Coolant fan wiring

Mattc3366

Mattc3366

Active Member
tonight I was playing with HP tuners and attempted to activate the cooling fan and I got nothing. No relay click or anything. Attached is a photo of the relay I have it hooked up to. If I power the bottom left pin the fan turns on. The two on the right side have 12V. That leaves me with the top left pin. I would have thought turning the fan on in HPT would give me a signal here but I don’t get anything but I’m also far from an HPT guru. I have not let the car get hot since doing this so I was doing it as precautionary testing before being road ready. Next step is to just let the car warm up and see what happens.
37003
 
Ross

Ross

Goblin Guru
What donor car?
You can follow my signature, to set up your signature.

For my LSJ, the goblin will only turn on the high speed fan.
The low speed fan requires the 2nd fan, which isn't installed in a goblin.

AllDataDIY Login
37004


After looking at this wiring diagram, I think my LSJ is using cool fan 2, which is a different relay than you pictured. Nope! I was wrong.
On my LSJ fusebox I have it labeled as AC FAN.
 
Last edited:
Ross

Ross

Goblin Guru
You are right, a goblin uses fan 1. Fan 1 won't turn on unless it gets ground.
In a Cobalt, the Cool SER/PAR relay will give it ground if it energized. If it isn't energized, then power goes thru Fan 2 (Each fan getting 6 volts).
In a Goblin, there is no Fan 2. I'm not sure how the harness is modified. Fan 1 could just go to ground. Or maybe it requires the Cool serial/parallel relay to be working.

A while ago, I looked at adding a resistor in fan 2's place. Then the goblin fan would work at low and high speed, like the Cobalt.
 
Last edited:
Ross

Ross

Goblin Guru
If your relay isn't clicking... then it isn't a ground issue with the fan 1.
The PCM is suppose to provide ground to the coil on the fan 1 relay.

PCM connector C1 pin 51 is a dark green wire that switches to ground.
37009

That dark green wire goes thru the engine-to-body connector C161 on pin C
37008


Then the wire enters the fuse box on connector C1 pin E10.
37017


If you did your own wiring harness, most of the dark green wires get connected together for the GM Low Speed LAN... hopefully this dark green wire didn't get added to that.
Do you know how to use an electrical meter to check for continuity on this dark green wire?
 
Last edited:
You must log in or register to reply here.
Top