A/C issues 5.7l 2nd gen

Couldn't find it in the threads already and I don't have it figured out.

Initial symptom: highway driving with A/C on, started blinking and went warm on me.

Poked with a stick: Fuses are good, relays are good. Can't get a good read on the charge pressure because the compressor won't engage.

Fiddled with it for a bit trying to get the compressor to engage, no sparks or anything crazy, but I tried more than a few times and it sent a burning smell through the cab and engine bay. Friction by the smell of it.

Worked immaculate prior. 195k miles. Am I SOL? I'm an engine guy, zero familiarity with diagnostic of HVAC , never had to deal with it.

 

I think this is a blend door issue. Its been brought up before.

 

Would that cause the compressor to not engage though?
I do have the blend door creaking noise upon startup, and come to think of it I'm not sure I've heard it lately

 

Actually, it still changes freely from zone to zone so wouldn't it not be that?

 

Zone to zone, meaning hot and cold or where the air goes?

 

It still switches from vent/floor/defrost etc. Heater blows hot still as well

 

Your coolant is low; maybe a pinhole leak, maybe a hose or fitting gave out (...it is a 2nd gen so it has obviously been on the road for a minute...). The trucks get so old that rubber/plastic components tend to give out over time simply due to age - had same issue/s with my '08. Once you get a sufficient amount of coolant pressure in the line the compressor will likely re-engage so the quick/easy fix is to grab a canned recharge with attached gauge from Wal-Mart or something. The RIGHT recommendation would be to take it to a shop to diagnose for leak source and repair correctly. Good luck, summer is coming!

 

Get the recharge can with dye in it so when it leaks out again you can look for leaks in the system with a black light.