I recently had the computer go down on my ram and had it reprogrammed through B&G. My question is that after i had the truck sitting for a few weeks without running, now the AC is not working.

I had the evaporator and heater core replaced this spring. I noticed while checking the pump that it runs for about one second then shuts off for 10, then repeates the same thing. I checked all the fuses and switched out the relays, but it still only runs for 1 second at a time.

I am pretty sure that the system isnt getting any pressure and thats the problem, but i am wondering if anyone has any ideas on what i should be checking, or is it time for a whole new pump?

thanks

 

Mine does that too, it's more like 2-3 seconds on then 8-10 off, I have looked it up on some other forums and asked the "experts" at o'reilly auto parts and the consesus seems to be the A/C clutch cycling switch. My problem is that it doesn't get that cold and it takes about 30 minutes to get to that not so cold temp.

I'm might head over to the parts store today and pick one up, I will keep you updated on the results if I do decide to go.

 

I am having a/c problems too...after I replaced the compressor, accumulator/drier, and orifice tube the rear end went out in mine and it sat for two months. Now the compressor clutch wont engage at all. If I remove the a/c clutch relay then barely install it and wiggle it, it will come on for a few brief seconds then go back off...and I have already tried swapping relays and it does the same thing...was working like a dream before it sat down...any thoughts?

 

Im having the same problem, not getting any cold air and windows are constantly fogging up. Where exactally is this cycling switch located? Let me know if you find out anything on this that would help me.

Thanks

 

The low pressure switch is on top of the accumulator. You can replace it for about $20 from advance, autozone, etc. There is a schrader valve under it so you don't have to workk about being blast with 150psi of refrigerant. It is a very easy replacement.

The purpose of this switch is to kick the compressor on when the pressure increases. If the switch is bad it will contiune to cycle your compressor on and off.

The first thing you should do is get a set of gauges and see what your pressure is like. You could be low on refrigerant, and it may not be the switch.

You could try a shade tree method of jumpering the connection for the switch which will keep the compressor on and see if your air gets cold. I wouldn't do this for long becuase it will cause your compressor to run non stop. Your compressor will burn out over time because your lines will eventually freeze. Also, if you are low on refrigerant your compressor could burn out from lack of lubrication.

 

On my 98 ram the relay is in the "box"(don't know its proper name) that sits under the hood between the battery and firewall that has all the relays in it and has the relay labeled a/c clutch relay...its just a five prong relay...mine was fully serviced as I put a brand new compressor, accumulator, and orifice tube in it...will look into this switch....

 

Check pressures before spending money on parts that you don't know are bad.

 

I was under the impression that you couldn't check the pressure unless the compressor was actually running / clutch engaged...is that wrong?

 

There has to be a minimum pressure for the compressor to run at all. The low pressure switch on the receiver/dryer IS that switch. Jumping the switch FORCES the compressor to run. If the system is low enough on charge, the low pressure switch prevents the compressor from running, and chewing itself up.

The compressor kicking on for a second or two, and immediately shutting off again, is a symptom of low system pressure. Put a gauge on it, see what it says.

 

Is there a pic or something that shows what to jump? I would like to see if my clutch is still good before I purchase refrigerant.