Hello, I am new in the forum , I am from Argentina.
I need your experience in the RAM 2500 diesel. the issue is with the a/c system.
The compressor clutch is alwyas on, I chequed the pin in the TIPM and itis 12 v, but I checked deeper and the power IC thats drives the clutch signal looks ok. Is a power mosfet. I make test over it and looks fine. The more strange situation is that I got 12 v in the pin #3 of the the TIPM even with the start key off.
I can not found whre the fail come. Any help is welcome.thanks Gus.

 

The 12v at all times at the Pin is probably normal. It wouldn't transfer that power until the key is turned on, which still mean there is 12v at that pin.
Your in Argentina, and i suspect it's warm there. An A/C clutch that remains engaged says that either your defroster action is on(top vent) and that your system is working properly. I bet your clutch does cycle while you are driving down the road and at higher rpm's than at idle.
A/C does more than just provide cold air, it removes condensation to prevent freeze, it also aids in defrosting the windshield and removing moisture in the system.

I'd say at this point you dont have any problems. A/C clutches that cycle frequent are generally low on refrigerant or are not needed(mild weather)

 

Hello Rich, thanks for your answer. May be for my poor English write I need to explain better , the key that I talk about is the one to start the truck, to start the engine. Even with this key out of the track, that's means that no should work any accessory in the truck, the TIPM send a 12 v to the clutch. That is the more strange, and don't looks like the power IC that drive the 12 is burned. I am a electronic engineer, but the in this case the monster give me a lesson. :-)
I am afraid to do more test over the TIPM, because as I read in the forum this box handle all, if I burn something else may be will have a big problem. what do you think???.
Thanks and best regards.
Gus.

 

Sometimes we have constant 12v on some of our things but the ground needed to complete the circuit isnt given until a button or switch is pushed.

I have to ask, what is your AC doing or not doing that is the problem.

 

Download the service manual in Weedahoe's signature. 2006-2008's are the same for specs. It will tell you what the voltage needs to be when measured at the compresor end and where exactly to test as it's not a conventional style system.

 

Yeah, these things use switched grounds. Drove me crazy installing my radar detector in my Chrysler.

 

Hello people, thanks a lot for your answers. Yes, I download the manual and check it very carefully, the clutch is handle by the TIPM and the other pin of the clutch goes to the ground distribution point. Up to now, the problem is the same, the clutch is always engaged even with the ignition key in off position. I turned around the TIPM control signal, connector C9, even when I disconnect the C9, the clutch still engaged.
I read some advice about reset or flash the TIPM , I test to disconnect the batteries for a hour, same thing after reconnect. Any advice ?? , I will continue making test and working around, but really don't have a north to follow. Thanks for your helps.Gus.

 

The only way to reset the tipm is to have an authorized dealer with a Starscan tool do it for you. It's a special program within the handheld unit.
Diconnecting the battery and touching the Pos-Neg terminals together only depletes the capacitors within the pcm unit that stores active information as the pcm is voltile. Or, leave the battery unhooked for 1hr as you did will also deplete the internal capacitors. The tipm contains both active and stored info until deleted by dealer and is classified as non-volatile. This allows the dealer to find out information if the battery has died or has been removed. I'm sure you know all about that sort of stuff....