I'm relatively new to this forum, but I've been reading it since picking up my car- an 87 350 TPI IROC.

I've had problems with the charging system in the car for awhile, I'm on my third starter, second alternator, enough batteries to power a city. A couple months ago I replaced the alternator on the side of the road (in the rain, awesome) and forgot to reattach the power for the fan relay thing when I reconnected the battery. Clearly, after letting the car idle so it could recharge, it overheated and sprayed coolant everywhere.

After cleaning up that mess, and reconnecting the fan properly (aftermarket Flex-A-Lite dual electric), the fan doesn't work. It tries to, because when the car hits 150 degrees or so, my voltage nosedives.

Also, now the car won't start. I've read on here that the exciter signal for the alternator comes through that fan relay. I'm not a mechanic, just a hobbyist, but I'm fairly proficient with test equipment, just not sure where to look first.

I'm open to any suggestions. I feel like I keep fixing the same things over and over without ever getting to the cause. So frustrating!

 

If it were me, I'd try replacing that relay. If you had dual fans from factory, then there should have been a relay for each fan - is that still the case? Replace both. If only one relay, then I'd say that is your problem, one relay trying to run two fans - fans draw a ton of current upon initial startup, up to 20 amps each - if you have one 30 amp relay, its getting toasted.

I'd also look into a seperate fan controller and ditch the old factory wiring - especially if your aftermarket fans draw more than 11amps each (factory draw was 11amps each fan) - that old factory wiring may not be able to power those new fans.

It won't affect the computer at all to have the fans wired on seperate controller(s) - the computer tells the primary fan when to start/stop, but it could care less when/if that happens.

 

Check the FP/fan fuse in the underdash fuse panel. Then go from there and check for power with key on at the fan relay(s) and the tan/white wire at pin F of the alternator plug.

 

like the other said it could be a bad regulator or blown fuse or else something else in your car could be shorting something else i had that happen in my car and it destroyed my battery if you dont have a voltimeter get one and test all the fuses and wires and even look for lose wires under the hood or around the car

 

I installed an aftermarket fan controller with the fan, and had my share of trouble with it. Turns out that each fan draws 14 amps, and the controller had a 24 amp fuse. I replaced it with a 30, and put in a circuit breaker that resets, so if it trips the fans will shut off for a minute, then come back on.

The FP/ fan fuse hasn't blown...

I'm thinking maybe I should simplify it and just get the good flex-a-lite adjustable controller. Could that be what's giving me fits with the charging system too?

 

With the flexalite controller, you will still need to be sure that your alternator is getting power on the tan/white wire with key on. That is a good fan controller, Ive installed it a few times. I recommend using a relay to run each fan and using the controller to activate the relays. This lessens the strain on each part.

 

Well, just got back in town and had a chance to look at the car. The battery is completely dead. All of the fan wiring is melted and unraveled, etc. It looks like a bomb went off under there. So brown wire is out (melted in half). Could this have happened from just getting hot, or is something haywire going on? Where do I start now?