AC Compressor not Working

[54Rich]

First, I know this has been discussed before, however, the search engine is returing some funky results.

Had an open AC system, repaired it, pulled vacuum and partial charged it. Ran the car the other day and the compressor would not engage. Pulled the connector on it, measured the voltage (It was there) and reinstalled the connector. The compressor would cycle on/off, knew it was low on charge. Shut it off.

Today, decided to finish the charge. But first reset the IAC and the TPS, it was running way too fast. OK, so now the engine is running to spec., however, now I have no voltage to the compressor? Verifyied a charge on the system.

So what determines when the compressor will run? Anyone have an electrical explanation? I can't seem to find a troubleshooting tree for AC electrical.

Thanks,

Rich

 

[Roc87]

Place a jumper in the wires that connect to the low pressure switch and see if there is voltage at the compressor after that.

 

[sbbpwr]

climate control car or manual control?

 

[54Rich]

climate control car or manual control?

Manual control. Unit was replaced, the vacuum switch was broken.

Is the low pressure switch off the condensor?

Thanks,

Rich

 

[Roc87]

Yep, its on the condenser/drier. Just pull the two wire plug off it, and then put in a paperclip or a small wire. If there isn't enough pressure in the system, the compressor won't come on. Always have to jump that connector when filling/adding to a low system.

Let us know how it works out.

 

[54Rich]

Yep, its on the condenser/drier. Just pull the two wire plug off it, and then put in a paperclip or a small wire. If there isn't enough pressure in the system, the compressor won't come on. Always have to jump that connector when filling/adding to a low system.

Let us know how it works out.

Thanks, Jumped it and it comes on. I really don't know a lot about AC systems, except what it says on the bottle. Shows 40 psi on the low side at 63 F outside temp. It does not appear to be blowing cold I have put in 1 1/2 cans HC12A from here:

HC12a Auto Refrigerant HC12aUSA.com

Copied from the website:

HC-12a® requires 35% of the CFC R12 charge by weight
• HC-12a® requires 40% of the HFC R134a charge by weight 6oz can = 17oz of CFC R12 and 15oz of HFC R134a

I don't have the proper adapter for the high side, gauges are for a 134R system.

Any ideas? I appreicate the help so far.

Thanks,

Rich

 

[Roc87]

a couple quick questions. How long was the system opened before repair? Did you replace the drier? If not that may be full of water, there is something in those things that eliminates the humidity, and if left opened they can become bad. Did you replace the oriface tube (Small thing that goes inside one of the lines to the condenser)? Also, how long did you leave the system in a vaccuum? I'm not used to doing anything with R12, but I like to have around 40psi on the low side with R134. What's the high side running? The electric fan(s) are running, correct?

 

[54Rich]

a couple quick questions. How long was the system opened before repair? Did you replace the drier? If not that may be full of water, there is something in those things that eliminates the humidity, and if left opened they can become bad. Did you replace the oriface tube (Small thing that goes inside one of the lines to the condenser)? Also, how long did you leave the system in a vaccuum? I'm not used to doing anything with R12, but I like to have around 40psi on the low side with R134. What's the high side running? The electric fan(s) are running, correct?

No idea of how long it was open, I'd say a long time. I replaced the compressor (Used), the condenser, the orifice tube. Ran a vacuum on the system for 20 to 30 minutes. Held vacuum just fine. The fan is NOT running. Not sure of the high side, I don't know where to get the adapter from a R12 to a 134 gauge to hook up the high side.

Thanks,

Rich

 

[Roc87]

For now, I'd say find out why the fan isn't coming on. Without it cooling the condenser (part in front of radiator) it is probably causing the high side to be too high. You could try running some water from the garden hose over the condenser to cool it and see if it starts blowing cooler air.

 

[54Rich]

More Observations

For now, I'd say find out why the fan isn't coming on. Without it cooling the condenser (part in front of radiator) it is probably causing the high side to be too high. You could try running some water from the garden hose over the condenser to cool it and see if it starts blowing cooler air.

OK, the fan does come on, don't know how I miss that. Anyhow, with the low switch bypassed and the compressor and fan running, the tube after the orifice gets frosty cold. However, with the system off, engine off, I have 40 psi on the low side. When the system is on, running, I do not get much of a reading? So do you check the low side running? If that's the case I do not have enough charge.

Also, I think the heater valve is not working and I'm heating the air as I cool it

What position is the heater valve in when the engine is running and the heater is off. Mines in the up position always, never moves.

Getting closer, I think

Thanks,

Rich

 

[54Rich]

Another interesting fact

When I go to heat, the car idles with no issues, very smooth and a definite difference from off or AC. Idle is normaly a bit choppy

Vacuum leak?

Rich

 

[Roc87]

With the fan running & car running w/ ac on, I usually get between 35-40psi low side, so yours sounds like it needs some more.

Don't know about the vacuum leak deal causing idle to be rough....

 

[54Rich]

With the fan running & car running w/ ac on, I usually get between 35-40psi low side, so yours sounds like it needs some more.

Don't know about the vacuum leak deal causing idle to be rough....

Added more, seems to be working fine:biggrin: Except for the bad heater control valve, just another part oh and the oil fogger turbo But at leats I can roll up the windows

Appreicate your help!

Thanks,

Rich

 

[Roc87]

Hey, well at least the oil fogger turbo will keep people from tailgating