AC Compressor Won't Shut Off

[ASchwartz]

When I turn the key to accessory on my 03 the ac compressor clicks on and won't shut off. It started turning itself on and off intermittently, but now does it all the time. Any ideas on what the problem could be? I recently had the ac charged and that did not seem to fix the problem.



Avi

 

[cerberusiam]

Check the wire that runs from the compressor to the harness. It will sometimes rub on exposed parts and create a condition that the ECU thinks it should activate it.

 

[SShafranko]

Mine was doing the same thing at one point but i also had other issues as well. I did two things at the time. I hat my Tipm reset at the dealer and i also installed a new computer. I dont know which one fixed it but it hasnt done it since.

 

[ASchwartz]

Check the wire that runs from the compressor to the harness. It will sometimes rub on exposed parts and create a condition that the ECU thinks it should activate it.

I will check that wire and let you know what I find out?



Thanks

 

[ASchwartz]

Mine was doing the same thing at one point but i also had other issues as well. I did two things at the time. I hat my Tipm reset at the dealer and i also installed a new computer. I dont know which one fixed it but it hasnt done it since.

What is a Tipm and which computer? That sounds expensive.

 

[cerberusiam]

What is a Tipm and which computer? That sounds expensive.

TIPM - totally integrated power module. AKA, really expensive fuse box.



You don't have a TIPM but it could be the front control module as that is what powers everything at the direction of the ECU (computer).



The other thing on your 03 is it had problems with corrosion on the ECU connectors that causes all manner of electrical glitches. TSB for cleaning and resealing them at dealer.

 

[JJPage]

The other thing on your 03 is it had problems with corrosion on the ECU connectors that causes all manner of electrical glitches. TSB for cleaning and resealing them at dealer.

Hey Cerb, is the ECU the connection block on the passenger side firewall?

 

[cerberusiam]

Hey Cerb, is the ECU the connection block on the passenger side firewall?

No, the ECU is the big silver thing on the driver side of the block. On an 03 the passenger side box is the PCM.

 

[SWithrow]

When I turn the key to accessory on my 03 the ac compressor clicks on and won't shut off. It started turning itself on and off intermittently, but now does it all the time. Any ideas on what the problem could be? I recently had the ac charged and that did not seem to fix the problem.

Avi

Are you talking about the blower motor? When the truck is turned to accessory position the compressor is not spinning.

I had the same issue, it ended up being the ignition switch connector (located on the left side of the steering colum)the cause for them going bad is the tilt wheel as it puts strain on the wires going into the switch.

 

[JJPage]

No, the ECU is the big silver thing on the driver side of the block. On an 03 the passenger side box is the PCM.

OK, Thanks. Believe I will identify them with a sharpie, memory is fading...

 

[SWithrow]

Is it the blower motor (climate control fan inside the truck) that is running? How is the compressor running when the ignition switch is in the accessory position?

My ignition switch was destroyed due to the arcing at the connectors going into the ignition switch, this happened because of the harness is located at the pivot point of the tilt wheel. When the steering wheel is moved up and down it puts stress on the wire harness and eventually causes the wires to pull on the plug causing an intermittent connection (arcing effect) and sooner or later will burn up your wires and ignition switch.
https://www.turbodieselregister.com/forums/attachments/3rd-generation-ram-forum-no-engine-transmission-discussions/77658d1307316186-hvac-blower-motor-2nd-ignition-switch.jpg

I guess I need to read the whole post before I put my 2 cents in. Sorry for the misunderstanding Avi.

 

[cerberusiam]

How is the compressor running when the ignition switch is in the accessory position?

I think that is what he asking, why is it doing it in the ACC position. Pretty sure he means the AC clutch is engaging and he can hear it click.

 

[SWithrow]

I think that is what he asking, why is it doing it in the ACC position. Pretty sure he means the AC clutch is engaging and he can hear it click.

Thanks, I didn't quite understand what was being said.

 

[AH64ID]

Does it do it with the fan in the off position as well? You aren't in defrost are you?

 

[AWeaver]

hey guys... just doing some digging around here and thought id post my problem for future reference. My TIPM went out on my truck (07 5. 9) and it caused my compressor to eventually fail due to the fact that it never cycled off like its supposed to. This causes high pressures which the compressor is not designed to deal with and will eventually cause it to fail. Dont know what caused the TIPM to fail but it is a $1200 dealer only part unless you can find one at a junk yard or online somewhere. $1800 later I finally have ac again. I was also told that extended idle times could have lead to the failure which could be the case as I work in the oilfield and did idle my truck for extended times before all this happened. Just wanted to post in case anyone else ran into this problem. BTW do not wire around the TIPM... you will burn up your compressor and will have to replace it if you dont have to allready. The TIPM is what cycles the compressor on and off from what I have been told. Please correct me if any of this is wrong... Im just going from what my mechanic has told me.

 

[ASchwartz]

I think that is what he asking, why is it doing it in the ACC position. Pretty sure he means the AC clutch is engaging and he can hear it click.

Sorry, I have been offline and could not respond. Yes, the AC clutch is engaging (audible click) as soon as I turn the ignition to the on position. I beleive I was mistaken when I first posted this. When you turn the key the first position is "ACC", then the next position is "on", and the next position is "start", is that correct? This happens whether the ac button (the one with the snowflake on the dash) is depressed or not. Any ideas as to why??

 

[ASchwartz]

Does it do it with the fan in the off position as well? You aren't in defrost are you?

Yes if the fan is off it still does it, if I don't turn the fan on then after some time the ac coil freezes and won't allow any air thru the vents. The only way to get air thru the vents is to turn the temperature controls to hot and wait for the coil to thaw. Yes, the unit is not on defrost mode.

 

[cerberusiam]

Yes if the fan is off it still does it, if I don't turn the fan on then after some time the ac coil freezes and won't allow any air thru the vents. The only way to get air thru the vents is to turn the temperature controls to hot and wait for the coil to thaw. Yes, the unit is not on defrost mode.

That sounds like either the pressure or temp switch is non-functional and not cycling the compressor correctly. Now exactly where that cycle switch is on these trucks is a good question.



It coul be ECM, PCM, or even FCM.

 

[Bill Stockard]

That sounds like either the pressure or temp switch is non-functional and not cycling the compressor correctly. Now exactly where that cycle switch is on these trucks is a good question.



It coul be ECM, PCM, or even FCM.

According to my '03 Factory Service Manual (FSM), the compressor relay located in the Power Distribution Center (PDC) is controlled by the Powertrain Control Module (PCM) by grounding the coil side of the relay. The PCM respondes to inputs from the A/C Heater mode control, the A/C low pressure switch, and the A/C high pressure switch.



The FSM outlines a three step procedure for testing the relay and a five step relay circuit test.



Bill

 

[ASchwartz]

According to my '03 Factory Service Manual (FSM), the compressor relay located in the Power Distribution Center (PDC) is controlled by the Powertrain Control Module (PCM) by grounding the coil side of the relay. The PCM respondes to inputs from the A/C Heater mode control, the A/C low pressure switch, and the A/C high pressure switch.



The FSM outlines a three step procedure for testing the relay and a five step relay circuit test.



Bill

That sounds complicated