Just wondering did the previous owner say anything about having the body on the front end worked on? Ie a front end collision? I few years back I hit a slick spot on a road and ran my truck into a power pole. I thak god I have full coverage so i took it to a body shop that we've used for years. They had the truck for two weeks doing all of the repairs this was in Feb at the time. so when summer hit and i started to run my ac it worked for about a month then it quit. after fooling around adding coolent ec. i used an engine stheoscope and found that the clutch in the compressor was shot. Idk if your compressor is running non stop or not, but that might be your trouble. I went back to the body shop and talked to the owner,long story short when they dimantled the front end the idiot that was doing it just unhooked the line instead of bleading it off. i assume that when he did this it blew all of the oil out of the compressor and they didnt add any more to it when they recharged it.

 

It's never been wrecked that I can tell. The paint match's good and the fastners to the rad supports, fenders, hood, ect. have never been removed. At 160k I think it just lacked attention. I may just have to bite the bullet and take it a shop, but not till iv'e exhausted every option.

 

I had a similar problem. My truck has never been wrecked or anything and is still in great shape for a '98. It started out as the A/C would go in and out. No real pattern to it. The dealership couldn't figure it out after quite a few visits in 3 years so they just said it was in the dash and it would cost a grand to fix. So we decided the A/C wasn't worth that much.

A few months a go I had a mechanic where I work check it out to see what he could find. In 10 min he told me the clutch coil was shorted out. So I ordered the part from www.moparpartsamerica.com and changed them out myself. It wasn't that hard. I put in a can of freon and It's still working great. 39 deg air last time I checked

When it worked on and off It must have been the coil faltering. A few years later it finally broke and that's how my friend found it.

Hope this helps.

 

I bought one of those cans with the gauge on it and it showed no pressure. I followed the directions on the can and got it up to where it said it should be and the compressor began to cycle. But it still blows warm air and the hoses are still warm and not sweating. Cold weather is only a month away and the heater works so I guess I know where my tax return is going next year.

 

Evap core is shot for sure on a 99.

 

Mine did the same thing when I tried that once. The cans with the little single hoses don't work too well. They only hook up to the low pressure side.

There are a couple wires coming from the clutch coil there is a connection not far from it. Disconnect it and test the resistance on the coil. If it's broken then that's a cheaper fix than much anything else to do with the A/C.

 

I'm probably going to have a shop put a set of gauges on it to pressure check both the high and low sides and put actual charge in it. At least eliminate that aspect. Zman, when you say evap core you mean under the dash correct? Not the canister. And simpsonna are you referring to the low pressure switch. Thanks to all for all the help and input.

 

Yeah having a shop put the right pressure in the system will help. But If it still doesn't work I was referring to checking the clutch coil.

The pulley the belt runs for the A/C compressor has a clutch that turns it on and off. If it is cycling on and off it usually means it's low on freon. But if it has freon in it and it still won't turn on then the coil could be shorted out. (Or it could be a lot of other things I'm sure) The coil contracts when it has voltage in it and makes the clutch catch the pulley, when it does it will make a click and the center will spin with the belt.

Right there about 3-4 inches from the pulley on the compressor is a (black) disconnect. Those are the wires for the clutch. When you take it to get freon in it have the mechanic check the resistance in the wires to see if the coil is shorted out. (he should do this if the system doesn't work when filled)

That was my problem. I think it was an $80 part and I didn't have to mess with the compressor. Hope that helps.

 

I'm gonna take it to the dealer here shortly. They said they can vac. , charge, and give me a diag. for 55$. Really reasonable I think, eliminate a bunch of guess work. Thanks again for all the help.

 

Yep, without the proper diagnostic tools it is pretty much guess work.