Hi,
I tried posting this in another thread, but think it might be better to start a new one.

92 350TPI.

I have the dual fan setup, and I noticed that the fan on the passenger side is always on. Is this the primary or secondary fan?

I thought that maybe this was the fan that is controlled by the coolant temp sensor? So while looking fro this sensor, I noticed that a wire has been cut (see image).

Looking at my wiring diagram, there is a yellow wire from the ECM to the coolant temp sensor. I need to get some jack stands to see if this wire goes to the sensor or not. but if this is the wire. With it being cut, would that cause the passenger side fan to always be on?

 

Passenger side fan is secondary. Yellow sensor wire is unrelated to the secondary fan.

There is a single black wire on the secondary fan switch that's located in the passenger side head. It's not the one in the pic. But if the black wire is cut and by some miracle is touching a good ground, your fan will run.

But the more likely problem is a stuck relay or switch. When the engine is cold, unplug the wire from the switch in the head. If the fan stops running, you need a new switch. If it's still running, the relay is stuck and needs to replaced. Unplug the relay to test. Not exactly sure where the secondary fan relay is located, but I checked the wiring diagram and if your find a relay with these wire colours, you've found it:

Orange
Black with pink stripe
Brown
Grey

 

I just took a second look at the diagram, and there's also an A/C pressure switch that, if defective, could cause the passenger side fan to run constantly. And it's easier to check than the other 2 items I mentioned above, so you might as well check it first.

The switch is located on the high pressure A/C line inbetween the condenser and the evaporator, near the passenger side strut tower. Turn the ignition on. Unplug that switch, and if your fans stop, you've found the culprit.

 

Hmm interesting, the AC doesn't work right now. So I wonder if this could be it.

Do you happen to have any pics of what any of these switches look like?
I'm looking at O'Reilly's website. They show a low and high side pressure switch.

HOpefully this is it.
Still need to lift the car and see what that cut yellow wire is.

 

http://www.oreillyauto.com/site/c/de...&keyword=36669

 

That would also cause the primary to run as well, though.

 

hmm, the primary does not turn on with the key. So might not be this.

The primary does turn on when I put a jumper on the ODB1 port to get the codes. Which I read is normal.

So now back to trying to find the switch for the secondary fan. Where is it? I'm not sure what it looks like.

 

Passenger side head, almost directly above the starter. There is a knock sensor which looks similar in the block just behind the starter. Switch looks like this one I linked from NAPA...

http://www.napaonline.com/Catalog/Ca...RecType%3aA%29

If you find that the wire is cut/broken, you may also get the connector from NAPA or other parts store.

 

I think I found it, but looks a little different at least from where I can see it from under the car.

If I unhook the wire that is attached to it, the fan stops. Hook the wire back up, the fan comes on. So it's most likely a bad switch right?

 

That's it. Buy a new fan switch.

 

Fixed!!

and the car even gets up to temperature now too.

Thank you everyone.