97 lt1 trans am fans not working

**96formula8az28** · 03-02-2015, 08:48 PM

OK guys its been a while. But I'm back with a new car I just bought. 97 trans am polo green 6 SPD. Its a project. Long story short when I bought the car the fans were rigged to hell and back on a switch to the battery. I don't like that shit so I pulled all that out to put to stock. I have power and grounds to relays if I jump relay they come on.I replaced the iat and coolant temp switch in water pump. And ecm still will not kick fans on. All fuse and relays are good.. Any leads?
Thnx all.

**96formula8az28** · 03-02-2015, 09:02 PM

Also. I think I may have a bad ecm. If I unplug a sensors does not change way it runs.

**englundjd** · 03-02-2015, 09:07 PM

is the pcm commanding them on? to know that you'll have to do some datalogging.

**englundjd** · 03-02-2015, 09:17 PM

is the pcm commanding them on? to know that you'll have to do some datalogging.

**95albinobird** · 03-02-2015, 10:00 PM

datalog. you could just have a bad wire in the harness this is when section 8 A of the shop manual is helpful.
look here
http://www.mediafire.com/?40mfgeoe4ctti

**96formula8az28** · 03-03-2015, 03:09 AM

I don't think the ecm is telling them to come on.

**96formula8az28** · 03-03-2015, 03:15 AM

I can say if I take a test light to the blue or green wire on passenger fender (you know the 2 harness connectors) and poke them with my test light on the positive side of battery the fan goes on. Could this be a faulty ecm?

**Revolutions** · 03-03-2015, 03:50 AM

If you haven't already you should connect a scanner and see what the computer is showing for coolant temp or at least do a continuity test of the CTS.
Do you have A/C on the car if you do turning it on should turn on the fans.
1997 uses pins 5 and 6 on the 16 pin DLC to initiate what is called "field service enable mode". That should cause the fans to come on.
After placing the jumper on the correct pins, turn the key to ON (don't start). If the fans work after jumpering the DLC, your PCM is
capable of operating the fans and all fan wiring/relays should be ok.
If they don't come on in field service mode you can troubleshoot further with the attached schematic.
fan_schematic_1995.jpg

**Spartan7** · 03-03-2015, 05:17 AM

The PCM should be the last thing you suspect, they don't often fail (especially with two related circuit drivers). The first thing I would suspect is your wiring from the PCM to the relays. Have you checked for continuity there?

derp.png

**96formula8az28** · 03-03-2015, 08:39 AM

Yes I got good power to the relay. I haven't yet put a scanner in the car. Due to the fact of my scan tool got stolen at my last job. So I use a jumper wire to pun 5 and 6 on the DLC? Or I put power source to 5 and 6? I just got the car 4 days ago and it been rigged with aftermarket switch to turn the fans on. I rather my PCM to do its job with out rigging. I'm going to go with further testing today