jeepme79

There's something up with my A/C. When sitting at idle, it works fine, but when I get moving down the road, it is worthless. It had enough freon, but was on the low end of good, so I recharged it with an auto store can this weekend, but that didn't help. Is there some kind of sensor or safety switch that could be killing it when I am driving?

rdefayette

Have the A/C temp sensor checked.
I have an '03, A/C would work, then freeze up and NO air would come out of the vents. Would turn off the A/C for a couple of minutes, turn it back on and get water vapor and a LITTLE air out of the vents.

Had Dodge check it, turned out to be the A/C temp. sensor (best as I recall, would have to check the work order). Bad news, to replace, MOST of the dash has to be removed, if this is done, save yourself some trouble down the road and replace the evaporator now while everything is out and the A/C is discharged.

Hope this helps.
Bob

Jason Foster

I had a similar problem a couple of days ago. I went to Walmart, idled in the parking lot, picked up some plants for landscaping and then went home. AC quit on the way there. Compressor stopped, AC light went off, vents blew hot air and the light for the sideview mirror heater started flashing. Parked the truck for a couple of hours and when I started it, the AC came on. Haven't had a problem with it since. I'm thinking that I'll have something to replace sometime soon.

Spooler

Your A/C evap. froze up. The fin temp sensor cut it off due to the problem. Use the search function for the old thread about it. It is liked in the above thread.

https://www.dieseltruckresource.com/...t=pass+side%21

jeepme79

Well, after testing a few different scenarios, here's what I have...

1) When I first start the truck and take off, I get cold A/C for about 5 minutes, then it is as if I shut the A/C off and am running just vent
2) When it is working, it works in both fresh-air and recirc mode.
3) When it is cold, it is cold on both L and R sides, so that doesn't seem to be the problem.
4) After the A/C dies, if I shut it (air) off for 5-10 minutes while going down the road, then turn it back on, it will work for a few minutes, then stop.

The A/C works, but something is causing it to shut itself off. I don't know if it is a sensor, preasure, freezing, or anything else. I ran a parts store recharge can with a guage. It was a little low, but not enough to make a difference so freon shouldn't be an issue.



A little update for tonight, I checked the codes tonight and saw a "P0647 A/C Clutch Relay Ctrl Circ Hi"

Could it be that at the higher rpm's the A/C clutch is still grabbing hard and turning too fast?

Spooler

Check the wires going up to the High/low pressure sensor. They have a tendancy to rub against the A/C lines and chaff. Just something to check.

jeepme79

Where is the hi/low preasure sensor at?

Spooler

On the high side line above the compressor. Can't miss it.