Thread: Temperature Problems

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.

Originally Posted by TDCRacing

fan 1 wich is on the drivers side will come on at 212*F fan 2 wich is the only other fan lol (pass side) will come on at 226*F

.....

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.

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?

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!

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.

I wasn't able to trace the wires the full way because I couldn't get the damn rad out of the way, but from what I can see they are fine.

Also, I undid all the fog light wiring and can confirm that did not fix the problem.

Is there any way to temporarily bypass that relay? The one that is different than the other two, and I didn't want to buy it?

I'll look for you tomorrow and see if i can find a way to do so.

@TDC: Did you find anything?

Having a problem with my 98 GT as well. Can't get the fans to come on EVEN with the AC on. Coolant temps according to the gauge is around 190 or so.

Just finished with a LIM and UIM gasket and upper plenum replacement and also put in a new coolant temp sensor as well plus a new t-stat while everything was apart. Funny thing is if I disconnect the wiring harness for the temp sensor the fans come on.

While they were running I would disconnect each of the three relays and a fan would go off when doing so. Wondering if it has something to do with the harness? Temp isn't getting high enough for the fans to come on with the AC off but puzzled why they don't go on when the AC is running?

Originally Posted by TDCRacing

I'll look for you tomorrow and see if i can find a way to do so.

Bump. Did you ever find anything?

Originally Posted by spenc938

@TDC: Did you find anything?

Sorry forgot all about it. I'm off tomorrow and will look when i get up.

Originally Posted by TDCRacing

Sorry forgot all about it. I'm off tomorrow and will look when i get up.

Thanks man. I want to buy a few things for the car, but can't spend the money until I figure out what the fans are going to cost me to fix.

Originally Posted by markh

Having a problem with my 98 GT as well. Can't get the fans to come on EVEN with the AC on. Coolant temps according to the gauge is around 190 or so.

Just finished with a LIM and UIM gasket and upper plenum replacement and also put in a new coolant temp sensor as well plus a new t-stat while everything was apart. Funny thing is if I disconnect the wiring harness for the temp sensor the fans come on.

While they were running I would disconnect each of the three relays and a fan would go off when doing so. Wondering if it has something to do with the harness? Temp isn't getting high enough for the fans to come on with the AC off but puzzled why they don't go on when the AC is running?

fan 1 wich is on the drivers side will come on at 212*F fan 2 wich is the only other fan lol (pass side) will come on at 226*F You're fans are not comming on because they are not suppose to come on yet if you're temp is only at 190*

When you disconnect the temp sensor it is telling the pcm that the sensor has gone bad (it defaults to a set temp) and it automaticly cuts the fans on.