I bought a 92 Camaro rs, with auto trans and tbi 305, the motor was bad because the previous owner did not notice the big single fan quit working and burned the engine down.
so I found a new 305 and installed it, and put the whole engine compartment back to stock. and the engine runs awesome I could not be happier except for the fan.
the fan works when I turn on the ac, and the fan works when I ground the single wire that goes to the thermal fan switch on the passenger side head, and the fan will come on when I touch the wire to the body of the fan switch when its screwed into the head.
but the fan will not come on when hooked up to a thermal fan switch, I have tried 3 different new switches from NAPA, and just got done installing a new JET switch with no fan.
my stock temp gauge is fairly accurate, and I have a radiator cap with a built in temp gauge, so I can let the car get pretty hot before it overheats and hurts the engine, I turn on the ac to activate the fan to cool it down.

Today while installing the JET switch, before I crimped on the new conector, I turned on the ignition and grounded the single wire for the fan, and the fuel pump cycled then the fan came on, I tried it a couple more times and the same thing happened , fuel pump cycles then the fan comes on.

That's the first time that has ever happened. I am at my wits end, somebody please HELP

 

Not sure about the fuel pump cycling, but how much teflon tape are you putting on? I had this problem once when I put too much tape on it and it would cause the switch not to be able to ground properly to the block.

 

not mutch, just a turn and a half, enough to overlap. I know the switch is grounded to the block because I checked it by touching the single wire for the switch to the body of the switch

 

Read this post. https://www.thirdgen.org/forums/cool...temp+fan+kicks
Your fan, if stock and wiring not all hacked up should/will kick on at temperatures around 220 degrees and quite possibly be higher.

 

thanks, I read the post and it was helpful, but I have a new JET thermal fan switch in the car now and it should kick the fan on at @195 and it does not, my stock gauge is fairly accurate ( belive it or not) and I also have a new radiator cap with a built in temperature gauge.
I have been letting the car start to boil over into the overflow tank witch is @230 and the fan does not kick on, I then go turn on the AC to activate the fan to cool it down.

My next step is to check all the wiring, I would also like to test the thermal switch to verify that it is good ( if anybody has a good Idea on how to test the thermal switch please post your idea, I was thinking about using a test light)
and if that does not work, an aftermarket fan controller is my last resort

 

Sounds like some crossed wires somewhere. The fuel pump should have nothing to do with the fan so. You may have a spot somewhere the fan wire is touching the lead to the fuel pump relay metal to metal so when you ground the fan it shorts the fuel pump on and when it cycles off closes the circuit so the fan comes on. But I am just guessing. Trace the wires back.

 

Since the fan relay and the fuel pump relay are right next to each other, I'd suggest looking REAL close at the wiring in that area.

Make especially sure that any wires that are supposed to be grounds, are in fact grounded. Can't think of any off the top of my head but you know how that is.

You should be able to test the fan switch wiring with the engine running. If there's a cross with the FP wiring, it may act different with it running, compared to key on engine off.

 

ok guys thanks for the replys any and all help is appreciated, today I took the single wire off the thermal fan switch and hooked up my test light for that ground wire, and to my surprise it lit up when I grounded it.
Then I unhooked the fan relay and the test light went out, so I have some crossed wires somewhere or at least some bare wires, this is going to take a while.