1969 Chevelle Malibu A/C Pump won't stay on!!!

[redddogg60]

If I jump power from the Battery to the Compressor, it blows nice, cold air. When I remove power from the battery, compressor shuts off (a few months ago pump would stay running after 12v was removed.)

[72chevelleOhio]

So its acting like a low system charge?

[redddogg60]

Yes! But I think it is more electrical related. Are the dash switches a common problem. I don't have any power to the pump.

[rhandwor]

Check from the switch that turns on the pump. If you get no power check that you have power to the switch. Trace it out until you find the problem.

[72chevelleOhio]

Also if its been converted from the old R12, you may want to verify you have the right high and low pressure switches.

[redddogg60]

Yes, it was recently converted to r-134a. Pardon my lack of knowledge on this sort of thing, but where/how do I change the pressure switches. Thanks

[72chevelleOhio]

That was going on the assumption that when someone converted it to R134a, they also replaced the POA valve to a cycling clutch switch. I found this on ebay...poa valve
You may not have the switch(es) if yours was just recalibrated to use R134a.

[rhandwor]

You need to know what the problem is to fix it. If its the pressure switch unplug it and put a jumper on it. If the compressor runs it is either low on refrigerant or the wrong switch. If it ran good last summer I would vote for a low charge.

[redddogg60]

Thanks for all of your great info. Will troubshoot next week. I will post results later.

[72chevelleOhio]

What did you end up finding on this??

[redddogg60]

I believe that the r12 was not evacuated properly(when it was converted to 134A). The compressor kicks on 50% of the time and blows cold. The other 50% of the time you have nothing. When you let pressure off of the high pressure side a cream color "pudding" comes out. I would imagine that I will be replacing the entire system at some point. That's my luck!!!

[redddogg60]

I believe that the r12 was not evacuated properly(when it was converted to 134A). The compressor kicks on 50% of the time and blows cold. The other 50% of the time you have nothing. When you let pressure off of the high pressure side a cream color "pudding" comes out. I would imagine that I will be replacing the entire system at some point. That's my luck!!!

[72chevelleOhio]

I know they make stuff to actually flush the gunk out of the system. I never had to use it so I don't know how it works.

...AF keeps throwing an error whenever I try to respond to your PM....
..I guess I'll try again later...