99 Ram 1500, 5.2, auto. I had a problem with my air ducts where the blower would switch from panel to defrost on acceleration found posts and bought a check valve that fixed that problem. I recently started running my ac and it will not stay cold. It will blow cold for a while and then blow less cold and then not cold progressively. If I shut the whole system off or stop the truck for between 2 to 5 minutes it will come back on cold. Is this related to the vacuum problem. Is there a door or something in there that diverts the cold air because it won't stay open? Any help appreciated.

 

could possibly be a leak on the cab side of the heater/ac system... here's another thing to check... fire it up, let it blow cold, then when it starts to warm up, take a peak at your compressor and see if it's cycling on/off like it should. it could be that you are low on freon

welcome to df.

 

Yeah, do the above, and if the compressor stops when the air blows warm, tap on the clutch face (carefully, the engine is running) if the clutch grabs and cooling starts again, you have a clutch gap problem. If that doesn't get it going try jumping the low pres. switch and see if that gets the compressor going. If so, probably low on charge. Get back and let me know results. Do you have a Gauge set?
WC

 

Thanks guys. Its the clutch gap problem. Guess I'll do a search to figure out whats next. Appreciate your help and suggestions.

 

New compressor? One shop told me they might be able to adjust the clutch gap by removing shims. Has anyone done this? How tough a job is it? Thanks.

 

Clutch gap adj. requires specialized tool. Not worth it for the DIYer. If you have an auto parts place that lends tools you could inquire. The gap should be .012 or about the thickness of a business card. OR: Take it to an A/C shop. Shouldn't cost but a nominal fee; not even an hr. labor. If more, find another shop.
WC

 

Thanks Wayne really appreciate your help...