Tracking down A/C issue

dwinters14

Member
Joined
Apr 10, 2020
Posts
36
Reaction score
16
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

Full Access Member
Joined
May 14, 2017
Posts
1,053
Reaction score
724
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

Member
Joined
Apr 10, 2020
Posts
36
Reaction score
16
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

Full Access Member
Joined
May 14, 2017
Posts
1,053
Reaction score
724
Add some flourescent dye to the system and a couple cans. Look for leak.
You must be logged in to see this image or video!
 

Cbncanada

Member
Joined
Apr 10, 2020
Posts
47
Reaction score
21
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

Member
Joined
Apr 10, 2020
Posts
36
Reaction score
16
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

Full Access Member
Joined
May 14, 2017
Posts
1,053
Reaction score
724
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

Full Access Member
Joined
Dec 29, 2016
Posts
1,043
Reaction score
553
Location
Indiana (formerly IL)
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.
 

Forum statistics

Threads
113,148
Posts
1,538,117
Members
69,801
Latest member
mandop86
Top