AC/Heater Temp sensor loaction 0n 94 vette
04-18-2019, 06:34 PM
#1
AC/Heater Temp sensor loaction 0n 94 vette
My AC Runs on low blower speed a few seconds after starting car. Control head is then locked up will not respond till key is turned of and on again. After about 10 seconds blower comes on and control locks again. Heater will not work. Only AC. Engine cooling fan comes on with activation of the blower motor even with engine cold. (AC runs on low blower speed even with AC/Heater control head unplugged and removed)
Cleaned contacts in control head. No Change. Switched blower control module in blower motor box with one from another car that is working fine. No change.
It appears the system searches for internal temp before activating AC and low blower speed.
Is this a symptom of Body Control Module failure?
Cleaned contacts in control head. No Change. Switched blower control module in blower motor box with one from another car that is working fine. No change.
It appears the system searches for internal temp before activating AC and low blower speed.
Is this a symptom of Body Control Module failure?
04-20-2019, 11:08 PM
#3
I am going to check that next. Have another car that everything seems to work on. Will probably swap it out and see if that changes anything. I have run diagnostic with heater/ac control doesn't show any codes. All buttons function for about 20 to 30 seconds then blower switches to low on its own. The none of the control head buttons will work till key is switched off for a few seconds and back on.
04-21-2019, 01:56 AM
#4
The rear defroster button stops working as well. I was starting to think it was the Heater/AC module after I saw a kit from BATEE.COM that has replacement resistors and capacitors in it for the module. I had already cleaned the contacts in the control head with no change in the problem.
I knew the PCM wasn't the problem. I tried another one I had. And I ask a electronics repair man about the BCM and he doubted that was causing the problem. All that I had read about BCM issues usually triggers a system error on the dash LCD display. I pulled the BCM fuse out and a got a system error in the display so I felt pretty sure the BCM was working.
I didn't know where the module was located, but figured it would be hard to get to. Everything else is. LOL. I am also assuming the Heater/AC control head and the Heater/AC module are matching pairs. So buying a used one would mean getting both parts out of a donor car. If I buy the kit from BATEE.com I will probably pull the module and have an electronics tech put it in.
If and when I get the problem resolved I will post my results for the next guy or gal. LOL
I knew the PCM wasn't the problem. I tried another one I had. And I ask a electronics repair man about the BCM and he doubted that was causing the problem. All that I had read about BCM issues usually triggers a system error on the dash LCD display. I pulled the BCM fuse out and a got a system error in the display so I felt pretty sure the BCM was working.
I didn't know where the module was located, but figured it would be hard to get to. Everything else is. LOL. I am also assuming the Heater/AC control head and the Heater/AC module are matching pairs. So buying a used one would mean getting both parts out of a donor car. If I buy the kit from BATEE.com I will probably pull the module and have an electronics tech put it in.
If and when I get the problem resolved I will post my results for the next guy or gal. LOL
If switching the control heads doesn't do anything, switch the control MODULEs. It's up above the accelerator pedal. Absolutely not easy. Very fussy.
What does the rear window defroster do? Does it shut off after 10 seconds too? The rear defroster relay is controlled by the HVAC module like most of the other HVAC functions. If the defogger is acting up too, could be the control module.
The CCM / BCM has nothing to do with HVAC.
What does the rear window defroster do? Does it shut off after 10 seconds too? The rear defroster relay is controlled by the HVAC module like most of the other HVAC functions. If the defogger is acting up too, could be the control module.
The CCM / BCM has nothing to do with HVAC.