A/C quit

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uninformed
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A/C quit

Postby uninformed » Sat Oct 05, 2019 4:41 pm

2006 Dodge 2500 4x4

I really want to do my own repairs when possible.

I was on the way home, the A/C was working great. I stopped at the store for 10 mins. and when I started the truck again.....no cold air at all.
I have since bought some gauges. Static pressure was around 90 lbs. on both sides. I checked the clutch with the engine running and the a/c in the on position. Clutch does not engage.

My 'Service Manual', not the owners manual, says to check fuse, (fuse is good) the service manual then says to check with a scan tool. I don't have a scan tool which in all likelihood would be more than the $250.00 scan tools at the auto store.

I am ready to replace the compressor with clutch but how do I know if the system is contaminated and needs flushed/replaced??
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bohica2xo
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Re: A/C quit

Postby bohica2xo » Sat Oct 05, 2019 6:02 pm

Check and adjust the clutch gap first, before you try replacing parts. Gap should be less than .020 or 0.5mm
uninformed
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Re: A/C quit

Postby uninformed » Sat Oct 05, 2019 9:31 pm

bohica2xo wrote:Check and adjust the clutch gap first, before you try replacing parts. Gap should be less than .020 or 0.5mm


bohica2xo-- I checked the gap and it is 0.38 mm which is within the limits according to Dodge Service manual which allows 0.35 to 0.60mm or .014 to .024 in.
I think my biggest concern is knowing how to tell if the system needs to be flushed and the condenser replaced because of compressor failure.
With the engine off, I can turn the compressor but it feels like there are a couple of detents as I rotate the compressor shaft, which seems
strange to me.
I really appreciate the input.
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Cusser
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Re: A/C quit

Postby Cusser » Sat Oct 05, 2019 10:11 pm

First check to see if the AC clutch is even getting positive voltage when AC is switched on. No positive voltage there means no clutch engagement.
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bohica2xo
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Re: A/C quit

Postby bohica2xo » Sun Oct 06, 2019 7:48 am

Yeah, the clutch shaft should turn without notches or detents. The torque may change a little but it should be smooth.

The condenser in those trucks is a parallel flow with small tubes. Very effective, but easy to clog. A condenser replacement is always a judgement call, based on what sort of failure mode you see. But at 13 years old I would probably just replace the condenser - it is the primary filter in the system.

Flushing the lines and evaporator allows you to get to zero oil in the system so that you can add the proper oil charge without guesswork. But you have to be sure you get all of the flushing agent out - or it can do more harm than good.

The dryer of course gets replaced.

The fact that you get no clutch engagement with a proper gap is something you should probably diagnose & fix while you still have pressure in the system. Clutch relay is usually where I start. Pull it and use a jumper to see if the clutch will engage - briefly. Next, swap with a known good relay and see if it engages.
If the relay fixes it, great. If not the cycling switch / pressure sensor is the next suspect.
uninformed
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Re: A/C quit

Postby uninformed » Sun Oct 06, 2019 7:46 pm

bohica2xo

Your info is more than appreciated.
Price-wise I believe it is best to follow your suggestions and replace the components, (which makes a lot of sense), however, I am actually left feeling ignorant because I've been completely duped for the last hour or so trying to unplug the connector to the compressor.

From underneath, it is almost beyond reach....especially with two hands and I simply cannot figure out the secret to pushing, pulling, jabbing, twisting, leveraging, sticking, stabbing or otherwise doing what it takes to break the connection to the compressor. I am sure it's simple but it has left me frustrated.
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bohica2xo
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Re: A/C quit

Postby bohica2xo » Mon Oct 07, 2019 5:14 pm

So no clutch pull in with a jumper in the relay socket?

You can check the clutch coil resistance from the relay socket. Starting on "volts" with your DMM, key on. Probe the relay socket for voltage to ground. The terminal with +12v is connected to the battery. So the OTHER terminal is the load or clutch. Switch to Ohms and check that terminal to ground - should be 4 to 6 ohms.
uninformed
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Re: A/C quit

Postby uninformed » Tue Oct 08, 2019 11:06 am

Yeah, I wanted to do that from the get-go but my tipm does not have relays, only fuses and a couple of other things that look nothing like a relay to me.
:D
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bohica2xo
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Re: A/C quit

Postby bohica2xo » Tue Oct 08, 2019 9:00 pm

It has a relay in that circuit. Dodge used a Power boxy that looked like a piano, with relays inside...
https://www.factorychryslerparts.com/images/parts/Chrysler/fullsize/00i99257.jpg

But they sometimes used a rectangular box with fuses, with relays behind it
https://www.youtube.com/watch?v=Y4iF0jAW30Q
uninformed
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Re: A/C quit

Postby uninformed » Tue Oct 08, 2019 9:37 pm

Wow, I have to check this out.
Thanks for the heads-up.

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