82 camaro. LG4. Had the system retroffited last year to R134a. Worked great last year. This year nothing is happening. I checked the pressure in the system and it is right on the money. The compressor is not turning. I checked the voltage to the compressor plug and on max cool it is reading between .14 and .54 volts. Is this right? Sounds really low. The fuse is fine.

Any thoughts would be great. It is freakin hot and I love my AC.

Thanks
Dean

 

My problem was the power steering pressure switch. Try removing that connector and jumpering the wires to see if the clutch engages. If that doesnt work, you can move to the low pressure switch in the accumulator. Do the same thing, remove the connector and jumpter the wires. If either of these two tips fixes the problem, that switch is bad (try the steering switch first). I plan to just leave the steering switch out of the loop at the moment.

 

Thanks for the reply. What do you mean by power steering switch? do you mean the 2 wire connector that goes to the AC compressor?

Sorry I am not much on knowing how AC works or its components.

Thanks

 

On Montes, there's a switch mounted in the high pressure power steering line that cuts power the the A/C clutch when you go full lock on the steering wheel as to not bog the engine. The F-body high pressure line that I'm running now also had that, now that I think about it (just made me think that I can just replace it with my old switch from the Monte lines; thanks for making me brings that up ).

 

What do you mean?

With the compressor not running, the pressure in the system should always be the equilibrium vapor pressure of the refrigerant at whatever the temp is; one might expect to see something around 60-80 psi with R-134A.

What exactly was the pressure?

 

I checked the pressure with the car running, AC on MAX and fan all the way up. I have one of those gauges that I got with the refrigereant. It says between 25-45 is a charged system. Mine was right at 45.

I am stumped. I can't find the power steering switch the person above mentioned. I am guessing at this point the compressor is frozen.

If you have any other ideas, I am up to trying.

Thanks

 

Your system has no refrigierant. That's why the compressor isn't coming on.

The 25-45 psi is for a RUNNING SYSTEM. When it's running, the compressor is hard at work sucking refrigerant out of the low side and pumping it into the high side; you'd expect to see low pressures like that on the low side, and 250psi sort of numbers on the high side. if the compressor is NOT RUNNING, then you should see the refrigerant's equilibrium vapor pressure (which is the pressure that the evapration of the substance will produce of left in a closed container.... it's a fundamental characteristic of any given substance) on BOTH sides; which I believe is somewhere in the 60-80 psi range for R-134A at typical summer temps.

You're only seeing 45 psi in a NON-RUNNING system. That means the system is COMPLETELY DEVOID OF refrigerant. There aren't even enough molecules of it left in there to bring it up to the equilibrium vapor pressure.

Fix the leaks, evacuate it, and re-charge it.

There's probably nothing wrong with the compressor or the switches. You can verify that the compressor actually works, by unplugging the plug with green wires in it, that goes to the low pressure cutoff switch on the side of the accumulator/dryer; and jumpering between the 2 terminals in the plug with a paper clip or something; and turning the AC on for a few seconds. The compressor should run. Don't leave it running like that for more than a few seconds. If it does run, then that means that everything in your system is doing what it's supposed to, except for whatever it is that leaks.

Incidentally, if you have a V8 car, it shouldn't have a switch on the power steering line. Only the low pressure cutoff switch on the accumulator.

 

Sofakingdom thanks for your help. I jumpered the low side switch and the compressor came on! So does this definetly mean I have no refrigerant? I am confused because when I plug the gauge in the low side the needle on the gauge goes to the DANGEROUS section on the scale. When I pull the trigger to add the FREON the gauge dumps to near 0. So should I be going by when I pull the trigger and the refrigerant is going in? or just when the gauge is hooked?


Thanks alot for your help.

 

Definitely, yes.

The reason the gauge reads high when you start, is because the compressor is NOT RUNNING. Remember, in an operating AC, the compressor is sucking as hard a sit can (reducing the pressure) on the low side, while it's trying to put all the Freon into the high side. The only Freon that exists on the low side in a running unit is what liquid has passed through the orifice, evaporated, expanded and coled, and been warmed by the hot interior air passing over the evaporator coil. If it's not running, then none of this is happening.

I have no clue about "pull the trigger" and all that, I use a gauge set with valves.

I'd suggest finding and fixing the leaks before putting more refrigerant in it; and evacuating the system also, in case there's water vapor or other contaminants in it.

 

wheres the low side port? im trying to do mine