aftermarket fan wiring gettin hot

[SuperHO]

so i've got an aftermarket fan pulling air through the radiator...i've got 12 guage wire (fused) from the battery to a switch in the dash to the fan, which is grounded to a crossover tube support bracket bolt. after sitting in traffic and firing up the fan for about 3 minutes, i can smell melting insulation and the switch gets alarmingly hot. the insulation on the connectors at the switch is rather melted...wrong switch or what?

 

[intimdatr]

since you running the power through the switch from the battery to the fan and im guessing the fan pulls any where from 50 to 250 amps, your gonna need a pretty hefty switch. id recommend a bigger switch and if possible a better way to wire it. I.E. the switch going to a relay that then turns the fan on. just my two cents.

 

[turbosho]

what you need is a relay, install a standard bosch style relay similar to http://www.amazon.com/IMC-Audio-Rel..._1?ie=UTF8&s=automotive&qid=1304120436&sr=8-1

obviously you dont need 10 of them, but if you have 2 fans run two relays.

i stole this from the internet but basically this is what you want

 

[turbosho]

also if you melted that switch you should replace it.

 

[SuperHO]

thanks!

 

[SHOtime2511]

Can I ask why you have and aftermarket fan on (I assume) your gen 2 SHO?

 

[whiteman_01]

Yup, you need a relay BEFORE the switch starts on fire. Ask me how i know...... i was young then.

 

[SuperHO]

the factory fan motor decided to commit suicide a while back, and in the process melted the wiring harness leading up to it. considering i was 50 miles from home when this happened during construction season, i figured being without a fan was not the best idea.

 

[SHOtime2511]

the factory fan motor decided to commit suicide a while back, and in the process melted the wiring harness leading up to it. considering i was 50 miles from home when this happened during construction season, i figured being without a fan was not the best idea.

When your in a tight spot you gotta do whatcha gotta do.
I'd try to find a factory fan and rewire that back in.
The SHO factory fan is about as good as they get.
In fact there is a guy over in Orlando with an 9 second 2JZ powered 280Z that uses a SHO fan.

 

[Off Road SHO]

In fact there is a guy over in Orlando with an 9 second 2JZ powered 280Z that uses a SHO fan.

Now that you mention it, a few buggy drivers that I know, some with SHO power, two with Chebbie LS-sumthins in their buggies use SHO fans. They move a lot of air and are not too noisey doing it. Lee Finke ran a stock SHO radiator and fan on his Class 1 SHO powered car in the Baja 1000.

Tom

 

[SuperHO]

unfortunately, SHOs are few and far between at boneyards around here. i'd need to get at least a foot of the harness as well. when the fan motor siezed up, it kept trying, heated up the factory harness and fused it together. though i guess i could just rebuild the melted sections with store-bought wire...

 

[gmorrell]

The factory fan wiring is conservatively good for a 30A fan load, the only weak point seems to be the fan relay and PCB traces in the IRCM, but this can be fixed by carefully scraping the PCB traces down to bare Copper and soldering some solid Copper wire along the traces to beef them up - done this a few times.

If you decide to fix the factory fan wiring, use no less than 10 gauge stranded Copper, use uninsulated crimp sleeves, solder it after crimping and heat shrink or otherwise insulate the connection. Crimping alone is not sufficient for this gauge wire and current draw, and it's about impossible to make a gas-tight crimp on old wire that's built up some corrosion and started to work-harden - use some good rosin flux and solder it.

It wouldn't hurt to add a hefty in-line fuse to prevent a future meltdown.

If you want a dash fan switch, find the HEDF trigger wire from EEC to the IRCM and simply take it to ground.