Thread: Temperature Problems

Thanks for that. I'll try to check all the wiring tomorrow when I check hoses, temps, and all this other crap.

Ok. I was looking at stuff today and here is what I have.

The lower coolant hose is only slightly cooler than the upper. So the rad probably isn't clogged.

I let the car warm up to see if the fans would come on. It hit 225 by the scanner, and 235 by the gauge, and neither fan kicked on. What I think is weird is that that scanner read higher than the gauge with the old temp sensor, and lower than the gauge with the new temp sensor. So something is screwy there, too.

I confirmed again that both fans DO come on when the air conditioner is turned on. Regardless of engine temp they turn off about 1 minute after I shut off the air conditioner.

The fan fuse is good, and two out of the three relays are good. I took the third relay to auto zone and talked to a man who seemed to know a lot about GM cars and he said it is highly unlikely that the third relay is the problem.

I looked at the wires that I could see, but they have the black plastic covering most of them so they should be good under there. The exposed wiring and connectors all look fine.

Any other possible solutions?

Here is one thing that I just though of. Probably not the problem, but worth mentioning.

I have a set of aftermarket fog lights that use their own custom wiring harness. They have both the fog lights themselves, and halos. I have them wired directly into the positive on the battery, and then grounded out to the coil pack bracket. Anyway, the fog lights themselves (not the halos) stopped working at probably about the same time that the fans stopped working correctly.

Could these two be correlated? Maybe I'll undo all the wiring for the lights and see if that changes anything...

The horn has a ground.

Is that on the drivers side? Or both? The ground wire on the harness was really short so I was limited as to where I could put it. I needed them finished by that night, and was really in a hurry. If I have that, maybe I'll extend it.

but yes.

Are you running an aftermarket PCM? IIRC the fans are supposed to kick on at 220*, if you are exceeding that by the PCM, then it makes me wonder if the command on temp isn't messed up. You can't really go by the temp gauge on the dash, they don't really provide accurate information.

Originally Posted by Reptile

Are you running an aftermarket PCM? IIRC the fans are supposed to kick on at 220*, if you are exceeding that by the PCM, then it makes me wonder if the command on temp isn't messed up. You can't really go by the temp gauge on the dash, they don't really provide accurate information.

I said earlier that I checked by the gauge and with a scanner, and the fans never came on. And the PCM is stock as far as I know. And I highly doubt that the moron I bought the car from ever touched it. I would check them myself, but I don't know anyone with a tuner, and I sure as hell can't afford one. Besides, the car is only worth about a thousand bucks.

Oops. I missed where you said Driver side brace. I'll unhook them in the morning and see what that does. It would be pretty awesome if I was able to fix both problems with just a couple bucks worth of electrical wire.

And sorry for not thinking of that earlier. I've been really stressed lately.

OK, I just went through the diagnostic tree on Dealerworld....when I get to the A/C system fan turn on, it tells this.

Check for the following conditions:

• Poor connection at the PCM, cooling fan relays, or cooling fan motors. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.

• Damaged harness. Inspect the wiring harness for damage.

like you said on im it has to be somthing related to what you just posted

I had the PCM exposed when I pulled the coolant recovery bottle and everything looked fine there.

Two out of the three relays are good. The third, I don't want to spend 12 bucks when I really have no idea if that is the issue.

The connectors all look fine. I checked them again today.

Harness. Is that referring to the main wiring harness for the whole engine bay? I've looked at most of it that isn't covered by the black plastic protector stuff. I really didn't want to start pulling that off, but I can if need be.

OK, I found the wires you need to look at, and trace from the PCM to the fans.
It's going to be pins # 5 & 6 on the BLUE pcm connector. 5 is a dark blue, 6 is a dark green wire respectively. If you pull the PCM connector out, and look into the end of it, they start on the lower left hand side, and go from left to right in numbers. Those two control the temperature low speed fan controls. If those wires are pinched and the circuit is open somewhere, then they will not operate on their own, but will when you turn the AC on.

Originally Posted by Reptile

OK, I found the wires you need to look at, and trace from the PCM to the fans.
It's going to be pins # 5 & 6 on the BLUE pcm connector. 5 is a dark blue, 6 is a dark green wire respectively. If you pull the PCM connector out, and look into the end of it, they start on the lower left hand side, and go from left to right in numbers. Those two control the temperature low speed fan controls. If those wires are pinched and the circuit is open somewhere, then they will not operate on their own, but will when you turn the AC on.

Good man!

When I was trying to get the coolant bottle off I was trying to undo the connectors on the PCM so that I could get the airbox out of the way (Yes, I now know this wasn't necessary) I undid the bolts the hold the connectors on, but still couldn't get the connectors off. Am I just a moron, or is there more to it?

The connectors are held on tight by a 7mm bolt each, you have to unscrew these and pull them out. BE SURE to not over tighten the bolts when you put them back in. They are just there to keep the PCM from being disconnected, not to hold it down. Check and make sure all of the pins are pushed all the way down, and there is no corrosion. There should also be a silicone seal around each connector where it connects.

I had the bolts unscrewed, but the connectors wouldn't come off. I even tried prying them off with a screw driver and a couple other things. Are they probably just corroded?

they might be stuck on pretty good, sometimes the seals tend to stick. Make sure to kind of feel the bolts "click" when they finally back all the way out of the bracket.

Ok, I'll tear the box down again probably tomorrow, and then I'll let you know.

Thanks guys for all your help.