Hello,

I did a 91 tbi to 87 tpi 305 harness conversion and my single fan only turns on when I have it on an AC setting? Any Ideas?

Thanks,
Champion

 

I emailed the harness conversion co that did it and they said that the swap doesn't touch the fan so i am guessing i might have a bad fan switch or something? Part number for a TBI fan switch, color of wires? etc would help

 

On my TBI, the fan system was a stand alone. Where TPI is controlled via the ECM/CTS.

I think the fan on setting is way up around 210/220 stock, but dont quote me on that.

 

Yeah i was told the temp is set high however my temp gauge in the car was reading max out at 260 not sure why.

 

Your cooling fan should still work the same as it did, the tpi card used the standalone system for the primary fan and the ECM controlled the secondary. Your tbi car uses the standalone system for the single fan, check and make sure the wire is connected to the fan switch on the back of the passenger side head. they are prone to getting brittle and falling off. also you can simply ground that wire and it should turn the fan on.

 

Is there a way to test that wire to the fan switch?

 

yes, simply ground that wire and the fan should turn on,

 

if it doesn't then the wire probably is gabage right?

 

If your fan is coming on when you turn on the ac your fan and relay are good, the only thing left is either a bad fan switch or the connection to the fan switch is broken. I have long since gone away from relying on the fan switch to turn on my fans; I get an adjustable fan switch from the auto parts store (the cheap one that has no relays, about twenty bucks). The switch only has two terminals, locate the wire that originally goes to the oem fan switch and connect it to one terminal of the adjustable fan switch, then connect the other side of the adjustable fan switch to any chassis ground, then mount the temperature probe to the radiator. Now start the car and adjust the pot on the adjustible fan switch to the temperature you want the fan to come on at.

 

Thanks i will test it tonight and post my results!

 

I tested it and the fans kicks on when i ground it! So i am guess i have the wrong fan switch! I am going to put an 91 tbi fan switch in tomorrow! Should work right?