IRCM shot, car is hot, need to replace relay! Please help!

[tmielnichuk]

Hi Everyone,

I have been having problems with my 89 MTX SHO overheating recently. I have replaced BOTH temp sensors and thermostat. I tested the IRCM as per instructions I found here on the forum, and I am led to believe it is the problem. here is what I found:

Direct connect the fan to battery... AOK

I get power at pins 1 and 2 on the IRCM

I grounded pin 14 but the relay DID NOT energize and activate the fan.

I am assuming that since the grounding of pin 14 failed to activate the fan then the relay inside is "dead".

My question is this...

Can I simply wire in a new relay (cheap) or do I have to replace the entire IRCM (expensive)

I am fairly handy with a soldering iron and feel comfortable around electrical stuff, but have no idea what kind of relay to purchase and how to wire it up correctly (read safely)!

Can anyone tell me exactly what kind of relay to buy, and exactly how to wire it up? I hope that I am not asking too much but I really can't afford to replace the whole damn IRCM.

Thanks guys!

[email protected]

 

[projectSHO89]

Make sure you have the ignition switched to RUN when grounding pin 14, it is a pre-requisite in that test.

Yes, you can splice a relay into the harness. All you will need is a generic relay and harness from AutoZone (probably) and to splice it in using crimp-on splice connectors.

Applicable to the 89. Use caution for any other year. Consult the schematics!

Connect the relay high side to pin 24, low side to pin 14. The other two connections can be reversed, it won't matter. Common to Pin 1 or 2, and the NO (Normally open) contact to pin 3/4.

Use a heavy (10-12) ga wire for the last two connections.

It will look a bit odd, but you should be able to do it for under 10 bucks.

Seal all your connections after testing the circuit to make sure water does not get in and corrode the wiring.

Steve

 

[tmielnichuk]

Thanks,

Just to clarify...

Should I CUT ALL the mentioned wires going into the IRCM (24, 14, 1, 2, 3, 4) and attach them to the new relay? Is there any wires from these that need to be left attached to the IRCM?

"Connect the relay high side to pin 24, "
I read this as remove the wire going into pin 24 on the IRCM and attach to the "relay high side" whatever that is?

"low side to pin 14."
Remove wire from pin 14 on IRCM and attach to the low side of the new relay?

"The other two connections can be reversed, it won't matter. Common to Pin 1 or 2, "
Connect on of the wires from pin 1 OR 2 on the IRCM to the "Common" connection of the new relay?
Or do I use both 1 and 2?

"and the NO (Normally open) contact to pin 3/4."
Do I use either pin 3 or 4 or both of them?

Sorry to ask dumb questions but I'd rather not screw this up.

Thanks again

[email protected]