JeffP

My dual electric TPI fans stopped working this afternoon, not sure why. Neither one of them works, even with the ac compressor on. I checked all the fuses, are there any heavy duty relays for the fans? Help! I cant drive my car!

thunderstick

Your fan not coming on even with a/c could be caused by (1) your freon being low, needing servicing, or (2) the a/c pressure switch gone bad. Happened to me... The other fan, if you're set up stock, ain't coming on til you're real toasty - about 239*. The a/c pressure switch is the one on the a/c line with a connector on it - can't miss it. Disconnect it and put you a paper clip across the terminals on the connector and then try your a/c system again and see if a fan comes on...

KAM

JeffP

Ok let me clarify some stuff. My fans run used to run when the ignition was kicked on, no matter what the engine temp was. I have the fans like this because I live in Texas and it was very hot this summer. The other fan usually came on with the A/C compressor. All of a sudden these things dont work.....Doesnt make sense.

I replaced the relay, and that didnt do anything. I also checked a 20 amp fuse by the relay, and it was fine too. I even bought 2 new fan motors, but that didnt do it either. I can feel the relay "click" when I turn on the ignition, so its getting the power. The only thing in the way between the relay and the fans is a snap connector, and I dont see how it could go bad.

Seems like I have a pretty large problem on my hands. Please help!

My Slow Iroc-Z

Ummm, here are a few more things to check: I believe there are two fuses under the dash labeled FANS that could have blown. If they check out ok, and your replaced both relays and fans for the primary and secondary fan, get a small piece of wire and jump pins A and B in the ALDL connector under the driver side dash. Pins A and B are the two in the top row all the way to your right when looking at it. With the jumper in place, turn the key to ON but DO NOT start the car for any reason without removing that jumper first. With the key in the ON position and the jumper installed the primary (driver's side) fan will come on. If it does not then eighter your wiring to the fan has a break in it somewhere or the ECM is shot. If the fan comes on then the Coolant Temperature Sensor in the front of the intake manifold may be reporting the wrong engine temperature to the ECM. It has a 2 wire connector and is directly below the TB. Try replacing it with an AC Delco part since it controls other engine functions as well and is relatively cheap (bout $20 for a Delco one) and needs to be accurate. Pull the jumper and let the car heat up. By the way if you are using the guage in the dash to get the engine temp, it may be totally wrong. If you want you can replace its sender which is located in the driver's side head by the #1 cylinder. As a note use a Delco part here also, I put a Wells sender in there and it would read the temp to be 250 degrees when the car was right around 200 degrees. If the fan still doesn't come on then get under the car and pull apart the connector on the secondary fan switch in the passenger side head between the last 2 cylinders. Turn the key on and ground its wire. Now on my '89 Iroc if that wire is grounded both fans turn on. I believe the ECM thinks that since the only time that fan will come on is when the car is at around 250 degrees, too hot, and it will turn on the primary along with it to cool faster. Eighter that or it grounds both fan relays for the same reason. I am not sure if it is the same way on other years as well. If the passenger side fan comes on along with the driver's side and you replaced the Coolant Temp Sensor I believe there is something wrong with the ECM or the wiring from it to the relays. In that case to save some money and a **** load of time just replace that fan switch with a cooler temp one, like from an '87 Buick Regal T-Type engine VIN 7 or a Hypertech one available in Summit. The Buick one will turn the fans on at ~200 off at ~190, Summit states the temp the Hypertech switches work at in the Catalog. Or you can inspect/replace the all the wiring from the ECM to the primary fan relay and from that relay to the primary fan. If that don't work then replace the ECM. If only the passenger side fan comes on then you eighter have a problem with the wiring from the ECM to the primary fan relay or the wiring to the fan itself. If no fans come on at all then you definately have a wiring problem and need the check all wiring to both fans, relays, and fan switch in the whole cooling system.

Hope it helps and isn't too confusing!
Good Luck!

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1989 Iroc-Z L98 Original engine-58K miles!!

SLP 1 3/4 SS headers, Hooker Areochamber catback, no cat, BBK AFPR, Hypertech 160* fan switch, ported and gasket matched plenum, TB coolant bypass, relocated MAT sensor, screenless MAF sensor, K&N filters, Accel cap and rotor, Taylor SpiroPro 8mm wires, Bosch Platinum plugs, Mobil 1 Synthetic 15W50 motor oil, and more to come...
Best ET- 14.24@96.76MPH / 2.17 60ft on street tires with the crappy B/W 2.77 gears.

Homepage currently under construction: http://www.iit.edu/~wicktho/len

JeffP

The 2 fuses under the dash are ok.

Putting a paper clip in the A & B pins does not turn on the fans either.

The wire that goes into the fan switch on the passenger side cylinder head was removed from the switch and grounded. When the switch reaches a certain temp, it grounds out, so I simply bypassed the fan switch all together. I did this several months ago, and it never gave me any problems, nor should it have caused the cooling fan failure.
Grounding the wire is doing EXACTLY the same thing.

I guess my wiring has shorted out from water, is broken, or my ECM is shot.

Thanks for all the help guys, I guess Im SOL.

My Slow Iroc-Z

Sorry I couldn't help!

My Slow Iroc-Z

This is what you do....Put the Buick fan switch in the head. Use your new fan relays and run the wire from the switch directly to the turn on wire on the relay. Go directly to the battery with a 10 guage wire with an inline fuse to power the relay. Ground it to the chassis in a convient spot where its mounted. Now hook the relay directly up to the fan. Use the second relay and connect their signal wires together alone with the wire fron your switch, and hook it up to the other fan. Now when the switch in the head closes the fans turn on and you still have full control. This way it bypasses the ECM and the stock wiring!
Good Luck, and let me know how it turns out!