sevobuck

Fin temp is reading 30 when the fan speed is on it's lowest setting; otherwise, if the fan speed is any higher the evaporator freezes up and it reads 70. They are paying for the labor

SpeedyWS6

They need to do a voltage range test, or test the resistance of the fin temp sensor to verify it has the correct resistance for the temp. But they either need to let the truck sit overnight or remove the sensor to do the test. Removal is the only way to know for sure what temps the sensor is being subjected to.

I will see if I can find the resistance info for that sensor.

Spooler

No need to do all of this. This truck is low on R134a. PERIOD!!!!!!!

maxwellp

LOW on charge was my thought from the start and still is. I would need to see a Low side at 35 ish High side 200 ish and it still frozen up like that before I took it apart.
I would Vac it out, refill - using a scale - not a fancy filler that you really do not know what it is doing. Then see what you get.
I would hate to be in your shoes, I wish I could reach in to the computer and help..........
Also the Low PSI switch should have shut the compessor down by 15 psi.

SpeedyWS6

Yeah, I looked for the test and there isn't one anyway.

sevobuck

So there is no way that it could be freezing like that and have the appropriate amount of R134a? Also, where is the low psi switch located (control module, Compressor, etc)? Yes, this is the most frustrating issue I've ever experienced with a vehicle.....just an absolute frickin' mess...

pull-do

Without reading all what's been done, and then looking at the pics of the "freeze" line,, it sure looks like there's a restriction in the line before the orifice tube,, there fore a pressure drop, (same thing as the oriffice tube job) which causes the freeze up before it hits the evap system.

Just a idea to look at if it hasn't already,,,,,

A good shop/AC man should be able to fix that pretty easily no matter what is wrong.

BC847

That would cause the evaporator to starve and not allow enough refrigerant to properly fill the evaporator, much less flood back to the accumulator and compressor suction line.

sevobuck

Is there a low pressure shut-off switch on these trucks?

maxwellp

I have an 05 - I am going to open the hood at look to see if it does.
Mine a/c will freezzzzz you out of the cab even if it is 90 out.

pull-do

Hmmmmm,,, yeah, I realize it would starve downstream,, still thought it would freeze up also, guess not,,, just an idea

Guess that's why I weld for a living..

sevobuck

Thanks for looking....wish I could brag about driving in a meat locker

maxwellp

I do not yet have the Dodge Service Books on these newer ones yet. Some one else must. But I looked at my 05 and there is not a Low PSI switch that I can find. My 96 has one (looked) guessing that my 01 does too, It's not here but I will look.

Dodge must be using the Fin Temp Probe to control the compressor at low demand. The service book could tell us. I have been lucky and just dirve the 05.

I still go with my first thoughts, low on juice or something stuck in line that does not belong there.
Even if that Fin Temp Probe was not working right, at start up you should be able to put in it High A/C (needs to be hot outside) and keep it from freezing up. There would be a large load to keep the compressor running.
Will it Blow out cold if you do this?

sevobuck

Yes, at start up she blows nice and cold but then after about 10-15 minutes you can tell something isn't right. The air starts getting warmer, approximately 73 degrees and then stays like that.
Today I made the 30 mile trek to my dealer and left it on the lowest fan speed with the recirc on and by the time I made it to dealership, the whole thing was totally ice covered. There goes their theory that it doesn't freeze on the low setting....

To top it all off, when they ordered a new sensor, someone in D/C parts put the wrong one in the bag geesh

maxwellp

I am going to run my 05 and see if the compressor shuts off with it on high, I am thinking it will not.