Here is what happened. I start the car and everything is fine, go out next day and the fans and alternator are not working.

I have been checking older posts for two days and still cannot find what I am looking for.

The car is a 1987 Pontiac Trans Am with the 5.0L FI engine with an automatic. I noticed the alternator was not charging and the passenger side fan, which had been hardwired through the relay, were not coming on. I located the relay and took it apart and that is when I found a piece of wire connected inside the relay that made it turn the cooling fan on when the ignition was on, I have purchased and installed a new relay. The car has the voltage gauge, not the light.

I do some reading and discover that the tan wire with white stripe are connected to the fan relay and alternator. I go out and probe the wires with a multi-meter and find the wire. I check for voltage and there is none. I then jump the battery lug from the alternator to the tan/white wire and the fan starts. I go ahead and start the car and low and behold I am getting 14.5 volts at the battery. The alternator wires on my car are a brown, tan/white, a thinner red, and a thick red. I am using an Ohio Generator high output alternator so the two red wires are connnected to the battery lug, the tan/white is on the "2" terminal on the regulator and the brown wire is just capped and tied up. I, and the previous owner, have not had a problem with this.

I then did some more reading and found out there is a "fan" fuse under the dash. I go ahead and try and check that, but the writing on the fuse holder is gone. I did find one burnt up spot where a fuse used to go, but no fuse there and not label so I do not know what it goes to.

I need a picture of the fuse panel with the spaces for the fuses. Also does anyone know where the tan/white wire go from the alternator to the fan relay. Is it into the dash, to the ECM? I just need to find where the break in the circuit is so I can fix it. I think since I am getting the fan relay to work the break has to be before the alternator and not after it. I did get a replacement relay so now the fans will come on when they are supposted to. I also know that I could just use a jumper wire from the alternator lug to the tan/white wire, but I would rather just fix it right. Also the car has the voltage gauge, not the light.

I know the post is long and maybe hard to follow as I left out some non important stuff during testing.

Thanks,
Eric

 

I worked on it some more today and traced the wire back to a burnt up spot in the fuse panel. I removed the fuse panel and discovered the previous owner had put a splice in fuse holder that is powering the wire. The incoming wire is a larger orange wire, looks like the one that came from the fuse box, and just added a new fuse holder. I redid the fuse holder since the fuse box place was burnt up and when I checked it with the multi meter it was only getting 6 volts. I ended up just running a new wire and new fuse holder to a switched 12 volt source in the fuse box. I could not locate any type of main power relays that feed the fuse box. If anyone has that information that would be very helpful.

Thanks,
Eric

 

You ever figure that out? Got the same problem only after a motor swap. Same car as you, just carbbed not FI.

 

same problem as Dragesmcdoodle either of you guys figure this problem out ??

 

Not yet, checked my fuses and the computer fuse was dead so I replaced that one. I had the fan wires ran direct with my choke wire to the fuse block so I'm gonna hook them back up original and see if the ecm fuse does any different, not that I think it will.

 

alright im gonna keep at it an if i get it figured out it'll be sure to post back

 

Well that did nothing as expected. Tested the alt with the car running, alt put out 11.7 volts. Enough to keep her running but not enough to charge. Fan still didn't kick in though. I don't mind the fan running all the time. I ordered a 140 amp bullet alt from tuff stuff. See how that goes.