Troubleshooting Air Conditioning in 86 Aries with 2.2l

[1987dodgearies]

Thank you for the information. I'll go out to my Aries this afternoon and check everything you suggested. I'm not afraid to work on the A/C system, but have very little experience, so I appreciate as much help as I can get.

Later in the day update:

I unplugged the connector on the low pressure switch and use the meter in the audible tone position across the two pins on the switch. I did this with the engine off, with the engine running and finally engine running and the A/C switch pressed in.

Unfortunately, I didn't get a tone, so the the switch is not closed.

Based on this I though...maybe a bad low pressure switch so i tried a used one I pulled out of the junkyard last week. I believe that switch is likely good since the switch bled off for several minutes when I unscrewed it from the donor car. I swapped it onto mt Aries but no tone with that one either.

I think the valve seat valve is seated properly and the switch is depressing it enough. It looks about right... although I guess I could try backing it off a little and see how far it will unscrew before it starts leaking. In fact, when I unscrewed the valve today (from the donor car) the switch had a little hissing when I held it to my ear, so I think its opening the valve. However the hissing was much less then it was when I pulled it from the donor car in the junk yard.

I'm now wondering if there is a leak in the system or if the system is simply too low. I'm not willing to trust my cheap gauge anymore since I think its not working properly enough to get a reasonably accurate reading http://idqusa.com/product/gez-1ezchillr-134acheckgauge

Guess I need to find a better budget friendly gauge and see what the pressure actually is.

[Pete in NH]

Unplug the connector on the low pressure cut off switch. With the ignition key in the run position but with the engine not running, push the A/C on button on the dash. Put a short jumper wire across the low pressure switch cut off switch connector. If the compressor clutch pulls in, you now know all the other wiring is good and it is only the switch that is keeping the compressor off. That switch needs to see somewhere around 30 to 40 pounds of static pressure to close. You have a mix of refrigerants in there now and who knows what the system charge level really is.

An R-12 system has shrader valve ( like a tire valve) service ports. Your R-134 gauge will likely not match up with them and give you a reading. Unless of course you have put R-134 conversion adaptors on them.

[1987dodgearies]

Thanks Pete, I'm headed outside to give that a try right now. If the compressor seems to do something with the engine off, I'll report back...well either way I'll give an update.

Aside of helping me, I'm hoping that documenting this might help others with the same problem in the future,. Its nice when you can follow a general guid what to do next when it comes to testing this A/C stuff.

As far as fittings...... I had purchased a set of R134 adapter fittings to retrofit my R12 system, for charging purposes with cans of Maxi-frig. My cheap R134 type gauge does fit the low side valve, however I think the cheap tool is just not working properly. It used to hold the pressure reading till you pressed the pressure bleed button. The tool no longer really holds a reading and doesn't seal correctly when you press it to the valve on the low pressure fitting.

Later in the day update I just performed the test with the jumper. I tried it with the engine in the on position but not running and the compressor clutch didn't react. I then tried it with the engine running and the clutch didn't do anything.

The thing is I know the compressor will turn on if it gets power and a ground...meaning, a few days ago I did about a 1second test, by jumping the compressor (with the engine off) directly to the battery itself and it kicked in. I didn't want to damage it any more then about a second but that quick test allowed me to verify the clutch still works.

I'm now wondering if the on /off switch is bad on the dash and simply not allowing it to ground, when by pressing the button in. I could pull it from the dash and run a jumper across the wires themselves, bypassing the switch and see if that's the problem (or at least the main problem) assuming I don't have a leak and low pressure in addition to an electrical issue.

I went out to the car and pulled the air/heater control from the dash.
I verified that I have continuity on the blue wire w/red stripe, from where it plugs into the back of the control, to where it runs to the plug of the low pressure switch.
However I just realized, I forgot to test it at the leads (inside the heater control itself) to make sure its making contact with the switch itself...darn

I also pulled the A/C on/off push button out of the heater control and tested it as well. It has continuity when pressed in.

The second wire on the low pressure switch is brown and runs to the A/C relay on the drivers fender well. That wire had continuity from the plug of the low pressure switch to the end that plugs into the A/C relay.

I'm going to have to pull out the heater control again and make sure it has continuity from where the two wires enter to where the A/C on off button attaches. Guess I'll be taking off the dash bezel again tonight.