Hi all! What a great forum. I have an 89 GTA in Fire Red, 5.7 L98 automatic and factory T-tops that I acquired as a project.

The wiring for the cooling fans has been butchered so they never come on and it overheats. I'm looking for some help in figuring out how to diagnose this issue.

The temp gauge in the car works fine. I am assuming there is only one coolant temp sender, and that is to the gauge?
There is a cheap aftermarket relay screwed to the radiator support that is connected to the harness near the battery.
There is a splice in that wiring harness near the battery positive terminal. On a hunch, I jumpered to it from the positive battery terminal, and the right hand fan runs.

On the lift, there is an electrical plug, connected to a fitting on the bottom of the left hand fan housing. There is an identical plug dangling there not connected to anything. I'm really confused by the whole thing.

Questions:
Where is the trigger signal for the fans to come on generated? Is it the ECM once the temp output of the coolant temp sender hits a certain voltage?
I am pretty certain there would be a factory relay triggered to pass on the higher current to the fan motors. Where is it?
What is the best way to determine what is failed in this system?

Thanks for any help!!!

 

Hi folks. well I've basically ripped out all the jury rigged bullshit including an aftermarket relay with a temp sensor that was taped in between fins in the radiator, restored wiring where it had been spliced to send power to the substitute relay setup (soldered and heat shrink insulation), and I've checked all the relays I can get my hands on. The coolant temp sender in the passenger side cylinder head has a white wire and a mechanical splice to a black wire that runs into the harness sheathing near the starter and goes who-knows-where. Looking at the wiring diagram with the assistance of some Hair Nation and a tall icy glass of Jim Beam and Coke, I believe that should actually be a green/black wire to a relay so that when it hits 220F it should close to ground and ground that terminal to close the relay and send 12V down the Black/Pink wire to the right hand fan.

Looking underneath the car, the left hand fan has a black/pink wire that was previously connected to the jury rigged relay setup. I can jumper that to 12v and the fan spins. Still need to check the right hand fan to see if it works. The right hand fan connector has a blue wire and a black wire, the black wire goes to ground and the blue wire has a cheap mechanic splice to another wire in the sheathed harness that runs along the bottom of the radiator.

Bonus: each fan has a second two wire connector just hanging there not plugged into anything, IIRC one wire is black and the other black with a pink stripe....which should be hot when the appropriate relay closes according to the handy diagram. Try to trace continuity and figure out where each of these wires terminate is tough by yourself......

One last thing that I think will help me: I have relays in the following locations: TWO on the driver's side firewall between the brake cylinder and the fender. One has been replaced with a newer PN however the diagram on it is the same as the original PN. There is also another one of these relays on the PASSENGER side attached to a bracket on the passenger side of the radiator near the air box, and lastly there is a fourth one secured to the fender liner on the passenger side near the air box. What is the function of these specific relays? They all have constant 12v on an orange wire that seems to correspond to an orange wire off the positive battery cable and another terminal opposite that is hot when the key is turned on. All of these relays close when the appropriate terminal is grounded and show continuity on the terminals between ground and the accessory output so far.

The secondary fan circuit is much simpler and I'm considered just installing a jumper from the passenger side coolant temp switch to the appropriate terminal on the correct relay, then either correcting or installing a new wire from the 12v output of that relay to the RH cooling fan to at least get one of the automatic fans working. It appears that plug and wire has been replaced with aftermarket (white wire) and the splice to a 20ga black wire seems like another "short cut" that is probably not correct anyway.

Thanks for any help peeps!!!

 

Pink w black stripe is supposed to be switched ignition. Sounds like maybe that wire got sodomized somewhere upstream of the actual relay wiring.

Black w red stripe and black should be one of the fans, from the factory, if they're both BIG FAT wires, like #12 or so.

As far as the relays, not all of them are related to fans, at least in the factory setup. The ones that are, will have 2 small wires going to their coil terminals, and 2 BIG FAT wires on the contacts. Some of the other relays (fuel pump for example) don't look like that. We out here can't somehow look at your car and tell what Stimpy might have done to it in the meantime; after all, they keep inventing smarter idiots all the time, and the crap the idiots do just keeps getting harder to figure out as they get more resourceful. Since YOU'RE looking at it, YOU'LL have to find all the pecker tracks on your own, unfortunately.

Photos of all this stuff might help us help you identify what's not part of the fan wiring at all, what's factory, and what's diarrhea that Skillet left behind.

 

I'll have to see if I can post some pics of what I have vs what the factory wiring diagram shows. Which of the relays I described are the actual fan relays? The diagram doesn't help much with that..........

 

Ummmm...

Once Skillet has got in there with his dykes, none of us out here can guess what ANY of it is, especially with as vague a description as you gave. Who knows what evil lurks in the hearts of idiots. You're the only person close enough to see your car, regardless; butt it's too dark out now for me to see it anyway.

Indeed... "the diagram" doesn't know too much about what Stimpy did to your car. It only tells you how IT CAME, not HOW IT IS NOW. 2 very different things obviously.

 

The best advice I can offer, other than what Mr. Sofa has already provided, is to get yourself a copy of the Helms Factory Shop Manual; they come up frequently for sale on ebay. In fact, there are several listed right now, and fairly inexpensive.

Stay away from Haines, Chilton, etc.; they are incomplete, sometimes incorrect, and cannot possibly provide electrical system help, which, I suspect, is something you're going to need even beyond the cooling fan issue. It seems that when knuckleheads get a pair of diagonals anywhere near wiring, they know no bounds, IYKWIM.

Good luck.

 

So, I got under the car, and looked closely at the wiring to the fans. The rats nest of wiring that I had cut out and yanked out at the battery and connected to the aftermarket relay setup, also was connected to an extra set of wiring to the fans which was wrapped around and taped to the factory harness. The factor harness plugs were just tied off. So I pulled all that **** out, and plugged in factory harness plugs into the fans. I had previously cut away the factory ground and hot wiring from the added BS and repaired it and reconnected it to the factory harness there at the positive cable junction near the battery.

And whaddayaknow. While the primary fan does not work (and does not come on with the AC like it should), the second fan DOES come on when the coolant temp hits 220, just like it's supposed to, and runs until the coolant temp drops below about 210. The air conditioning piping is damaged so that needs repair as well, and there is a poorly wired security system hanging by it's harness on the driver's side floor so there might be an issue there - but at least my cooling issues are resolved enough that I can drive the car!

I finished an oil and filter change, and a tune up with spark plugs and an Accel cap and rotor. Half of the spark plugs weren't even tight, there is old fuel goo on the outside of them lol. It ran OK before, it's noticeably better now. And now that the entire cooling fan wiring setup has been restored to factory and at least one fan works, it can be driven while I work on other stuff..........like getting rid of that security system thing hanging from under the frigging dash......or rebuilding my sloppy steering box.

 

Awesome! Too bad more of these situations aren't like that, where the factory stuff is undamaged. In way too many like this, Stimpy gets in there with his dykes and "cleans up the engine bay", and in so doing, sends the car to the scrapyard.

Troubleshooting just the primary fan is a MUCH more manageable task. Hopefully the problem with that, isn't butchery.

Another one of those "improvements" that always seems to go sideways eventually. Those POSs plant a dagger right in the heart of the car, just waiting for its chance to kill something. Besides being overall altogether WORTHLESS; they're just too easy to get around by stealing the car some other way besides starting it up and driving it.