joeinblueout4u

The other day while driving to Ft. Worth, the A/C almost completely stopped coming out of the vents. There was a slight stream of cold air, but no real flow. The mode switch would not change the air flow from Max to any other mode, even defrost. The fan was turning at High and maxing a lot of air movement noise in the evap box, but little came out. We had been on the road about 2 hours when this happened.

We stopped for a few minutes and shut the truck off. When we restarted the truck, everything was back to normal. On the return trip, after about another hour and a half of highway driving. The same thing happened just outside Ardmore. We stopped to grab a bit and shut the truck off. Again, it began working normally and did so for the next hour to home.

I'm guessing this may be electronic.

What say the knowledge here?

-Joe

cdennyb

Is there a chance there was a freeze up of the core?

jhenson

When you have no air movement out of the vents with the a/c on then your system is low on 134 and the evap core froze. Like you stated.....you shut it off and let it sit and then all was good.....until it happened again. The core basically turns into a solid chunk of ice that air flow cannot pass through.

You witnessed the classic symptoms of a low charge my friend.

joeinblueout4u

Excellent. You saved me from a real headache. We bought this truck a year ago through a dealership and one of the conditions of sale was to repair the non-functioning AC, which they did. It was working great until the other day, so there is a small leak to contend with but, a proper charge should help for now.

I guess this would also explain the condensation I observed on the bottom of the evaporator box when I looked at it the first time.

-Joe

ddestruel

theres a lengthy thread here on the AC systems on these trucks. my 2003 has a full charge but will still freeze the core like you described.

couple other culprits that have been thrown out on that thread
supposedly there is a pressure side line with too small of an orifice causing it to "flash" that can be updated to the, as well the temp switch in the core on some of the early trucks is not located correctly and dodge has a tsb for moving it to a different location inside the core to prevent freeze up........

230k miles im still procrastinating on this. all i do is turn off the ac for a few minutes while letting air continue to blow then turn it back on once full flow resumes