A/C problem on a 01, 2500 diesel.

[srwa]

Comp. running, fully charged, fan on high, engine idling, temp. between 48 & 50 degrees, outside temp. round 92 degrees.

Problem: At highway speed, 65 to 70, temp. starts to creep up to around 70 to 80 degrees.When I get below 35mph temp. starts coming down to 48 to 50 degrees.

All started when I had the upper & lower left ball joints replaced......go figure.


TIA


SRWA

 

[Bigtman07]

Welcome to the forum!!

Interesting question you got there. I have only heard of this one other time and that was on my buddies sable. Still haven't figured it out. I'm not an AC expert but my guess would be that there is a leak in the system or that at highway speeds the heat is too much for the condensor. Just a guess. Other guys will be along at some point to add their input.

 

[mikeish]

Could be that the clutch on your A/C pump is running non-stop.. when your driving on the highway for a long period of time and the clutch continually runs the pump due to a switch error or clutch error your evaporator box will freeze up. The ice that builds up and restricts air flow and you will blow hot air or no air at all. I use to have a similar issue on a old escort i had. If this is the issue then by pass the A/C relay with a switch. If the box starts to freeze then flip the A/C clutch switch to off and let the hot air flow through the evaporator box to melt any ice build up. Then once you feel cool air to war air start to flow throw kick the switch to the on position.