Ok, I'm stumped here and the main fan won't come on.

- I tested the fan relays by the radiator and the main fan and they both work
- I tested the relay wiring connector
** Orange wire (E) has power >12v
** Tested between the green/white (F) to the tan (D) wire and it's reading around 12v

So I figure the fan should come on....but nothing

I went ahead and wired a bridge between the relay wiring connector and the relay. When I leave the green/white wire disconnected and instead ground the relay (F) to the battery (with everything else connected) the fan comes on.

I'm assuming maybe a weak ground on the green/white wire? Also any suggestions on next steps to troubleshoot this?

 

Im assuming, its a dual fan setup?
Which fan are you trying to run? They don't come on till 2?? and the 2nd at 239.

 

Yes dual fans. Trying to get the primary fan to come on...not so worried about the secondary fan for now.

I've had it warmed up and fan still never comes on. If I can remember correctly when you turn key on before the engine starts the fan will cycle on also (correct me if I'm wrong).

Fan doesn't come on either when key is turned to on or after it warms up to operating temperature.

 

My primaray doesn't come on when the key cycles. (doesn't mean thats right either)
It is controlled by the ECM, IIRC, sooo maybe the ECM isn't seeing what it needs to or the ECM is bad?
I know there is a wiring diagram for these floating around on here someplace.

 

As mentioned above, the car has to hit the temps of 222* and 239*.
The only way to know when you have hit those temps is by using an Infrared laser temp gun aimed at the thermostat housing. Compare that to what you're gage says. It is most likely off , as most are.


I don't know if you can rent them but I bought mine at Harbor Freight on sale for $ 35.00.
They also have a online site.

 

My chip is programmed to kick the primary fan on at 190. I'll have to get scanner on it to confirm when it hits the temp but I dont think that is the issue.

 

Shouldn't the primary fan come on when the ALDL is "jumped" and the key is turned ??

Could try that just to see if the ECM is sending the ON signal properly.

 

You are correct John, it should run the fan when the key is placed to "on" without starting the car.