2006 ram no a/c

[dodgediesel91]

I have a 2006 dodg ram 2500 5.9 diesel my ac worked until last year i sucked the system out put new drier on and recharged still didnt work compressor is not engaging the presure is right and the pressure switch is good i put my snap on tool on it and it keeps loosing communication with the ac system i tried new switches in the dash but can not get power down to the compressor only code in ac system is for the temp sensor in heater box so it dont freeze up tried jumping senor and does not show no difference on my scan tool my buddys truck when unplug that sensor says open and if u jump it says 100 degrees mine shows no difference no matter what you do to it i did some reading some say pcm but when i look up pcm i get pcm/ecm/ecu is all one and i dont want to spend that much money and not know the problem if anyone has and input i would appreciate it. Thanks

 

[Bob4x4]

Most common failure is the ac clutch coil. with a good scanner you can access the tipm and actuate the output to the compressor and check for power at the coil.

 

[Grey Wolf]

Bob it probably doesn't get said enough but thanks for keeping as all informed

 

[PWong]

I have a 2006 dodg ram 2500 5.9 diesel my ac worked until last year i sucked the system out put new drier on and recharged still didnt work compressor is not engaging the presure is right and the pressure switch is good i put my snap on tool on it and it keeps loosing communication with the ac system i tried new switches in the dash but can not get power down to the compressor only code in ac system is for the temp sensor in heater box so it dont freeze up tried jumping senor and does not show no difference on my scan tool my buddys truck when unplug that sensor says open and if u jump it says 100 degrees mine shows no difference no matter what you do to it i did some reading some say pcm but when i look up pcm i get pcm/ecm/ecu is all one and i dont want to spend that much money and not know the problem if anyone has and input i would appreciate it. Thanks

DIY guy looking for some fun in troubleshooting???

 

[dodgediesel91]

where is the ac clutch coil ? i can turn the compressor on with my scan tool and it kicks in and blows cold air. also when im in the hvac system with scan tool it keeps saying it looses communication then has to reload and only does it in the hvac system we tried it on my buddys truck and it stays connected. this is why i was thinking it was a module

 

[PWong]

where is the ac clutch coil ? i can turn the compressor on with my scan tool and it kicks in and blows cold air. also when im in the hvac system with scan tool it keeps saying it looses communication then has to reload and only does it in the hvac system we tried it on my buddys truck and it stays connected. this is why i was thinking it was a module

Are you referring to the clutch coil on the compressor?

Since you can use your scan tool to turn on the compressor then the ECM has no problem to turn ON/OFF the compressor.
The ECM,TIPM and the clutch all were good.
The issue was that there was no request/command to ECM to run the compressor.
The ECM gets the request message from the CAN B BUS.
The A/C Heater Control head broadcast the request on the CAN B BUS if the conditions to run the compressor are satisfied.
The conditions would be:
A/C lite ON after pushing the A/C button,
Blower running,
Evaporator temp senser signal read by control head,
Refrigerant pressure message on CAN B BUS, received by control head.

If all the above conditions were satisfied then,
I would try a known good control head.

 

[PWong]

http://www.rambodybuilder.com/2006/docs/wd/dr/wiringdiagrams/8w42airconditioning.pdf

 

[dodgediesel91]

the only thing is it says evap temp sensor is at 1 degree when unplug that does not change when u jump across the plug it dont change got my buddys truck same year unplug it says open jump it it goes to 100 degrees and when plugged in reads about the temp it is in truck and when you say control head you mean the pannel with knobs and ac button and also can the can b bus go bad ?

 

[PWong]

the only thing is it says evap temp sensor is at 1 degree when unplug that does not change when u jump across the plug it dont change got my buddys truck same year unplug it says open jump it it goes to 100 degrees and when plugged in reads about the temp it is in truck and when you say control head you mean the pannel with knobs and ac button and also can the can b bus go bad ?

Yes the panel with knobs and buttons.
It couldn't tell when you unplug the sensor or jump the sensor.
If the CAN BUS goes bad you would some other issues other then the A/C.
Also there would be DTC for CAN BUS issue.

 

[dodgediesel91]

ok thanks i will try that this week and see i tried my buddys but his truck has little different options and control head was a little different i didnt work the plugs where the same but ac still didnt work and i was wondering if it was because his switch was different or because that wasnt my probem

 

[dodgediesel91]

i tried my buddys but his truck has little different options and control head was a little different i didnt work the plugs where the same but ac still didnt work and i was wondering if it was because his switch was different or because that wasnt my probem

 

[dodgediesel91]

tried a good head control still not turning the pump out any other suggestions?

 

[PWong]

tried a good head control still not turning the pump out any other suggestions?

Still no A/C Clutch Control signal from ECM to TIPM???
I would try a known good ECM if sure the wirings were good.