ado2b1

For imbodie (Tim)

Just happened to be glancing over this thread again. Here's the basic way to test your a/c system with the gauge set. Your low side pressure is set by volume of refrigerant and ambient temperature (nothing with compressor). If I can remember to bring my gauge set in tomorrow I'll throw the chart up here. First thing is to fill low side to the corrected pressure. Then check the corresponding high-side gauge and see where your at. The chart has the approx. high side pressures as well.

If your clutch isn't engaging, you can manually override it to get your compressor to spin. It should bring your high side up to nominal and blow cold air. If clutch is not engaging, you have a bad switch or sensor - I have not had to diagnose this though.

If your clutch is engaged, and the compressor spinning but not at the pressure its supposed to be, re-check your low pressure volume. If low press. checks out with still no cold air, the compressor is likely shot.

Partial Compressor Failure:

When the high-side engages, the needle should stay at a steady state. If it is fluctuating then the reed valves on the compressor are going out. Some compressors can be fixed by putting new reed valves in, some are probably not serviceable.

The gauges on the cans are not exactly high quality. I tried to use one without my kit and it also pegged the needle, all the way into its "danger zone", ooh scary. After I got the car (my Dad's old Lincoln) back to my shop I grabbed my set, hooked it up and it indeed read low charge. Took two additional (small) cans to fill the system. It works fine now.

imbodie

WOW...
I knew the gauge sets that came with the 134a from wallyworld were not the greatest, but I didn't realize a full set of gauges was THAT important.

I put one 12oz can in mine a couple of weeks ago because it wasn't dropping to 40 degrees like it did last year. It still isn't dropping to 40, but I didn't want to risk over filling it either. It didn't show overcharged after the first can, in fact it didn't move the cheap gauges. But I figured let it run for awhile and check it again.

-Tim

ado2b1

I guess my memory works as well as I remember. Went home for lunch. Here's the chart that came with my gauge set, along with the troubleshooting/diagnosing tips, some that I kind of went over before.

Also, if you have an "old" gauge set (for R-12), I think you said you were going to dig one up. They DO make an adapter from R-12 to R-134a, though they don't sell them individually at AutoZone or OReilly's. You might give MasterCool a ring (973-252-9119) to see if they sell them individually (or just tell them you lost your adapters for part #89660 in case there is some "legal" issue with selling the adapters).

imbodie

No, I was going to dig out my AC book.... Wish I had a full gauge set.
-Tim

Jmac

Took it to my closest dealer today and the compressor is bad the clutch is bad and the "air box" under the dash is broken. $1279 later it should be fixed, I've got to go ahead and fix it b/c the truck and trailer are headed to WV to haul/sell produce Friday. I appreciate everyone's imput on this. What really stinks is the warranty is for 12 months or 12k miles. WV is 750 miles one way from where we are. That 12k miles will be gone quick!!
Jamie

ado2b1

Ouch. That's painful. Too bad you don't have the time to switch that stuff out yourself. Hope it works well on your trip. I do quite a bit of driving with the 2/55 A/C going in an old ford tandem axle dump. Its so loud you have to put ear plugs in and just kind of hope to hear the radio once in a blue moon.

J BODY

If the compressor clutch draws too much current the "DRIVER" in the TIPM is shut down as to not damage the wiring or any part of the circuit and a dtc is set. Even if you replaced the clutch on your own the code would have to be cleared to verify the repair with the TIPM. Starter is the same way......

...as I said earlier, prob with the "driver", not the nut behind the wheel

Busboy

If it's not too late..... First with the engine NOT running try to turn the front of the compressor, not the part that the belt rides on. If it DOES turn then start the truck and turn the AC on full cold (not MAX), does the compressor engage? IF no, remove the plug from the low pressure switch on the drier, (the cylindrical black thing close to the fire wall on the pax side. Short across the two terminals, does the compressor engage? If NO and you do not have any gauges, remove the connector from the high pressure switch and short across the two terminals. does the compressor engage.Warning do not run the compressor engaged with no gauges and no high pressure protection for any length of time, it's just to see if it will engage.
If still no then supply 12volts directly from the battery to the compressor the clutch should engage without the engine running. If it doesn't engage then the clutch IS bad. If it does engage then listen to what Jbody says and start looking for a wire that has rubbed through in the engine compartment. Go from here and see where you stand

Jmac

too late trucks fixed by dealer and will on the way to WV in early AM.
thanks though.
Jamie