HVAC control head or relay
07-28-2018, 07:47 PM
#1
Thread Starter
HVAC control head or relay
Car has been running flawlessly for a couple years, and AC worked well when parked a week ago. Went to turn on the AC this morning after going to the AZ PCA Mountain region Cars and Coffee at the Prescott Panera Bread Co. No fan on any of the 4 speed levels. AC button doesn't light up, nor turn on the compressor or cool the sweating passengers. Defroster fan works at full blast.
Got home and pulled relay X (HVAC) and swapped in relay XII (horn). Nothing changed....AC still borked. I'll order more 52 relays (calling ROG).
What's next? AC control head relay repair/new controller?
Thanks in advance!
Brian
Got home and pulled relay X (HVAC) and swapped in relay XII (horn). Nothing changed....AC still borked. I'll order more 52 relays (calling ROG).
What's next? AC control head relay repair/new controller?
Thanks in advance!
Brian
07-29-2018, 12:17 AM
#2
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Check fuses. The blower not running is different from compressor not running.
What did did you work on last? Anything in the console? Edge connector on the control head forward left is dedicated to the blower. The resistor pack under the cowl has a single connector. The motor itself has a single connector. Any are possible failure points but generally don’t fail without help.
What did did you work on last? Anything in the console? Edge connector on the control head forward left is dedicated to the blower. The resistor pack under the cowl has a single connector. The motor itself has a single connector. Any are possible failure points but generally don’t fail without help.
07-29-2018, 10:46 AM
#3
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Check fuses. The blower not running is different from compressor not running.
What did did you work on last? Anything in the console? Edge connector on the control head forward left is dedicated to the blower. The resistor pack under the cowl has a single connector. The motor itself has a single connector. Any are possible failure points but generally don’t fail without help.
What did did you work on last? Anything in the console? Edge connector on the control head forward left is dedicated to the blower. The resistor pack under the cowl has a single connector. The motor itself has a single connector. Any are possible failure points but generally don’t fail without help.
It sticks in my head that you can get to that by only removing the carpeted side panel (drivers side) of the console. Look up and to the side of the HVAC Controller.
Edit: If your 928 is a 91 or newer (can't recall at the moment) I have the proper replacement relay that is a direct internal replacement without any hack job of adding an external relay etc.
Hope that helps,
Dave
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07-29-2018, 03:34 PM
#4
Thread Starter
Dr. Bob and DR. Thanks for the response.
I haven't been fixed anything on the car in a couple years, other than oil change in February. I did have to replace the CE panel about 2 or 3 years ago due to bad short/small electrical fire (don't use cheap ORielly fuses!) and replaced all fuses and relays with new from Roger at that time.
I haven't been into the central console in years. Stereo was replaced over 4 years ago. Central HVAC controller acted up 4 years ago in a similar fashion, I took it out, plugged it back in then it worked (loose connection?).
This morning: Checked all fuses related to HVAC and blower. All test good. Put relay from X in XII position. Horn works. Put relay XII back in XII horn works. So relay X and XII must be good. Started the car. Still no fan on all 4 positions. Defroster comes on full blast when slid over as before. AC button doesn't light up, nor does the compressor engage when depressed. After lunch I'll pull the console and check connections on the rear of HVAC control and AC button. If those are good and no love, then controller is bad?
Thanks again!
I haven't been fixed anything on the car in a couple years, other than oil change in February. I did have to replace the CE panel about 2 or 3 years ago due to bad short/small electrical fire (don't use cheap ORielly fuses!) and replaced all fuses and relays with new from Roger at that time.
I haven't been into the central console in years. Stereo was replaced over 4 years ago. Central HVAC controller acted up 4 years ago in a similar fashion, I took it out, plugged it back in then it worked (loose connection?).
This morning: Checked all fuses related to HVAC and blower. All test good. Put relay from X in XII position. Horn works. Put relay XII back in XII horn works. So relay X and XII must be good. Started the car. Still no fan on all 4 positions. Defroster comes on full blast when slid over as before. AC button doesn't light up, nor does the compressor engage when depressed. After lunch I'll pull the console and check connections on the rear of HVAC control and AC button. If those are good and no love, then controller is bad?
Thanks again!
07-29-2018, 03:47 PM
#5
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Hi Brian,
You are very welcome!
Definitely check the A/C Switch connector also, it is located directly behind the switch on the backside.
Dave
You are very welcome!
Definitely check the A/C Switch connector also, it is located directly behind the switch on the backside.
Dave