AC compressor engages for a second and shuts off - blowing hot air

[SLT617]

I noticed a week or two ago that my AC only worked for a minute or so and then would stop. I had a freon charger so I hooked it up to add more but I noticed when I turn on the AC that the compressor turns on for a second and then shuts off. It did this a couple times over the course of 5 minutes. I think when the compressor shuts off like that it's because something else could be bad like the ac pressure switch.

Does anyone know the wires or fuses I should check before taking this over to an A/C shop? Wanted to see if I could diagnose this before heading to a specialist. The Chilton's shows the location of the A/C pressure switch for the 4.7 but I have the hemi.

 

[JPT]

Do you think it is overcharged?

 

[crash68]

Your going to need a set of refrigerant gauges to determine what the issue is. There was another post where someone was saying the person's pressure switch was bad, if I remember correctly it was the compressor clutch.

 

[SLT617]

Do you think it is overcharged?

I don't think so. It worked fine last summer and I never had to charge the A/C. It's just now after the winter that it's not working. I'm guessing it's something else.

 

[Outbreak]

I believe that's a typical sign of not enough freon, of whatever they're using today. I may be wrong though.

 

[14RAM1500BG]

Compressor has to be running for freon to be added. My older truck I had to bypass the low pressure switch to charge the system.

 

[CBTBOB]

Probably a bad compressor clutch, low pressure switch, or a broken wire.

 

[SLT617]

Compressor has to be running for freon to be added. My older truck I had to bypass the low pressure switch to charge the system.

Will I need to force the clutch to turn on in order to put the freon in then? The gauge I had said it was low but after the compressor shuts off the pressure goes high. I'm also going to check the wires to see if any of them look off.

 

[Wahrsuul]

I don't think so - if it's low, it should start taking the charge till there's enough to turn on the compressor. I've added some to the wife's Edge that way. Thing is - if it's low, why?

 

[SLT617]

Well I noticed that the harness to one of the fans in the front

I don't think so - if it's low, it should start taking the charge till there's enough to turn on the compressor. I've added some to the wife's Edge that way. Thing is - if it's low, why?

because the truck is seven years old and sometimes the a/c needs to be recharged?

 

[SLT617]

I noticed today that the fan plug was disconnected. I'm guessing it's to the condenser fan. I put a little more refrigerant in it but the compressor only goes on for a second or two so I can't really get an accurate reading on it. I did notice that it's coming on more often (maybe every 10 seconds) but the compressor is now making a humming noise when it's on now. I'd put more in it but I'm not even sure if it's overcharged. I looked at the fusebox to see if there's an ac relay but couldn't identify it so I can't figure out how to make the compressor manually turn on. Can't find anything in the forum or on google either. I'm at a loss here.

I'm going to take it to a mechanic tomorrow. They do a $20 diagnostic and then charge for freon if it's low. I guess I'll start there.

 

[JPT]

because the truck is seven years old and sometimes the a/c needs to be recharged?

This isn't how it works. It is a closed pressurized system. You shouldn't have to add refrigerant unless there is a leak somewhere.

Some auto manufactures will remove all the old refrigerant and fill with new as maintenance, but still, the system should hold proper pressure.

 

[JPT]

I'm going to take it to a mechanic tomorrow. They do a $20 diagnostic and then charge for freon if it's low. I guess I'll start there.

Make sure they add the UV dye when they recharge the system. You may want to do a quick cleaning of the engine (if it is messy) before this. This way, when it leaks, you/they will have a clear way to see where it is coming from.

 

[SLT617]

Make sure they add the UV dye when they recharge the system. You may want to do a quick cleaning of the engine (if it is messy) before this. This way, when it leaks, you/they will have a clear way to see where it is coming from.

I took it in and it had enough refrigerant. The problem was that the compressor had seized up a little but they got it running again. Makes me wonder if I should get it drained and cleaned out. I'll let it go for now I suppose and see how long it lasts.

 

[Wahrsuul]

Wonder if there was enough oil in the system.

 

[crash68]

Wonder if there was enough oil in the system.

The clutch seizing up has nothing to do with the oil in the AC system. For the oil to be low/leak out, he would have been low or out of refrigerant. The clutching assembly and bearings for it are completely outside of the sealed refrigerant system.

The bigger question is the clutch assembly replaceable without having to replace the entire compressor if it gives him problems again.

 

[RoadRamblerNJ]

Wonder if there was enough oil in the system.

Oil is in the refrigerant. It doesn't lubricate the clutch fan.

 

[RoadRamblerNJ]

Oops, Crash68 beat me to it. Shoulda read one more post lol.

 

[SLT617]

according to Scotty Kilmer, it could be because there's junk in the condenser.
I'm hoping it lasts all summer... and if it does, I'm going to turn my AC on here and there over the winter to make sure it doesn't lock up again.

 

[crash68]

If there is metal coming out of the compressor itself and that's what "locked up", it's not long for this Earth...plan on fixing that soon. Your lucky your truck doesn't have the new 1234yf refrigerant...if it did, be prepared to shell out $$$
The clutch on the other hand can be problematic and some are replaceable separately