1994 GT Cooling Issue

[wnyman10]

before ya swap that, I would make sure the fan is going into high speed mode and not just stuck in slow.

how do you check that

 

[wnyman10]

So maybe just maybe I found the problem

I ran the car till it got about part way up the gauge and an turned the ac on, No fan weird. Turned the ac off and sure enough it started creeping until the fan went on full blast. Then I did some searching and found if you unplug the temp sensor the fan should always be on, on low. Unplugged that started the car and no fan took my chances with a really long screw driver and pushed the blade on the fan and sure enough it went, it was at operating temp so i plugged the sensor back in and then started it again. No fan so i pushed the blade and the fan went and stayed running keeping the car right dead in the middle. So I'm not expert in automotive electrical by any means so don't judge but could that mean the fan motor is gone and getting less power when the low circuit flips and when i push it it gets going, but it gets more power when the high circuit flips and that's enough power to get it going. Otherwise I cant explain why I have highspeed fan but no low speed but pushing the blades gets me low speed. If the circuit was screwed it just wouldn't work or no?

 

[ttocs]

it may not be the fan as much as the ccrm, or even just the fuses that feed it. I Assume you inspected all the fuses under the hood?

 

[wnyman10]

Yup all the fusses are good, I did a diagnostic check and the low speed and high speed come on, I have no fan with defrost and ac which I believe you have at any temp. The high speed comes on when it gets real hot but just for a minute or 2 and shuts off.

 

[cobrajeff96]

Might be the brushes/commutator is overly worn and can't get going initially. Could always test with a new fan motor (though I'm not sure they sell only the motor any more) but it's always good to have another one even if it's not the culprit, if you plan to keep the car for a really long time. You'll have a spare.

There is a separate low speed fan logic apart from the high speed in the CCRM relay box. There's a series of tests you can do and maybe that'll help isolate the fault. (attached)

I believe these are for modular era CCRMs so use them as a reference only. I'd recommend using the power of El Goog to search for 94/95 era troubleshooting schematics and procedures.

 

[wnyman10]

Does anyone know if you put the defrost on full blast or the ac to max does the electric fan always come on? or does the car have to be operating temp first?

I believe its supposed to be on at anytime the defrost or the ac is on. If that's the case I think my CCRM is pooched cause I've replaced everything else.

 

[GTamas]

.

 

[cobrajeff96]

I'm honestly unsure whether the hi fan is supposed to come on by default just from turning the A/C dial to Norm/Max/Defrost or if it comes on as a result of being actively monitored by the pressure switch on the high side. I would think it's the pressure switch, otherwise why have one aside from just saving the compressor from nuking itself when it gets too hot and/or too pressurized?

 

[wnyman10]

Solved!!!!! It was the CCRM, I replaced it today and the fan went to low in the middle of the gauge and it now sits happily right in the middle as it should never went over after an hour of driving.

 

[cobrajeff96]

Tight.

 

[wnyman10]

Huge thanks to everyone would have never got it solved without you guys.

 

[Daryl]

How old's the radiator and pump?

You can try doing an electrolysis test, pretty easy to do.

Sidebar: cobrajeff… very nice info and something I never knew of. Also, would never have known that a voltmeter could read an electrolysis test in fluid. But, now that I know I will test mine for peace-of-mind.

Can the test be done when the coolant is cold or does it have to be at operating temperature?

 

[cobrajeff96]

I would think you'd want to perform the test cold. But you might also gain info testing hot as well, but just be careful. Have the cap off from the start.