My ac quite working. Clutch not engaging.  Checked for a code. None found. Checked continuity through hi pressure switch and clutch circuit. OK  Checked clutch physically with  external  12 volts. Clutch engaged. Any suggestions??  Where can I find a schematic of the ac circuit?

How about freon in the system? Is there at least 60-90 PSI of freon on the low side?

 

Electrical - How about the A/C relay is it good? Fuse J (10 Amp) is it blown? Is the compressor clutch got a open circuit? (Ohm test)

Low pressure switch will also keep the clutch from engaging.

Swap relays. Thats the most limey cause if the clutch stopped but is still functional worth 12v.

Did continuity with ohm meter through clutch and (I think hi limit switch ? near compressor on hi side tube) Applied 12v to clutch. It engaged. 10 amp fuse ok power on both sides. Where is low pressure switch? Have pressure on low side. Where is the AC relay found? where is low pressure sw found?/ is there a scematic?

The relay is in the junction and fuse box on the drivers side inner fender under the hood.

The relay is in the junction and fuse box on the drivers side inner fender under the hood.

Thanks ! Gives me another place to start looking.

So what was you static pressure of freon? I'll dig up the schematic tomorrow morning.

So what was you static pressure of freon? I'll dig up the schematic tomorrow morning. Have to go back and check that. Top of my head 40psi?? Will check that in AM

Too low. Typical I see like 70-90 PSI just at rest for Dodge trucks. You might see variance because of current temps.

two switches, one on the accumulator, the other is on the outlet tube right at the back of the compressor. i recently tested mine and troubleshot by paperclipping the plugs to the switches closed which closes the relay, i got 12v to the clutch plug. i tried hot jumping the clutch directly from the battery and nothing so i get to replace the compressor

Should have said I have had a slow leak problem since new. Usually add a can twice a year before it gets to low. Jumpered the low press switch and clutch engaged. Added 2 cans. Cools great now. Dealer had it 12 times and couldn't find the leak. I have tried the leak ck Freon with dye. No help. Anyone try the R134 with stop leak? Are there leak detectors that I could rent? Thanks for your help

I just added a can yesterday. I get about a month out of a can before it gets borderline not cold enough. I use a cheap can and one with oil the next time. If I get some time this summer, I'll do the evap with Mike's video.

Before doing all that I would do the o-ring seals first. Also I would also add a shot of UV dye and use a black light to find the leak. Like my last chase I finally found the leak on a 2001 Subaru. The compressor failed.

 

 

 

 

Cool pic!

Thanx... That Subaru was driving me crazy. She admitted o me that she been adding freon and the span was getting shorter and shorter between recharging. I started out with a basic recharge and added dye to the system. Ask her to drive with the A/C on as much as possible to push the dye around. She just left it parked most of the time. So it came back I added even more dye and small amount of freon to hopefully get it to push out. Left it run for over 30 minutes with the A/C black lighted it that evening and nothing. Got up the next morning and black lighted again PRESTO the green stood out like a sore thumb you could miss it.

 

So that being said I would add the dye to the air conditioning system recharge it like normal. The drive it around for a few days. Every evening in the dark break out the black light and check all the joints for green to show up. I know NAPA sells the black light flashlight.

 

Here you go.

https://www.google.com/#q=black+light+flashlight&tbm=shop

 

As for the photo any digital camera can see UV. Just shine your TV remote at your digital camera and you can see the LED light up in the camera but you can't with the naked eye... (Mopar1973Man Trick)

Front compressor seal leaks are very common on passenger vehicle dye is an excellent way to find it as mike showed.

I have used dye in hydraulic and fuel systems to find slow leaks many times as well as trying to nail down fluid transfer issues from one component to another, it is a very handy tool at times.

Like my compressor failed on the shaft seal. I never did find dye anywhere in the evaporator, lines, pressure switches, condenser, etc. So I replaced my compressor and 3 years of leak free A/C now and wonderfully cold. So cold at times you have to roll down the windows to warm up again.

Do our trucks have an AC air filter on them?  I've looked but haven't found one. 

If You mean cabin air filter then no, but the 4th gens have a spot in the air box for one but do not come from OEM with a hole or cover for it to which I added that mod to my 2010 long before Genos started selling the kit.

http://www.genosgarage.com/DODGE-RAM-CABIN-AIR-FILTER-KIT-10-15/productinfo/GG-CFF1012/#.VU9V87B0yUk

No. There is no filter for the HVAC system. The best thing you can do is run MAX A/C setting. That only draws inside air. Where all other setting draw outside air.