95 GT Running very hot
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Joined: Nov 2007
Posts: 1
95 GT Running very hot
Gentlemen please help!
I've posted about this problem on other forums and received great help..almost narrowed down the cause:
My 95 GT is running very hot: Radiator and thermostat are new. No problems with heater core, or water pump...hardware is OK and coolant is circulating as it should. The
problem was narrowed down to the cooling fan not turning on:
Cooling fan runs on low speed when temp is very high (208F+).
Cooling fan DOES NOT run when Max A/C is turned on...as it should.
Further diag of CCRM revealed that EDF and HEDF relays appear to be fine since when ground / voltage are applied to control side of both relays the fan DOES RUN at right
speeds as was done in this test:
When ground is applied to pin 17 (Light Green) high speed fan truns on OK...to me this indicated that High-Speed HEDF relay is fine
When car is very hot (past L of NORMAL) pin 14 (Dark Blue) has current and low speed fan runs OK..to me this indicated that Low Speed EDF relay is fine.
So...since the relays are ok...are these assumptions correct:
1. In the above circuit Powertrain Control Module (PCM) decision-making-steps are not grounding 14 (Dark BLue) when Max A/C is truned on (because fan should run at high speed
when Max A/C is on...which it does not)
2. Powertrain Control Module (PCM) is supplying 12V only when car is very hot to turn low speed fan (this may be by design per earlier post---low speed fan turn on 208*F+ )
3. If Powertrain Control Module (PCM) thinks that for whatever reason the fan should not be on.....is it correct for me to assume that a sensor of some sort or other is
feeding PCM wrong info thats involved info PCM's decision making process as to wether or not to turn the fan on? .. in which case I can troubleshoot the sensors involved.
4. Is it possible that it's the A/C High pressure Cutout / Fan swithc in the above diagram?
Any pointers would me much appreciated....this puzzle is almost solved
I've posted about this problem on other forums and received great help..almost narrowed down the cause:
My 95 GT is running very hot: Radiator and thermostat are new. No problems with heater core, or water pump...hardware is OK and coolant is circulating as it should. The
problem was narrowed down to the cooling fan not turning on:
Cooling fan runs on low speed when temp is very high (208F+).
Cooling fan DOES NOT run when Max A/C is turned on...as it should.
Further diag of CCRM revealed that EDF and HEDF relays appear to be fine since when ground / voltage are applied to control side of both relays the fan DOES RUN at right
speeds as was done in this test:
When ground is applied to pin 17 (Light Green) high speed fan truns on OK...to me this indicated that High-Speed HEDF relay is fine
When car is very hot (past L of NORMAL) pin 14 (Dark Blue) has current and low speed fan runs OK..to me this indicated that Low Speed EDF relay is fine.
So...since the relays are ok...are these assumptions correct:
1. In the above circuit Powertrain Control Module (PCM) decision-making-steps are not grounding 14 (Dark BLue) when Max A/C is truned on (because fan should run at high speed
when Max A/C is on...which it does not)
2. Powertrain Control Module (PCM) is supplying 12V only when car is very hot to turn low speed fan (this may be by design per earlier post---low speed fan turn on 208*F+ )
3. If Powertrain Control Module (PCM) thinks that for whatever reason the fan should not be on.....is it correct for me to assume that a sensor of some sort or other is
feeding PCM wrong info thats involved info PCM's decision making process as to wether or not to turn the fan on? .. in which case I can troubleshoot the sensors involved.
4. Is it possible that it's the A/C High pressure Cutout / Fan swithc in the above diagram?
Any pointers would me much appreciated....this puzzle is almost solved
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mrmrultimate
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Sep 10, 2015 09:43 AM
