normal plastic case relays bolted through paintwork your ring connection may not be contactiong any metal or very little (as was my problem) you could use a separate bolt and make sure that the bolt head is touching the ring connection (clamping)
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Location:
Sydney
Registered:
July 2002
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Re: Burning wires
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Fri, 17 October 2003 00:08
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Thats exactly what I'm doing.
Ok I'll change it this weekend and see if it improves.
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Location:
Epping, Sydney
Registered:
April 2003
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Re: Burning wires
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Fri, 17 October 2003 00:09
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| Quote: |
I just kept twisting the knob till something I could understand came up on the readout.
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lol, I AM NOT ALONE! 
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Burning wires
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Fri, 17 October 2003 00:11
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i'd be seriously looking at setting up individual circuits for each.... also get some decent wire, likr the 15 or 20amp stuff from jaycar (figure 8 autop or something like that) is only a couple of $/m. chances are you've fried the relay.. grab some Bosch ones from the wreckers.... lots of them in things like Vl commondores etc.
is the relay connected up properly? are there any shorts in the power circuit? are the fans ok? melting wires (ime) has been due to a wires insulation being cut, or some other cause resulting in a short circuit to ground.... 100+amps thru speaker wire is not good.
if you have the thick speaker wire, then that might be ok. you'd want the copper part to be maybe 1-1.5mm diamter as a guess..
pm me if you want any more help
Cya, Stewart
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Location:
Sydney
Registered:
July 2002
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Re: Burning wires
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Fri, 17 October 2003 00:15
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Thanks Stewart. What I might do is pull it all out and re-do the lot. Put the thicker speaker wire in to all 3 fans, get a really good earth, replace the relay.
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Location:
Canberra
Registered:
August 2003
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Re: Burning wires
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Fri, 17 October 2003 02:50
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Speaker wire is engineered for high response, low(ish) current, AC situations - Don't use it for the fans these are high current DC which is not quite right... I used to make that sort of mistake, even your big ass ofc speaker cable is no good for drawing high loads!!
I could go into large amounts of details...as to figures, the faraday effect and how the cable is desgined differently (lots of small wires, opposed to a few bigger ones) etc, or you could just take my word for it.
proper cable is cheaper anyway...
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Location:
Perth
Registered:
September 2002
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Re: Burning wires
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Fri, 17 October 2003 02:57
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if the relay clicks then its working properly, but they do have a current limit
u should prolly have one for the big fan, and one for the rest
make sure the earth wire on the fans and the relay is as big as the power wire going to it
when grounding through a bolt hole, scratch off some of the paint so that the wire/connector is contacted with bare metal
remember, paint doesnt conduct
if you want to test the current that all the fans are drawing, put the black lead in the COM hole and the red in the 10A hole (this is usually the case, but not always), and set the dial to 10A
then place the DMM (digi multimeter) in SERIES with the power cable going to the fans, with the red lead on the battery and the black lead on the wires going to the fans/relay, depending on the setup
if this works u should know how much current the fans are drawing, and buy some cable to handle this
dont use speaker wire, its not designed to take it
buy some proper auto wire (5m rolls, get a red, a black, and prolly a blue or green to distinguish the different purposes
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I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
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Re: Burning wires
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Fri, 17 October 2003 07:28
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Why the fuck is every electrical problem talked about on this forum automatically diagnosed as being a bad earth
Anyway what type of relay are you using? Can you get a photo of the relay? Preferably the side which shows the internal circuit so I can talk you through the wiring?
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Location:
Perth
Registered:
September 2002
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Re: Burning wires
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Fri, 17 October 2003 07:50
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| Cool1 wrote on Fri, 17 October 2003 15:28 |
Why the fuck is every electrical problem talked about on this forum automatically diagnosed as being a bad earth
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coz most ppl dont realise that any current that flows in the positive side, must get back to the body via the earth, and hence they just chuck a small one on, barely touching the bodywork
anyway, i'd say pete is using the standard davies craig relay, similar to bosch ones (ie the numbers 30, 85,86,87)
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Toymods Social Secretary
Location:
Sydney
Registered:
July 2002
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Re: Burning wires
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Fri, 17 October 2003 09:01
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Pete,
if you car is running, give me a call and perhaps you can drop by after i finish work on saturday or sunday, i'll sort the problem out.
My thoughts are though, that even if the wires are small, it still takes a fair whack of current to burn them out!
What i would be doing, first of all is this:
on each fan individually to test them, and if you are blowing fuses there, then there is something wrong with your fan.
I had a similar thing happen on my old AE92, turned out being that the fan was pooped!
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Location:
sydney
Registered:
March 2003
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Toymods Social Secretary
Location:
Sydney
Registered:
July 2002
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Re: Burning wires
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Fri, 17 October 2003 14:18
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i find electric motors to be quite interesting devices really....
say for instance our little 10A thermo fan here... when running it draws around 10A. However, for that motor to "kick over" for the first time it requires a massive rush of current... which under "no-load" conditions on a typical electric motor is around 3-4 times the rated current (note: a fan on a motor is a load )
Now if that same motor were to start up under load, say with a fand attached to it, it can draw up to 10 and sometimes 20 times its rated operating current!
/end electric motors lesson 1.
p.s. Don't worry, that instantaneous start-up current is so short lived that relays have no problems with it, and nor would a fuse in most cases. Much like sideshow has mentioned 
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Location:
Menai area of Sydney
Registered:
June 2003
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Re: Burning wires
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Sat, 18 October 2003 00:19
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You said early on that if you connect only one fan, the wires still burn out. Does this happen with each of the three fans or only one. Maybe you have a really good earth ... only problem is it's inside one of the fans.  If it happens with each of the fans you've probably got a really good earth inside your relay. Do each of the fans work properly when connected directly to the battery ... with some decent wire ?
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Location:
NSW
Registered:
October 2003
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Re: Burning wires
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Sat, 18 October 2003 02:28
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| Cool1 wrote on Fri, 17 October 2003 17:28 |
Why the fuck is every electrical problem talked about on this forum automatically diagnosed as being a bad earth
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Perhaps because that is one of the simplest and most obvious things to fix that is associated with burning wires...
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I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
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Re: Burning wires
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Sat, 18 October 2003 02:54
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| ta23 wrote on Sat, 18 October 2003 12:28 |
| Cool1 wrote on Fri, 17 October 2003 17:28 |
Why the fuck is every electrical problem talked about on this forum automatically diagnosed as being a bad earth
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Perhaps because that is one of the simplest and most obvious things to fix that is associated with burning wires...
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Ok now explain why having a bad earth would cause wires to burn out?
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Toymods Social Secretary
Location:
Sydney
Registered:
July 2002
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Re: Burning wires
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Sat, 18 October 2003 06:52
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if an earth wire is say, perhaps grossly undersized (i have seen this first hand on more than one occasion!)
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Location:
NSW
Registered:
October 2003
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Location:
Menai area of Sydney
Registered:
June 2003
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I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
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Re: Burning wires
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Sat, 18 October 2003 08:32
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| ta23 wrote on Sat, 18 October 2003 17:04 |
As he has said -
| THE WITZL wrote on Sat, 18 October 2003 16:52 |
if an earth wire is say, perhaps grossly undersized (i have seen this first hand on more than one occasion!)
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Also I have had experiences with burnt wires on my Haltech EMS, when I contacted the guy that wired up my EMS for me he pointed out that it is a bad earth, soon as earth fixed, no more burnt wires. Is this good enough for you or do you know better cool1?
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No thats not good enough, it doesnt explain a damm thing! Maybe you should re-read the guys original post! There is no way his problem is caused by a bad earth!
I think you should go back to college and redo your electronics course 
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I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
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Re: Burning wires
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Sat, 18 October 2003 14:49
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| HKSPete wrote on Fri, 17 October 2003 09:41 |
I'm not electrical minded at all , but have wired my car
My main DC16 thermo fan works great, never had a problem with it (except for the relays and switches etc. different story).
My other fans consist of 2 x CD sized ones on the side of the radiator and 1 x 10inch one in between the radiator and the intercooler.
These other 3 fans I've tried to wire off the one relay, which resulted in the large wire from the batery to the relay (about 15cm long, and pretty thick) melting, and some of the small wires to the fans (I used cheapy stereo wires) have burnt off the relay completely.
Now if I only put one of the fans on the relay and put a new thick power wire to the relay it still burnt off the relay.
Are my wires to the fan too thin? (I've got some thicker ones but don't want to do it if its not going to make a difference)
Is my relay busted?
Is my battery/charge system stuffed? (everything else works great)
I've got a nice multimeter that I'm learning to use - used it in wiring the engine, but I'm still not sure what it all means I just kept twisting the knob till something I could understand came up on the readout.
The large DC fan is adequate for cooling, but having 4 thermo fans is just cool . Plus when I put my intercooler back in I want more airflow to the radiator.
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What type of fans are you using? They dont happen to have shunt diodes in them do they
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Location:
NSW
Registered:
October 2003
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Re: Burning wires
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Sun, 19 October 2003 03:12
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| Cool1 wrote on Sun, 19 October 2003 00:49 |
What type of fans are you using? They dont happen to have shunt diodes in them do they
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I have a rather standard 3TGTE, so therefore I only have the standard fan and no aftermarket fans.
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I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
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Re: Burning wires
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Sun, 19 October 2003 04:48
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| ta23 wrote on Sun, 19 October 2003 13:12 |
| Cool1 wrote on Sun, 19 October 2003 00:49 |
What type of fans are you using? They dont happen to have shunt diodes in them do they
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I have a rather standard 3TGTE, so therefore I only have the standard fan and no aftermarket fans.
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I was asking hkspete
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Location:
Menai area of Sydney
Registered:
June 2003
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Re: Burning wires
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Sun, 19 October 2003 05:15
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Perhaps people should learn to distinguish between an "earthing" problem and a "shorting" problem. An earthing problem means less current gets to earth whereas a shorting problem means too much current gets to earth. Before people throw up suggestions for resolving problems they should do some elementary diagnosis of what the problem is and if they don't know the solution DON'T provide one ... by all means post an expression of interest in the answer and then wait till someone who knows what they are doing responds. In this case, the problem is more likely to be a "shorting" or overloading problem which can easily be linked to consequences such as burned out wiring.
Of all the suggestions that have been offered, there has been no response from HKSPete as to what he has tried or achieved. Perhaps we should wait to see his results before we continue these bullshit arguments back and forth. It would be nice to know that HKSPete has managed to resolve his problem and the manner in which he did it. 
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Toymods Social Secretary
Location:
Sydney
Registered:
July 2002
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Re: Burning wires
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Sun, 19 October 2003 06:58
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stick to the topic, lets not get personal here!
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Location:
sydney
Registered:
March 2003
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Re: Burning wires
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Sun, 19 October 2003 07:12
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yes
the way things are going the car will never be fixed
just take it to auto electrician
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Location:
Sydney
Registered:
July 2002
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Re: Burning wires
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Sun, 19 October 2003 08:59
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Fuck me, wasn't expecting a big debate/argument about this.
Sorry for this, but I havn't looked at the car yet! As I said in my original post the car is working, but it burns out the wires when I connect any of the extra fans.
I'll get stuck into it soon. I've gotta get under it to change my oil before track day wednesday so could do the re-wiring while under there.
Sideshow: Reason for 4 thermos is that the MA70s come out with 3 thermos STOCK + an engine fan. I've swapped the engine fan for a LARGE Davies Craig DC16 (16inch very heavy duty). I want the extra fans as I want to put an intercooler infront of my radiator and MA70s are notorious for having very bad underbonet ventilation. This is even worse when instead of a thin 7M that alows air to flow around it theres a big FAT 1UZ. Thats why I want these other thermos to work as it was designed. In saying this, its not going through the standard wiring anymore, which is whats causing my problem.
Cool1: The 3 thermo fans I'm trying to get running are the stock CD sized ones on the side of the radiator, and the (also stock) larger chunky fan between radiator and intercooler.
Witzl: I only read it all now (Sunday night) otherwise I would've dropped in and you could have a quick look. I can wait till sunday's mega cruise. Shouldn't need to spend more than 10 mins on it, so won't take up too much of your time.
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Location:
Sydney
Registered:
July 2002
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Re: Burning wires
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Sun, 19 October 2003 09:02
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| sideshow wrote on Sun, 19 October 2003 17:12 |
just take it to auto electrician
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Know any good ones? Just kidding Still need to find a time when you can look at my cruise control.
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Location:
sydney
Registered:
March 2003
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Re: Burning wires
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Sun, 19 October 2003 09:44
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can u run a normal plastic factory blade fan
i prefer to run these if possible
losing 5 hp is nothing compared to how much better they cool
i have come across where this vl with rb26 in it was running twin thermos
he went back to std clutch fan with a correctly fitted shroud
engine ran much cooler
this engine has over 400 hp at the wheels
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Location:
Menai area of Sydney
Registered:
June 2003
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Re: Burning wires
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Sun, 19 October 2003 11:14
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Just an aside that may be stating the obvious but may be relevant ... when you wire up the fan between the radiator and intercooler, make sure it is blowing through the radiator and not trying to suck against the others as well as against the air pressure from the moving vehicle - and vice versa for those on the engine side of the radiator)
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Location:
Yowie Bay, Sydney
Registered:
June 2002
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Re: Burning wires
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Sun, 19 October 2003 12:26
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you 2 guys are fucked
dont u know its because the battery has too much power
all u need to do is get one of those batteries with the smaller terminals, problem solved
now to save time, that was sarcasm, y dont u both just stop embarrassing yourselves??
personally i cant see it being the earth, if the earth had a high resistance, it would fry the earth wire not the + wire
and it has nothin to do with the size of the earth to the relay, all that does is switch the contacts inside
the earth for the fan should go direct to the chassis or the - terminal
also pete, i'd be running a single fuse and relay for each of them, but if 3 are the factory ones (i think thats what u said) shouldn't they have their own factory wiring/fuses/relays already??
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Location:
sydney
Registered:
March 2003
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I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
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Re: Burning wires
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Sun, 19 October 2003 12:44
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| sideshow wrote on Sun, 19 October 2003 22:41 |
just to make a point
i wired up a car the other day
guy had not tightened earth strap bolt on the gbox all the way dont
bolt was only on 3 threads
while cranking the earth strap got hot and smoke sort of started
when hi amperage gettin used then i would asume this was a bad earth and made the earth wire get hot
this isnt theory or might not be true
but it did happen to me
so a bad earth can cause hot wires when load is hi like when cranking
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It sure can! Normally the end with the loose connection will get hot first and then disapate the heat along the rest of the wiring.
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Location:
Sydney
Registered:
July 2002
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Re: Burning wires
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Sun, 19 October 2003 23:17
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Reason why I'm not running the factory wiring is because I'm switching it with a non-factory ECU input.
Yes I'm running the fans the right way! I make sure I check it every time I wire them up.
Sideshow, the DC thermo fan I've got sits within the original MA70 shroud and pumps a lot of air. I have NO problem at all with this fan, it is not the issue here at all.
With the relays being busted, I've swapped the relay with the one from the davies craig fan and it still works fine, so I've eliminated that.
With running 1 fan per relay/wiring. Last time I wired it up I only wired up the medium-sized fan in between the radiator and intercooler spot (no intercooler at the moment), and it still burnt out.
Extra info: There was also wires burnt on the contact to the relay. They were both + and - wires that were burnt black (and some burnt so bad it tore the solder out and fell off the relay). The - wire from the relay to the chassy has never burnt, but I still havn't checked the connection to the chassy.
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Location:
Sydney
Registered:
July 2002
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Re: Burning wires
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Sun, 19 October 2003 23:19
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Also, the wires from the two CD sized fans were also black at the relay, so please don't say "Found your problem its the medium size fan, thats whats blowing the wiring for the other two".
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Location:
Sydney
Registered:
August 2002
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Re: Burning wires
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Mon, 20 October 2003 01:21
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Talking about bad earths, i had a problem on my corolla with one of the earths that was connected onto the engine block above the alternator.
After changing the motor in my AE82 we only connected up 1 earth. the small wire goes from strut tower to engine block ( above alternator ) the car use to be really hard to start, after a few days of heavy driving the wire just burst into flames.. lol's
So yeah, id say it's an earth problem
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Toymods Social Secretary
Location:
Sydney
Registered:
July 2002
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Re: Burning wires
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Mon, 20 October 2003 06:50
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ok.. anymore bitch fighting in this thread and ill get Danny in here! And you won't like it when he gets involved!
Now please, lets stick to the topic.
If you want to whinge, go to the outhouse threads.
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Location:
Menai area of Sydney
Registered:
June 2003
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Re: Burning wires
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Mon, 20 October 2003 13:54
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Have you tested the two CD fans without the centre one connected yet ? If you can relate which wires get burned to Witzl's diagram it would help us understand what's happening a bit better. Can you say which + and - wires got burned on that diagram with the middle fan ? Also, I presume the CD fans are connected to the relay at the same spot as the middle fan - could their wires have been affected by heat from the middle fan's wire ?
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Get a new relay, get some proper wire and connect one fan at a time until you get (or don't get) a problem. Basic electrical troubleshooting procedures should sort this out in 15 minutes. 