Thread: Temperature Problems

I'm not good with relays...but im sure we can figure out something with a cupple relays and a switched ingition source maybe if we can't figure out anything else.

Originally Posted by Sabrewings

Here's your wiring diagram for the cooling fans.

On that diagram...look at the bottom left and right....where are the low and high speed fan controls located? The low is obviously not working. Is it a relay of some sort??

Those are the wires going into the pcm.

Looking at it again that has to be what it is...the low speed control module. I'll trace the wires comming off of that relay and see where it goes.

Isn't the low speed control module the pcm itself?

And the high speed doesn't work either...

Your right...the high speed wouldnt control the fans when the ac is turned on.

And this means...? That we're at the same place we started at?

Well, I just unplugged the CTS. This keeps the fans on all the time which basically solves the problem, even though I do lose the temp gauge. It wasn't even close to being accurate anyway.

I would still like to fix this correctly if anyone can think of anything. The Check engine light caused by the unplugged CTS is bugging the hell out of me.

I just replaced manifolds (2) and everything was fine except for coolant sensor code. Replaced coolant sensor, purged system of air pockets. Now gauge reads hot, but also varies. Never had the problem before! I'm perplexed.

!0 years as a mechanic 1984-94 ...Feb 2000 se with gt 3.8
Parts that have been replaced:
Coolant sensor
upper (delphi updated) and lower manifolds, felpro gasket sets
2 thermostats
lower rad clamp
Map sensor
pcv valve from kit
radiator cap 16psi
Dexcool replaced and comprehensive flush prior (system seems brown sludge free)
No visible leaks.

I replace the the thermostat since the last post, I noticed that the thermostat that came in the upper intake kit was not allowing the motor to heat up at times. now it is overheating. Seems there is an air pocket in the system as well.
The way I purged the coolant system is as follows:
At a cold state, I remove the rad cap and top off coolant. brake open the bleeder on the thermostat housing... then close bleeder.
Start the motor, turn heater on high. wait until coolant begins to cycle (thermostat opens) crack the the bleeder again for sign of coolant ...then close.
Rev and hold motor at 2200 rpms and top off radiator with coolant.
Replace cap at this time, with rpms at 2200.
at idle I crack the bleeder once again with only coolant coming out.
heater on high is pumping out plenty of heat.
Drive the car 350 miles in 2 days.. gauge consistently on the high side.
Today after 15 mins apon startup on the freeway... climbs to almost over heat. Turn the motor off allow to cool enough to check fluid in rad. level is fine, over flow tank fine. Start the motor up, head back down the freeway... now no heat for 10 mins. air pocket????? am I doing it wrong or is there a secret here.

I am new here and never have posted on forums before.
The car I bought for my daughter 20 miles outside of town. she needs the car for college (first year). She drives it 90 miles a day just to school.
Please help.. thanx in advance, neither one of us is wealthy..

OK update...... tried again to purge air from system, using an old technic that I used to get the air out of the system..... well no air pocket. also put infrared gun on various locations on the motor. The readings were within 210 fh. BUT... changed the CTS/sending unit again.. after testing ohms impedance. sure the new sensor I replaced 2 weeks ago failed. Yep the guage was not accurate.... that did not explain the vary in temp but the large vacuum leak does (right above the bleeder for the TS housing) when cold no vacuum noise.. engine hot with hood closed.. noticeable. I'm sure it running a bit lean and messing with the PCM and fans had soething to do with this bizar experience. leave it to me to come up with this. Thanx for the data presented to me folks. Poor shame not one reply with everyone on board here,

Sorry for the four month bump but I still have this problem.

The CTS has been replaced. The wiring pigtail for the CTS has been replaced. The relays have all been tested.

I also bought a used temp sensor from morad, and with it plugged in and sitting in a pan of boiling water, the gauge doesn't move. Which means that the sensor he claimed was tested, does not actually work.

Aside from buying another new sensor and replacing it again, I can't think of anything else. Plus, how likely is it that my old one died, and that it's brand new replacement was also defective?

I've had this issue for about 5 months now. ANY help is greatly appreciated.

I'm having this same issue with my 06 grand prix. Both fans only work with a/c on. I have replaced all the relays and new stat. I'll be replacing my temp sensor in am but after looking at your post my spirits are lowered. I checked the wiring aswell. No freys or messed up wiring. GRRRRRRRRRR.
Frustrated big time. I'm sure somebody had this same issue and will help us out.

Originally Posted by jpopdallas

Frustrated big time. I'm sure somebody had this same issue and will help us out.

Don't count on it. I've had this problem for I think about seven months now. I tried everything people suggested with no results, and eventually people just stopped replying. Both in the forums and in PMs.

when you did the intake gasket did you notice if the coolant holes were plugged and was the coolant used dex cool? I've read that air interacts with it and make sludge build up in your system. I have an 06 with only 43,000 and mine started to give wierd temp signes. Looked at my rad cap and damn 1/2 inch of sludge was on the bottom of it. Did a good flush used a super cleaner and fiiled up with non dex-cool and so far all is good.

Originally Posted by jpopdallas

when you did the intake gasket did you notice if the coolant holes were plugged and was the coolant used dex cool? I've read that air interacts with it and make sludge build up in your system. I have an 06 with only 43,000 and mine started to give wierd temp signes. Looked at my rad cap and damn 1/2 inch of sludge was on the bottom of it. Did a good flush used a super cleaner and fiiled up with non dex-cool and so far all is good.

It is dex cool, but it's in really good shape. The coolant passages are fine. The cooling system works great when the car is moving, but it's sitting in traffic when there is no air flow that is the problem. Even worse than sitting is climbing hills at low speeds...

I have the same problem here...my fans will only run when the air conditioner is on and the car is in park...they will not work when the car is driving period...what in the hell is going on here?? i have an 04 gt1...