2nd Gen Non-Engine/Transmission AC went out, what to check first?

[RDelissen]

Hello all,



last week on the way to CA the AC on my truck went out. The usual has been checked, like fuses, relays and such and they don't seem to be the problem.

I couldn't see any freon leakage or anything, so I guess the system is still charged.



What else is there to check without replacing parts at random or is there an 'easy' check to find what's at fault?



Thanks for any info and the search didn't really get me many posts related to AC problems,



greetz Ron

 

[monkeyman]

Check first to see if compressor engages when on high cool, of not try crossing leads on high pressure switch to see if it is not allowing the compressor to engage as it might be bad. Also low pressure switch. If Freon is at right level I find that the high pressure cut off usually is at fault. (of course other things like clutch fault etc) But I listed the easy stuff
Rick

 

[Sageair]

Freon

I would bet that you have a slow leak and are simply down on Freon. Mine bleeds off about every 18 months . We did a dye test and could not see any leakage on the parts we can see. This leads me to believe the leak is in the dashboard which I refuse to tear apart. So I just recharge every year and a half and life is good. Steve.

 

[DImberi]

Sageair -- How many cans of refrigerant do you need to add? I'm having problems with my AC. There was no cool air coming out, so I added a can of refrigerant and now it is cool, but not cold. It took almost a whole can, but there was still a small amount left in the can after letting it charge for about 10 minutes, which leads me to believe it is full. What do you think? -- Doug

 

[RDelissen]

thanks for the info



Since I'm traveling for work right now I haven't had time to dig into it, but I'll check out the suggestions ... because with the temperatures getting into the 90s a working AC unit would be great :-laf

 

[JoeBioDiesel]

If you're going to add your own refrigerant, make ABSOLUTELY SURE you don't add any that says it contains sealer. That stuff wreaks havoc on your AC system and can destroy the refrigerant reclaimers that repair shops use. If a shop detects there is sealer in the system, they won't work on them.

Joe

 

[jmy]

If the compressor clutch is not operating it can be can be the pressure switch, or some other problem, but what I see more often with trucks that have 200K plus miles and heavy AC use is the clutch plate is worn and the gap between the plate and armature is too wide.

You can see whether the clutch is engaged from the top. If it is not engaged the clutch plate on front of the hub will not be turning.
If the clutch is not engaged you can check If the plate gap is causing your problem (with the engine off) by removing the AC relay and jumpering across the normally open contact. If the gap is too wide the clutch usually won't engage with the jumper alone but if you tap the clutch plate lightly it will engage.
The clutch plate is usually shimmed to set the gap. Often you can remove one or two of the shims and the clutch will work again.
The clutch plate is easy to remove from the under the front of the truck. Takes about 5 minutes with a 13mm 3/8 socket and 2 flat blade screwdivers. The plate is on a splined shaft with a skip. It slips right off with a screwdriver blade on each side. You can then remove the shim(s) between the clutch plate and shaft collar. You'll need to line up the skip in the splined shaft to re-install the plate.

 

[JKaps]

My 02 had the same problem took it to the local deealer (that I can trust) and said the evaporater had rotted out. I questioned him and he said it was a fairly common problem. also said alot of dodge cars that it only last about 3 yrs.

 

[billp102740]

Check your Pyro cable . Mine wore a hole in the alum. A/C line and lost my 134 charge . Patched the hole and 5 years later its still good .

 

[Matt42]

Using a refrigerant vacuum, evacuate the entire system for at least 40 minutes once you attain 27 - 29 inches (hg) of vacuum. Close off the service manifold valves and make sure that the vacuum holds for 2 hours. If it passes the above tests, add the exact weight of R-134a that the underhood label calls for. (You will need to jumper--short really--the pressure switch. ) Slightly less R-134a is better than more.

Just adding R-134a may mean you are adding refrigerant to a system that has some air in it. That won't work well, and may produce cool-ish air, but not cold air. Adding too much R-134a will also give you cool-ish air, but not cold ait. The old R-12 systems were much more forgiving for a slight overcharge than are the R-134a systems. The R-134a systems perform well with a very slight undercharge, then as more leaks out, stop altogether.

Doing this job is not terribly difficult, but some tools are needed to do it right.

 

[Matt42]

Using a refrigerant vacuum, evacuate the entire system for at least 40 minutes once you attain 27 - 29 inches (hg) of vacuum. Close off the service manifold valves and make sure that the vacuum holds for 2 hours. If it passes the above tests, add the exact weight of R-134a that the underhood label calls for. (You will need to jumper--short really--the pressure switch. ) Slightly less R-134a is better than more.



Just adding R-134a may mean you are adding refrigerant to a system that has some air in it. That won't work well, and may produce cool-ish air, but not cold air. Adding too much R-134a will also give you cool-ish air, but not cold air. The old R-12 systems were much more forgiving for a slight overcharge than are the R-134a systems. The R-134a systems perform well with a very slight undercharge, then as more leaks out, stop altogether.



Doing this job is not terribly difficult, but some tools are needed to do it right.

I thunk I clicked edit, but I clicked quote. Silly me.

 

[djosip]

I have had this type of problem over the past 2and 1/2 years. Initially I had a leak(dye) test done but nothing showed so I had the sys. recharged and it lasted for about 10 months. Again I had a leak test done(no joy) and recharge. The next time after reading threads on TDR, I concluded that the seals in the system were drying out(hardening) and decided to use a sealent which said it was mainly for seal re-juvenation. I usually add 1 can of r134 after adding the small can of sealent. This lasts anywhere from 9months to 1yr before it needs to re-done. Using Walmart products it costs me about $12 each time. I prefer to do this versus gettting a pro-re-charge at $80 a wack. there appear to be no adverse effects using the sealent.

2001. 5 HO, 6sp. longbed. 105kmiles