Love ur youtube channel 2005 chevy colorado ac compressor not starting fuse is good relay is good no power at compressor plug but a good ground. Any ideas
Have you hooked up a manifold gauge set to see if there is sufficient pressure in the system to allow the compressor to run? After 20 years it would be no surprise if refrigerant was low.
Also, for future reference please put your question in the body of your post, not the title line which is meant for a short description. Thank you.
@chucktobias yea low side had kinda high pressure like 50psi
High side was low like 20psi
@chucktobias trying to figure this forum out not the best on phones. just an old school welder/piper but thx for the help. If u got welding ?s I can probably help. Just saying
No problem, just making you aware of it. Sometimes people put so much into the title line that details get cut off since there is a limit on the length allowed.
low side had kinda high pressure like 50psi
High side was low like 20psi
When the system is off the pressure would normally equalize on both sides. I'm wondering if maybe you have a restriction somewhere, but that wouldn't stop the compressor from running.
On most cars the low-pressure safety switch turns off the compressor if the low side goes below around 20 PSI so you have enough pressure for the compressor to engage, but it's always possible the low pressure switch is defective or there's a wiring problem. You should be able to check that with a multimeter.
Some vehicles have a diode inline with the compressor clutch coil wiring to prevent voltage spikes backfeeding into the HVAC module. If that burns out obviously you won't see any voltage at the clutch coil. Is the clutch coil itself good? (Does the clutch engage if you briefly hot-wire it directly to +12V?)
It's possible you're looking at a computer module problem but you would need a Tech2 or equivalent bidirectional scan too to test that. Also HVAC switches and controls could be faulty.
There are a lot of things that can cause the AC to fail. You can find a repair manual for that vehicle at the link below which may help:
https://charm.li/Chevrolet/2005/
@chucktobias going to try and jump it tomorrow
I have a autel 906 bt scan tool but no codes for ac problems.
What do mean by by-directional. Also it does have a diode in fuse box looks like a fuse but only fits in 1 way
How do I test it
Bi-directional means you use the scan tool to command the computer to operate various functions in order to test them. You can test diodes with a multimeter. They should conduct in only one direction. (I'm sure there are youtube videos showing how to do it.) Or you could simply see if there is voltage present before the diode when the AC is turned on.
@chucktobias got a hayes and chilton books coming. I've never had a lot of luck with them but they were cheap on ebay so y nor. Scan tool has component test and live data but nothing came up for any ac components. My caddy u can check all that [expletive deleted]. But this I couldn't find anything. I'm not the best with that tool anyways. It had helped my figure a lot of stuff out. Mostly emission and evap stuff
Please watch language, this is a family friendly forum and swearing is against the forum rules which are posted in a topic near the top of the main page.
You may find the repair manuals at charm.li are more complete than Haynes or Chilton, which I've found to be pretty useless for anything much newer than the 1970s.
You're going to need to work with a wiring diagram and trace the compressor clutch wiring with a test light or voltmeter to see where the voltage stops. If you get as far as the HVAC control module then the computer is not turning on the compressor. That's a situation where you can use a sufficiently advanced scan tool to electronically command the AC on even if the control switches are not working.
@chucktobias ok sorry won't cuss anymore.
I have a wiring diagram trying to figure it out as we speak