a/c low pressure switch
09-25-2009, 10:03 PM
#16
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Thread Starter
Tampa............the compressor is a new rebuilt Porsche unit with new hoses and O-rings, new rxr/drier and new expansion valve with new O-rings.
I've electrically tested the Freeze switch...........from what I can see its good.
The issue is now time related..............initially after getting the system together and charged it worked great.
Now the compressor engages less and less as the system is used.............sure its one of 3 switches or the relay.............I'll jumper all 3 but I'm betting on the relay being bad.
I've electrically tested the Freeze switch...........from what I can see its good.
The issue is now time related..............initially after getting the system together and charged it worked great.
Now the compressor engages less and less as the system is used.............sure its one of 3 switches or the relay.............I'll jumper all 3 but I'm betting on the relay being bad.
09-25-2009, 10:32 PM
#17
Race Car
When it fails just do one at a time, get a little jumper wire made up ahead of time. Your sure your pressure is OK, if your in doubt and bypass the switch don't leave it connected for too long. The head relay is pretty small and you maybe correct but I would get the other areas out of the way first. I guess you don't have a spare head to try, do you have the WSM on how to test the whole system?
09-26-2009, 02:00 AM
#20
Chronic Tool Dropper
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Malcolm--
The low voltage at the freeze switch points to the control head relay as your problem. Don't bother jumpering the other switch in the circuit (the low pressure switch in the high pressure plumbing). Checking voltage at the freeze switch isolates the problem nicely to that relay.
There are a few good writeups on the relay upgrade. Mine was done in 1998 or so as simple documentation of what I did for my own car, but I used a relay from a local non-R-S store. Since then there have been several who have used a Radio Shack DPDT relay with success. Same instructions apply, but the relay pins are different.
I had a discussion with Roger at the OCIC about a replacement relay that could live right by the freeze switch. I need to get on with that project, but figgered that it would need to be firmed up by next spring. Whooda thunk that a krazy kanuck would need AC in September???
The low voltage at the freeze switch points to the control head relay as your problem. Don't bother jumpering the other switch in the circuit (the low pressure switch in the high pressure plumbing). Checking voltage at the freeze switch isolates the problem nicely to that relay.
There are a few good writeups on the relay upgrade. Mine was done in 1998 or so as simple documentation of what I did for my own car, but I used a relay from a local non-R-S store. Since then there have been several who have used a Radio Shack DPDT relay with success. Same instructions apply, but the relay pins are different.
I had a discussion with Roger at the OCIC about a replacement relay that could live right by the freeze switch. I need to get on with that project, but figgered that it would need to be firmed up by next spring. Whooda thunk that a krazy kanuck would need AC in September???
09-26-2009, 02:58 AM
#21
Electron Wrangler
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Food for thought: The center vent contains a micro-switch. When the center vent is manually closed, the micro-switch is engaged and adjusts the flap step-motor. The step-motor adjusts flaps within the HVAC box and directs the air accordingly. Insufficient airflow over the evaporator coil may cause freezing; especially if mixed with cooler outdoor Alberta air. These flaps may sometimes require adjustment.
Alan
09-26-2009, 12:16 PM
#22
Rennlist Member
Thread Starter
The low voltage at the freeze switch points to the control head relay as your problem. Don't bother jumpering the other switch in the circuit (the low pressure switch in the high pressure plumbing). Checking voltage at the freeze switch isolates the problem nicely to that relay.
There are a few good writeups on the relay upgrade. Mine was done in 1998 or so as simple documentation of what I did for my own car, but I used a relay from a local non-R-S store. Since then there have been several who have used a Radio Shack DPDT relay with success. Same instructions apply, but the relay pins are different.
Given the weather swings of late we'll be complaining about snow soon.............hate to even type that 4 letter word.
