2manytoys

iTrader: (9)

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First off lets start with the basic problem. My low speed fan (fan 1) is not running. My high speed fan (fan 2) is working properly.
1) I have checked the relays and they check out according to the Haynes trouble shooting. When the fans are commanded on the relays click like they are getting the proper signal to turn on the fans. 2) The fan motor itself is working with direct 12v and ground jumpers. 3) I have HPT and can command the fans on/off. When I command fan 1, nothing happens. When I command fan 2, the fan on the passenger side comes on. During normal operation I logged to see when the PCM commanded the fans and when it commands fan 1 it does not come on. Fan 2 is working properly.

So what am I missing here. Under all these circumstances I never get a ground to the fan 1 connector. 12V+ is there but no ground. I tried to go through the relays and check for grounding of the circuit but get lost with the whole 3 relay setup. Anyone have some advise as to what to check from here?

Also the one fan only comes on when the coolant temp reaches the high fan setting.

LS6427

iTrader: (2)

1998 F-Body fans are supposed to come "on" and go "off" together.

They are also supposed to operate on "low ' and "high" settings together.

I think you fan motor for #1 is failed.

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eseibel67

iTrader: (10)

Motor #1 runs with direct 12v. PCM is commanding the fan, but nothing.

Is this more likely a relay problem?

OP, I know you said you checked the relay, but is there another relay in the block with the same values you can sub as a tester?

LS6427

iTrader: (2)

Oops, missed that. So yeah, relay or a bad wire.


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2manytoys

iTrader: (9)

The relays are fine. I can swtch them with one another and I get the same results. What I am relly looking for is how to troubleshoot the wires. Obviously something is not getting the proper signal but is it a ground or a 12v+? Anyone have a diagram of what wires are energized when?

2manytoys

iTrader: (9)

OK. I finally got the fans working properly. Apparently a relay can check good but still not work properly. I found a diagram over on PT.net on the wiring of a three relay fan system. The relays would click and send the signal through the correct pins on the table but would not transfer the volatge when plugged in the car. I ended up replacing the low fan relay and the #3 relay as niether one was doing what it was supposed to be doing. All is working good now.