: R-134 upgrade, A/C only works on Defrost

TC Caddguy
08-29-07, 11:31 PM
1988 F/B - AC quit working - took to local shop - he converted
the R-12 to R134, and now it only cools with it on defrost.

Any suggestions ?

Thank You - Paul, TC Caddyguy

08-30-07, 05:39 PM
Yeah, take it back and make him him fix it.

08-30-07, 08:10 PM
I had that exact same problem when I got my Olds AC converted. The mechanic said he didn't cover the controls since his job was only to fix the components. Some possibilities could include the automatic door that sends heat to the floor and cooling out the vents; it may be stuck. However that would be the case if "AUTO" blew cold air to the floor. If "AUTO" blows out the dash, but does not engage the compressor, then you have a wiring/electric issue. The compressor is not coming on when it should. That could either be the mechanics fault, re-wiring the compressor (if he touched it), or the age of the console in your dash. For the mechanical consoles, little vacuum lines leaked causing the settings to flip back and forth. For more modern electric ACs, simple wires may be to blame, especially in old GM cars.