A/C Low Pressure Switch, hmmmmmm?
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Team Owner
Joined: Mar 2000
Posts: 83,383
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From: Boston, MA
A/C Low Pressure Switch, hmmmmmm?
So I pick up MT0207 ($17.99) from Autozone, which their website stated was for R134a for an '87 Vette.
The package reads....
"R12 Adjustable Cycling Switch, Fits General Motors Models 79-93 and Volvo 83-91"
...maybe I should go and select R12 and see if it comes back with something different.
**EDIT**
Yep... R12 comes back with part 35751 for $10.99.
The package reads....
"R12 Adjustable Cycling Switch, Fits General Motors Models 79-93 and Volvo 83-91"
...maybe I should go and select R12 and see if it comes back with something different.
**EDIT**
Yep... R12 comes back with part 35751 for $10.99.
Le Mans Master
Joined: Jan 2006
Posts: 8,246
Likes: 114
From: Watkins Glen NY
So, If I read this right, the low pressure switch is specific to 12 or 134?
That might explain the problem with my switch not working after converting to 134? System is fully charged and works fine, but I have to bypass the low pressure switch with a jumper. Worked fine last year with the R-12, but not now with a compressor/drier change and a recharge with R-134.
That might explain the problem with my switch not working after converting to 134? System is fully charged and works fine, but I have to bypass the low pressure switch with a jumper. Worked fine last year with the R-12, but not now with a compressor/drier change and a recharge with R-134.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
AC Delco !5-1122 - used in everything from '80 to about '93. The only difference between what's being marketed as an R134 switch and an
R12 switch is the cutoff threshold for R134 is set at 22.5 psi and for
R12, 25psi (and that's because R134 reaches 32 degrees a couple pounds lower than R134). ONLY, the last OEM switch I bought was set at 22.5 psi and I didn't bother to check it until my outlet tube was making ice cubes! Of course it was adjustable, so I removed the harness and turned the screw between the terminals clockwise a half turn at a time and viola - I put it right at 25 psi! You can too - regardless of what you buy - as long as it's adjustable and it may not be a bad idea to check it regardless of the advertising. If it needs to go down, turn the screw counterclockwise. First, get it blowing at max and then pull the blower connector and the lack of air across the core will cause the pressure to drop and once it does, note what the pressure is when the compressor cuts off. Adjust from there - 22.5 psi for R134; 25 psi for R12. The only other advantage I can think of is that the so called R134 switch might just include an o-ring that's compatible with that gas. The A/C Delco I bought had a black o-ring and that's suppose to mean R12, but even though I stuck with R12, I swapped all my o-rings out for Blue, which is compatible with anything.
R12 switch is the cutoff threshold for R134 is set at 22.5 psi and for
R12, 25psi (and that's because R134 reaches 32 degrees a couple pounds lower than R134). ONLY, the last OEM switch I bought was set at 22.5 psi and I didn't bother to check it until my outlet tube was making ice cubes! Of course it was adjustable, so I removed the harness and turned the screw between the terminals clockwise a half turn at a time and viola - I put it right at 25 psi! You can too - regardless of what you buy - as long as it's adjustable and it may not be a bad idea to check it regardless of the advertising. If it needs to go down, turn the screw counterclockwise. First, get it blowing at max and then pull the blower connector and the lack of air across the core will cause the pressure to drop and once it does, note what the pressure is when the compressor cuts off. Adjust from there - 22.5 psi for R134; 25 psi for R12. The only other advantage I can think of is that the so called R134 switch might just include an o-ring that's compatible with that gas. The A/C Delco I bought had a black o-ring and that's suppose to mean R12, but even though I stuck with R12, I swapped all my o-rings out for Blue, which is compatible with anything.
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Scorp, go to ac-delco's website. You can punch in other mfg's part numbers in there and find the ac-delco number, and check for all makes and models it fits. Also has picture for most parts. You need to navigate a bit to get there.
