Another blower motor not working, maybe a bad HVAC controller?
10-08-2022, 03:41 PM
#1
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Location: Webster, NY ( near Rochester, NY)
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Another blower motor not working, maybe a bad HVAC controller?
I have read most of the threads on the subject and have not found similar symptoms ( or I haven’t found any yet).
1985S with 74k miles.
Background
About a year ago the blower fan would just turn on high for no reason. ( I know why) Likely a resistor replacement or an internal resistor wire issue. I have one to replace it but have not yet.
Last year I was able to pull the plug on the resistor pack and test each port on the plug, moving the control lever and all seemed to have power as I moved the HVAC fan switch.
This year, however, my HVAC control switch will not work at all and neither will my AC button ( no defrost or any other position). And testing the plug this year, revealed that I was not getting power to the plug in any position.
I started by replacing blower motor relay X-10 and HVAC blower fuse 17 ( actually twice just to make sure). I also replaced the defrost relay VIII-8 as well and the HVAC Controller fuse 8 as well.
I unplugged the blower motor and tested it with a separate power source and it did not work. A separate new problem that I will have to solve.
I pulled the blower motor relay out and tried to jump the 30 and 87 port and still no blower motor.
Is there anything else I should be testing before I remove the Controller and if and when I do, what am I looking for? I understand that there is an Associated relay that may also go bad in that as well.
I was hoping to fix this before winter storage if possible.
Thanks in advance.
Don
1985S with 74k miles.
Background
About a year ago the blower fan would just turn on high for no reason. ( I know why) Likely a resistor replacement or an internal resistor wire issue. I have one to replace it but have not yet.
Last year I was able to pull the plug on the resistor pack and test each port on the plug, moving the control lever and all seemed to have power as I moved the HVAC fan switch.
This year, however, my HVAC control switch will not work at all and neither will my AC button ( no defrost or any other position). And testing the plug this year, revealed that I was not getting power to the plug in any position.
I started by replacing blower motor relay X-10 and HVAC blower fuse 17 ( actually twice just to make sure). I also replaced the defrost relay VIII-8 as well and the HVAC Controller fuse 8 as well.
I unplugged the blower motor and tested it with a separate power source and it did not work. A separate new problem that I will have to solve.
I pulled the blower motor relay out and tried to jump the 30 and 87 port and still no blower motor.
Is there anything else I should be testing before I remove the Controller and if and when I do, what am I looking for? I understand that there is an Associated relay that may also go bad in that as well.
I was hoping to fix this before winter storage if possible.
Thanks in advance.
Don
Last edited by Donpny; 10-08-2022 at 03:47 PM. Reason: More info.
10-09-2022, 12:58 AM
#2
Rennlist Member
The pins inside of the small molex connectors for the HVAC control head can sometimes burn up from corrosion or corrosion just causing a bad connection.
My 81 did the same thing with the HVAC head doing nothing like it wasn't getting power and it turned out to be a wire in one of the molex connectors being burnt up.
A new pair of spade connectors to bypass it and it was fine ever since.
To see this you will have to pull the control head out and the carpet panels on the sides of the center console to get easy access.
It could also just simply be a bad ground so you may as well clean the ones one the steering column and above the CE panel.
My 81 did the same thing with the HVAC head doing nothing like it wasn't getting power and it turned out to be a wire in one of the molex connectors being burnt up.
A new pair of spade connectors to bypass it and it was fine ever since.
To see this you will have to pull the control head out and the carpet panels on the sides of the center console to get easy access.
It could also just simply be a bad ground so you may as well clean the ones one the steering column and above the CE panel.