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+--- Thread: Ac Compressor Power Plug (/showthread.php?tid=9035)
Ac Compressor Power Plug - BC77 - 08-07-2023
Hello all. 2009 international prostar with Cummins isx. Been having issues with ac every summer for the last few years. I replaced everything new and flushed out all the lines. I'm not getting any power 12v to the plug that plugs into the ac compressor. My 2 thermresistors are reading 2100 ohms and when I apply 12v from my power probe everything works fine. Any ideas and does anyone know if this controls the plug, see pic? Thanks [attachment=9038]
RE: Ac Compressor Power Plug - Bengy88 - 08-07-2023
Have you connected dlb or jpro to the truck to see if there is any faults? Those systems will kill all power with the slightest issue. Even blend doors actuator failures will cause it. Actually been fighting one of these systems today.
RE: Ac Compressor Power Plug - BC77 - 08-08-2023
No I was planning on following the 2 wires from the ac plug back to see if there's a issue with the wires before taking it to put on the computer for diagnostic. I was curious about that coolant level module pictured because I get continuity between it and 1 wire from the ac plug but not the other wire. I also get continuity from both wires from the coolant sensor on the reservoir to that coolant level module
RE: Ac Compressor Power Plug - Rawze - 08-08-2023
looks to me like your barking up the wrong tree??.
(Prostars and their problematic 'Chrysler-designed' AC system) ...
There are lots of reasons that the cab controller will fire off the AC compressor for about 10 minutes after starting up the vehicle, .. then fault it out.. never to turn it on again until you cycle the key switch. When it does this, many people think it is not working at all... so find out for sure if it is doing this (A/C on max when starting the vehicle up, and jumping out to see if the compressor clutch has kicked in) .. or not coming on whatsoever.
Are you sure that it is not kicking in for about 10 minutes and then faulting out?... or will it no fire the clutch on at all whatsoever after a key cycle?.
There are typically only a couple reasons the cab controller will refuse to engage the AC clutch at all whatsoever.
#1 reason = The cab controller does not see above 50-psi.. and below 350psi pressure (bad high pressure sensor or wiring going to it).
#2 reason = one or both thermistors are reading dead short (only a few hundred ohms or less) .. or really high (above 10,000 ohms i think).
#3.. the cab controller is reading the key switch position in the dash incorrectly. Yes this does happen due to tarnished fuses in the fuse panel, yet the fuses are all good. It is common on prostars where fuses are good but have some resistance, leading to incorrect logic. Here is some related info on this: https://rawze.com/forums/showthread.php?tid=1514&pid=12861#pid12861
-== Otherwise.. the system will kick on for 10 minutes after key on, then fault out if there are issues ... never to kick back on until keyswitch has been cycled. -= This is 99% always bad thermistors, but can also be bad humidity sensor, bad Ambient temp sensor readings too.
Some delete programs running around out there for the engine will disable the ambient temp sensor.. some trucks do not like this... some don't care about it. disabling it can effect the AC system on some model prostars.
== bad blend doors will not cause AC clutch itself to not work... though you might not get any cold air, as those plastic doors typically get stuck half way open or on the hot side, or some other garbage position, not allowing the cold air to pass thru into the cab... but the compressor part of the system will operate (at least for a while at a time) if it sees proper pressures and thermistor feedback.
read these posts ...
http://rawze.com/forums/showthread.php?tid=3348&pid=28913#pid28913
and...
http://rawze.com/forums/showthread.php?tid=8277&pid=72161#pid72161
and...
http://rawze.com/forums/showthread.php?tid=4734&pid=40694#pid40694
and if you just cannot solve it whatsoever.. YOU NEED THE CAB CONTROLLER SOFTWARE to see why it will not kick on... or to see if it IS trying to kick on and the internal circuit may be burned out. - For all anyone knows, the cab controller might be thinking the engine is cranking all the time or some other stupid s$it, like mine did once a long time ago... never to throw a fault for it.