Tracking down A/C issue

[dwinters14]

Hey all,

My a/c isn't working and I need help narrowing it down. My trucks heat and a/c both weren't working, which ended up being a bad door actuator. I replaced that, reset the HVAC controller and the heat was working, but not the A/C. My rad blew up and I took it to a shop to fix. They said my A/c was low on free-on and put in 3 lbs. The a/c worked and was cold.

Fast forward to it being summer and it's hot out. I go to turn on my a/c and no cool air, in the evening i tried my heat, and again ambient air. So i reprogrammed the controller again, and my heat is working again, but no a/c. A friend of mine and I hooked up the a/c gauges and found pressure, I'm just not sure how much. The compressor kicked on, as well as the fans, but again no a/c.

I think there's a leak, but everything I'm reading about online is saying I have to take it to shop so they can use that expensive machine.

 

[exp500]

With compressor running, follow discharge hose over to receiver/dryer/expansion valve/evaporator. Feeling coldness. If cold problem probably inside. A good scanner could test.

 

[dwinters14]

To follow up, I turned on the truck, set the front and rear climate control to full blast at 60 degrees. I went to the engine bay and the compressor didn't kick on, nor did the fans air was blowing in the interior. I believe a relay/voltage test from the fuse box is probably next plan of action.

 

[exp500]

Add some flourescent dye to the system and a couple cans. Look for leak.

 

[Cbncanada]

The A/C lines running to the rear are often a culprit for leaks. They factory lines run along the frame on the right side and get corroded easily.

 

[dwinters14]

Add some flourescent dye to the system and a couple cans. Look for leak.View attachment 303281

I'll give this a shot and report back

 

[dwinters14]

So I checked the compressor fuse and it was fine, and I swapped relays with the one beside it, and the compressor clutch is now engaging. It clicks on every 15-30 seconds or so, but still no A/C and the fans behind the rad aren't turning on. I ran it for a few minutes to see if anything would change but it didn't.

I know there's still r134a in the system because I poked the shraeder valve on the low side (valve closest to the firewall) and a bunch of green liquid sprayed out. Now correct me if I'm wrong, but shouldn't that side be gas?

 

[exp500]

Some in the system allows pump to run till nothing there, so 5-20 seconds. Add a couple cans try to match chart lowest pressures for temp.(less likely to overfill.) The green is dye, so push that around awhile and look for leak. Wash off low side fitting well. known for slow leaks there. check condenser, all fittings, and gaskets to start with. Thats the cheap way $5 per can. When compressor runs you can try inside controls.

 

[rockola1971]

First most likely leak is right at the low side schraeder valve. Get the tool to tighten it. Need to know what your PSI is on the low side with compressor engaged. If compressor isnt engaged thats likely because system pressure is too low. There is a cutoff sensor for low pressure.

 

[TheAutumnWind]

Youve got access to gauges. Use em. If you dont know the pressures you cant diagnose.