2000 Durango / 4wd / 5.9L / 165,000 miles

A/C comperssor was replaced last summer, they did the complete purge/evacuation/re-charge deal as well, but didn't replace the pressure switches (low or high). This year I've noticed that sometimes during the afternoon drive home, the air will blow warm for a minute or two, then get cold again. This cycle will happen for the rest of the evening. This cycle only seems to happen when it's hot in the afternoon.

The system seems to have enough 134a. Cooling system is new as well and functioning properly, both radiator fans appear good too. Console switches seem to operate correctly (all fan speeds good).

I want to replace the low- and high-pressure switches, but can I do this without losing the system charge, or is a purge/re-charge necessary?

Any other suggestions welcome.

 

The PMC shuts down the a/c ifthe truckis too hot. (over 210)

 

cooling system is fine (recently re-done). No leaks, fluid good, operating temp is normal - doesn't get to 210.

 

i took a little piece of wireand put2 flat connectors on each end. unplugged the wire connector on my low pressure switch, and jumped theconnection with the wire i made. been on there for a year now works great!itwouldnt work at all before i did this.
do not jump the high pressure switch!!! i tried that and results were bad thought i blew up my compresser.

 

here are some pics

 

here i fixed it for ya

 

thanks man, im better at working on vehicles than websites

 

I realize this an old thread... but this was my problem exact problem. Condenser fan wasn't kicking on, but when I jumped the low pressure switch connection, the fan kicked on. I checked the relay first, motor and was stumped.. then found this thread. So thanks!

By the way, the pics no longer work.

 

So the compressor is still running, but the fan shuts off? Seems odd, but ok. The pressure switches can be replaced easily, they have schrader valves under them so you won't loose all the refrigerant.

 

Can't speak for the OP but in my case the fan would never kick on... even though the compressor would kick on when turning on the AC. I'm not sure on this: but I think I read that if the condenser fan doesn't run when the compressor does start, eventually the (evaporator coil?) will freeze causing the compressor to stop, and warm air to come out of the vents.

Nice to know I can change that switch without losing my refrigerant, but in the meantime the jumper wire is working. Thanks