A/C Question (1 Viewer)

Joined
Apr 4, 2009
Messages
95
Location
Tucson , Arizona
It's been a while since the 80 completely stumped me. But here is the issue:

A/C performance has been mediocre most summers here in AZ. But then the compressor started to cut off for no good reason but would mostly come back on when cycling the A/C switch (no overheating issue). Then it died altogether. I tested the clutch and worked fine. Read up on some MUD threads and replaced the pressure switch. Recharged system and all worked superbly for exactly 2 days. But after 2 days all dead again. The weird thing is that by chance I discovered that the clutch will engage and cold air will blow ONLY with the defrost button on but NOT with the any other modes.

Any suggestions??
 

Hornd

SILVER Star
Joined
Dec 18, 2013
Messages
2,599
Location
Toledo, OH
Take it to a shop and they will put gauges on it - need to know charge level.
AC has a high pressure side so unless you know what your doing it is job for a Technician.
1601242055503.jpeg
 
Joined
Apr 4, 2009
Messages
95
Location
Tucson , Arizona
I did when it was all dead. Coolant volume/pressure was not the issue. They wanted $160 for further diagnosis and keep it for a few days. Needed vehicle...
 
Joined
May 26, 2005
Messages
7,919
Location
Phoenix
It's been a while since the 80 completely stumped me. But here is the issue:

A/C performance has been mediocre most summers here in AZ. But then the compressor started to cut off for no good reason but would mostly come back on when cycling the A/C switch (no overheating issue). Then it died altogether. I tested the clutch and worked fine. Read up on some MUD threads and replaced the pressure switch. Recharged system and all worked superbly for exactly 2 days. But after 2 days all dead again. The weird thing is that by chance I discovered that the clutch will engage and cold air will blow ONLY with the defrost button on but NOT with the any other modes.

Any suggestions??
Sounds like a problem in the dash control unit. While it might technically be possible to find the issue and repair it, I'd be looking for a spare. Maybe you have a friend that would let you borrow theirs for testing? Or maybe you can find a used one cheap enough that it wouldn't be a big loss if it didn't fix the problem.

Along with the control unit, there might be some kind of ECU for the A/C that I vaguely remember.
 
Joined
Apr 4, 2009
Messages
95
Location
Tucson , Arizona
Sounds like a problem in the dash control unit. While it might technically be possible to find the issue and repair it, I'd be looking for a spare. Maybe you have a friend that would let you borrow theirs for testing? Or maybe you can find a used one cheap enough that it wouldn't be a big loss if it didn't fix the problem.

Along with the control unit, there might be some kind of ECU for the A/C that I vaguely remember.

Got a clean one on e-bay an just put it in. All is functional again. Hoping nothing else pops up. Thanks for the suggestion. Definitely a "why didn't I think of that" moment.
 

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