Hey guys,

New to the forum & new to Dodge Trucks.

I just picked up a 2001 Quad Cab 4X4 with a 5.9. The rig has 48k miles and is in great shape. Got it off of ebay for 11,350.

One small thing that is really bothering me is that the AC compressor is constantly cycling on and off; it never stops. The AC does not blow very cold, so maybe it needs a recharge, but the compressor cycling is starting to drive me nuts.

Is this common? Does anyone have any idea why it might be doing that?

Thanks for the help!

Doug

 

on my 2000 it would cycle on/off with the defroster... the 2005 acts like yours... cycles on/off all the time. I think whenever the fan is on it may be conditioning the air slightly.

 

I heard or read somewhere that the compressor cycles on and off to keep the compressor and the seals oiled.

 

The compressor doesn't cycle unless a/c is requested...or the relay or wiring is bad.

If it's cycling every 10-15 seconds or so, that's about average...if it's cycling every 2 or 4 seconds, it's low on refrigerant and can't maintain the proper pressure since it's low, and it sounds that way since it's not blowing too cold. Have it checked out, should be $30-$50USD for someone to check it.

 

The compessor will cycle on defrost also to dry/condition the air to aid in the defrosting cycle. As he said if it cycles continuously, either add some freon or get it checked and find the leak. Mine has needed freon in the spring for the last two years. Freon level gets low. Need to find the leak. It's on the to do list.

 

unless ive been doing it wrong for the last two years (30+ cars including my own) it should cycle on an average of once per 50 seconds if you have access to some gauges it should turn on at approx 45 psi then shut off at approx. 10-15 psi, but i would bet it is low on 134a at least by 6-8 oz. if your compressor was shot it would either run forever or not at all hope this answers your question

 

Yes your correct...[sm=oopssign.gif] I missed the cycling for 2-3 seconds part.[sm=bangbang.gif]