AC in my truck stopped blowing cold - basic troubleshooting has not helped
I went to drive my truck yesterday and no longer had cold blowing AC, which is just awesome when you live in Phoenix! The fans come on inside, but it just blows hot air. I'm pretty sure it was working fine Sunday, but I only drove it short distances up the street and may not have used it. It was definitely working and blowing cold Saturday, but when I went to drive it yesterday, no cold air at all.
The truck is a 02 Ranger 4.0L, here's my troubleshooting from last night:
-Popped the hood and found the clutch isn't engaging on the compressor, but I can still turn the compressor clutch by hand.
-No popped fuses (panel on left side of dash), and the relay (box under the hood, drivers side near windshield) seems to be okay. I swapped it with another, didn't fix the problem.
So with the car running and AC on max...
-I hooked up a refrigerant gauge to the low pressure side and it read ~140psi. I read this high of a reading is normal if the compressor is not running and shows there's enough pressure to active the switch and kick on the compressor.
-I put a jumper wire across the lower pressure plug, but the compressor still didn't kick on
-High pressure sensor switch is reading ~13.5v
-Clutch wires on the compressor read no voltage (even with low pressure switch jumpered)
I was starting to think the clutch coil on the compressor failed, but if that was the case, shouldn't I still be seeing voltage across the plug for the clutch wires? I feel like the lack of voltage here is my problem, and the signal to engage the clutch just isn't being sent. but I tried jumping the plug on the low pressure side (where the signal comes from, right?) and the clutch on the compressor still didn't engage. Any ideas? When I get home today, I'll start looking more at the electrical side (ugh). Just wanted to bounce some ideas off you guys in the mean time.
Thanks for any help guys!
Last edited by bleeatch; 07-30-2013 at 10:08 PM.