I have a 1999 Blazer RHD problem child, and will most likely have to sell it soon, so trying to get everything fixed up that I have put off (I am too honest of seller, and don't want the "broken" list too long). While trying to figure our a dash light problem (was the dimmer switch) something happened where the A/C clutch does not engage. Have done a lot of research here, and this is how far I am with troubleshooting. Any help would be appreciated. Also found this thread, but don't know enough electrically to know what to test next. https://blazerforum.com/forum/lighti...pressor-62042/


1. IP fuse is fine
2. A/C fuse under hood is fine
3. Swapped relay in fuse box under hood with horn, confirmed horn works with A/C relay and A/C still does not work with horn relay.
4. Low pressure switch is fine, used multi meter to confirm and even jumped the connector. When jumped or the switch connected, the engine RPMs increase as if the clutch was engaging.
5. Put power directly to the connector on the A/C compressor and it engaged. Tested the incoming volts to the A/C compressor and it was zero.
6. Don't think I need to troubleshoot high end switch since the clutch engages with powered directly.


A/C light turns on inside the cab, RPMs increase, didn't blow any other fuses while in the dash, and not sure what to try next. I have a multi meter (just got it two days ago), but don't understand all the lingo/capabilities, so if you would explain simply I would appreciate it! Thank you in advance!

 

No expert but I would think you would need to test the high pressure switch. Since you put power directly to the compressor and it engaged you bypassed that switch. Like a light bulb, if the switch is broken and you run another line directly to it it will work. Disconect it and your back where you started, no light.

 

I don't see where you checked the refrigerant charge. If you are low on refrigerant, the pressure switch will keep it from engaging. Considering the age on the vehicle, a shot of R-134 my get it working again.

 

This might help, the guy did it from a gm circuit

 

Spittybays, that video was a great help! That combined with the diagram I found in a previous post pointed me in the right direction, the wiring under the fuse box under the hood. Found IGN E fuse had no power, found the connector that wasn't attached properly, and "Click" the compressor kicked on. Very happy I don't have to wait for weeks for parts! Thank you very much for the help!

 

Zero dollar fix. Better then sex!

 

Jeff, I think you're doing it wrong

 

lmfao hilarious!