Need A/c Help

[Sj92stanger]

car was converted to 134a, it blows cold and is properly charged but compressor only kicks on with switch pigtail jumped. So I bought a 134a pressure switch, but it doesn't seal good even with a new o-ring and leaks, the old one seals right up. so my question Is does the dryer also get an adapter like the low/high fittings? thanks guys

 

[jrichker]

The original low pressure cutout switch is adjustable...

Freeze 12 & R134 Low pressure cutout switch adjustment.
The low pressure cutout switches are adjustable. They should be set with the low limit about 18-21 PSI, the stock setting is about 25 PSI. Remove the wiring connector and there is a screw slot in between the connector pins. Turning it clockwise increases the trip pressure where it cuts off and counterclockwise decreases the trip pressure. I believe that each 1/4 turn counterclockwise lowers the cutoff pressure by 1 PSI.

 

[RaggedGT]

If tuning the old
Pressure switch doesn't work I'd replace the dryer.