A/C no output

[RGH43]

Where is the relay located, trying to check if the clutch is getting voltage, checked the clutch and it rotates freely. Fuse is OK. A/C lite comes on & the Fan kicks up speed but no cold air. I found comments on the internet about several owners having the same issue and the cause was a bad TIPM. At least one was able to have it flashed and that fixed the A/C. How or where would or could you check for voltage going to the A/C?

 

[Tuesdak]

If both of the evaporator pipes are getting cold you may have a broken blend door. Pipes not cold: You can look at the AC clutch and see if it's spinning. Yes: it may be low or out of R134a and needs a recharge.

 

[Killer223]

with engine running is the clutch engaging? you can jump the low pressure switch to make the clutch engage.

 

[RGH43]

with engine running is the clutch engaging? you can jump the low pressure switch to make the clutch engage.

The pipes are not cold as the clutch doesn't engage.
Clutch rotates freely by hand but the Clutch is not spinning nor do I hear it engage at all while engine is running. Where is the low pressure switch located and how do I jump it? If the system is low on R134a does that mean it is leaking somewhere or is this just normal over time? I don't see any residue in the D/W where it is parked. The compressor is located on the Left side of the engine at the bottom and looks like I would have to remove the the Fender Well to get at it very easily & most likely remove the front tire. Is there someplace to get to the wiring easily to check the voltage.Is there anyplace to get a diagram of the A/C system online.

 

[mwilson]

What year is your truck??

My experience is with an ‘06 and with that being said..

If your clutch is going bad the TIPM will trip to protect itself from the increased electrical draw..

Was it working well and then suddenly it quit working?

 

[DavidC]

with engine running is the clutch engaging? you can jump the low pressure switch to make the clutch engage.

Last time I tried to help with an 06 the switch is not there anymore as he had 3 wires to what I assume is a pressure transducer, anyone know if this is the case ?.

 

[RGH43]

What year is your truck?

My experience is with an ‘06 and with that being said..

If your clutch is going bad the TIPM will trip to protect itself from the increased electrical draw..

Was it working well and then suddenly it quit working?

Yes it was working fine, the truck is a 2007 5.9L, last of the breed. The 06 seems to have a different Fuse box than the 07, I don't have a relay switch in the box. What I can find out it seems to be part of the box now on the 07 so I would have to replace the box if that is the issue. Several hundred dollars for a new TIPM.

 

[mwilson]

Right, but it’s probably still designed to trip out in order to protect itself from a shorted coil in the A/C clutch. It will not reset itself...

But the dealer can reset it.

What I did was verify my system was charged when it suddenly quit engaging one fine summer day two years ago...

So I had the dealer check power to the clutch while I had it in for the passenger side air bag recall. No power so I had them reset the TIPM and leave the clutch unplugged. That way it was ready to go when I changed out the clutch and plugged it back in...

 

[RGH43]

Thanks for the info, does anyone know how difficult it is to change the clutch out yourself. Come out easily, need any special tools etc. I would still like to check the clutch to see if it is getting voltage. Need to know where the low pressure switch is and how to check it for voltage.

 

[mwilson]

I’ve done it..

https://www.turbodieselregister.com/threads/a-c-clutch-change-06-09-trucks.259539/#post-2521315

 

[Tuesdak]

I don't believe Dodge uses a low pressure switch like GM. They have a pressure sensor on the high side that may or may not trip off at low pressure from a loss of R134a charge. Instead of a low side switch Dodge uses a temp sensor to keep the evaporator from freezing up. This said you can unplug the compressor clutch and ohm it out.

You can inspect the clutch and if it looks as bad as @mwilson you might consider just replacing the compressor. My clutch was so hot from grinding it hurt the shaft seal to the point of leaking. (A drive strap broke on the clutch and turned it blue.) There are a lot of garbage knock-off C H E A P compressors out there that fail or leak in 1 season. Look up the OEM compressor and get it from the OEM manufacturer or MOPAR.