AC Compressor Clutch Won't Kick On


Old 04-03-08, 12:51 PM
Thread Starter
Join Date: Mar 2008
Posts: 16
AC Compressor Clutch Won't Kick On

Hello and thanks for looking at this and all the feedback. The vehicle is a 2000 Chev. S-10 with the 4 cylinder engine. The AC clutch will not engage when you turn on the AC or defrost. It has been working and cooling great. I checked the fuses and they are ok. How about the relay? How do you check that? Any and all other suggestions are greatly appreciated. Have a great day................
Sponsored Links
Old 04-03-08, 01:32 PM
Join Date: Aug 2005
Posts: 2,268
Could be a relay/fuse/and/or low freon levels (which keep the unit from turning on also)...
Old 04-03-08, 01:49 PM
carguyinva's Avatar
Join Date: Nov 2003
Location: Shenandoah Valley
Posts: 1,147
several things have to happen before it will come on. the ECM controls the relay. it must see a signal from the pressure switch (which basically means that the system has refrigerant in it) then when you engage the switch on the dash, that signal goes to the ECM as well. the Ecm will then ground the relay which in turn connects the clutch coil to the battery.

at the relay check for voltage on terminal 3 (hot at all times) on terminal 2 there should be voltage with the key on only.

terminal 5 goes to the compressor clutch could put battery voltage to this one and the clutch should engage proving the wiring to the comp is ok. you can ground terminal 1 and that should turn on the relay (key on engine not running) and this will prove that the relay can work.

as for the rest of the circuit, it gets more involved because the ECM is in the helps to have a scan tool at this point. if you get to this point, i can give you further pinpoint testing but you'll need a schematic, a DVOM and the ability to use it. let us know...

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Thread Tools
Search this Thread
Display Modes