repoman

needing to replace the thermister probe swith in the evaporater core on my 2008 dodge 4500 can you tell me where the swith is and do i need to pull the dash or can i just pull the box? my ac is freezing up going down the highway and compressor wont cycle and freezes up, help please cause its hot here in texas

1-2-3

Are you sure it's not just low on freon? That'll freeze it too and is more likely

Elshadow001

Lack of air circulation does the same thing

repoman

unit is fully charged compressor just wont cycle and freezes dealer says there is no low pressure switch it just has probe in evaporator box has anyone ever replace this probe just trying to find out what kinda job i have ahead of me.

GCAT

I believe the entire air box has to come out to gain access to the evaporator.
That means dash R and R. You might think about installing a new evap core while you are their?

1-2-3

If I remember right, isnt this a bulb type sensor, and would there be any chance someone could remove the blower and reach the evap enough to adjust it. Maybe its up again the coil

patdaly

I thought at least on the older 3rd gens, someone had figured out a way to cut an access panel then cover it over? Some might be worried about cutting into an 08, but I sure wouldn't.

Busboy

Make sure that it's draining properly as this would also cause it to freeze up. The only type of thermistor I have seen are inserted into the coils and must go in quite a way or they don't read correctly. I would look on the outside of the plenum for 2 wires going into the evaporator area, they can only lead to the thermistor.

dr7h41

From the service manual:

REMOVAL

1. Disconnect and isolate the negative battery cable.
2. Remove the glove box from the instrument panel (Refer to 23 - Body/Instrument Panel/GLOVE BOX, Instrument Panel - Removal) .
3. Disconnect the HVAC wire harness (1) from the evaporator temperature sensor (2) located on the top of the HVAC housing (3).
4. Remove the evaporator temperature sensor from the HVAC housing by pulling the sensor upward while tipping it forward.

The sensor part # is 68004239AA - $16.85 List

repoman

its a cool day in texas now!!!!!!! thanks for all the info. the probe wasnt the problem the evaporator was really dirty and dodge dont have cab filter to catch all the dirt and dust. had to remove the blower motor and wash it out with water hose most all water went out the drain hole. with the help of some a/c coil cleaner truck is back blowing sonw *****. today is a good day

repoman

your right on the money easy 5min deal thanks for the info