Intercooler Fan - Install ?

JT93SC

Registered User
I followed the install instructions from 1 of the threads here on how to wire up my intercooler fan using a switch and a 30 amp relay. I finished the install and did a triple check on my wiring, but the fan won't come on. I guess it's possible I have a bum relay. (Fan works when I connect it straight to the battery) My question is - why is the relay necessary? Wouldn't it be OK just to run power to the fan then to a 10amp fuse - to the switch and then ground?

Thks - JT
 
The whole point of a relay is to keep high amounts of power from having to flow through the actual switch. This is not very efficient and can lead to the switch overheatng, or melting, or catching fire.

I think this is part of the problem with the SC headlight system. All the power runs right through the switch in the dash and burs up the switch.. Try a different relay, and make sure you have it wired correctly.
 
You would be going though a lot of switches as that many amp`s will kill the switch. Not all relays are set up in the same order. Try to wire it to to the letters in the instuctions your following. I don`t have that info handy. Will someone post the info he needs on a simple relay hook up?
 
Relay info

Thanks for the info on the relay's. I wasn't thinking that there would be an overheating issue with the switch. I'll verify which type relay I bought and go over the wiring again. I used a Tap connector off the Red / light green wire that also crimps into the wire back to the Relay and I'm a little suspect of this connection.
I was hooking this up Sunday morning before I went to the track, and I guess I got a little frustrated when it wouldn't work... Nothing a little electrical tape wouldn't fix so I was able to at least have the fan working when I made my runs.
Ohhhh yea, best run - 14.18 @ 99.8 mph... (slowly creeping up on 13's)

Thks JT
 
That site rox...lots of cool little projects you can do with relays....if only I had the time:rolleyes: .

These guys have come through for me in a pich more times. Relays and alarm systems don`t incorporate relays any more so all most every funtion needs a relay. Nice times there JT.
 
Probably have the relay wired up wrong.

You can test the function of the relay with an ohm meter and your battery. Just sitting there the relay should show show 0 ohms or closed between the terminals 30 and 87a. If you check between 30 and 87 it'll be open, infinite resistance.

Drop 12v across 85 and 86 and that should create a magnetic field to pull the relay. You should hear or feel a click and checking 30 and 87A you'll now see its open with infinite resistance and now 0 resistance and closed on 30 and 87.

If it doesn't work like that then the relay is bad. Now that's a standard relay as well. IF it's non-standard, it could have some of the pins switched around. But if it's got the same number of pins and it's a SPST relay, you should be able to check the various pins to figure out which ones work which way.
 
Relay Test

Thanks for the test instructions. I'll dig my Ohm Meter out and test the relay tonight...

JT
 
Fan works now

We'll thanks for everyone's help and suggestions. I now have a better understanding on how a relay works.
Turns out my problem was the tap connector. I used 12gauge wire for all my connections to the relay, fan and switch. I then tried to use a 12 gauge tap connector for connecting into the red /green wire. The problem was I had a 12 gauge wire on 1 side of the connector and the red/green wire was 14 or 16 gauge. When I closed the connector the metal tapped into the thicker wire but didn't go right through the cover on the thinner gauged wire. I hooked up a 14 gauge tap connector and the fan fired right up.

JT
 
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