# AC Compressor Clutch not engaging **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** subaru, forester\ **Created:** [May 18, 2023, 11:00pm UTC](https://community.cartalk.com/t/ac-compressor-clutch-not-engaging/190709 "2023-05-18T23:00:14Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![JONATHAN.INABA\_185300](https://avatars.discourse-cdn.com/v4/letter/j/c37758/32.png) [@JONATHAN.INABA\_185300](https://community.cartalk.com/u/JONATHAN.INABA_185300)\ **Post date:** [May 18, 2023, 11:00pm UTC](https://community.cartalk.com/t/ac-compressor-clutch-not-engaging/190709/1 "2023-05-18T23:00:14Z")
Looking for a little help please. The AC Compressor Clutch is not actuating. I tried putting in a different relay and it didn’t work. I tried taking the relay out and jumping it by connecting the 87 and 30 terminals and that didn’t work. Then I connected directly to the coil on the compressor and the positive terminal on the battery and the clutch did actuate. So at least I know the clutch is operational. Now I am trying to figure out why it isn’t actuating when triggered. Any tips on where to look next? Thank you! ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [May 18, 2023, 11:08pm UTC](https://community.cartalk.com/t/ac-compressor-clutch-not-engaging/190709/2 "2023-05-18T23:08:03Z")
If the AC system is low on refrigerant. the compressor clutch won’t engage. Tester ---
**Author:** ![JONATHAN.INABA\_185300](https://avatars.discourse-cdn.com/v4/letter/j/c37758/32.png) [@JONATHAN.INABA\_185300](https://community.cartalk.com/u/JONATHAN.INABA_185300)\ **Post date:** [May 18, 2023, 11:13pm UTC](https://community.cartalk.com/t/ac-compressor-clutch-not-engaging/190709/3 "2023-05-18T23:13:08Z")
Thanks for the quick reply! Shouldn’t the clutch actuate, regardless of refrigerant levels, when the 87 and 30 terminals are manually connected? ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [May 18, 2023, 11:17pm UTC](https://community.cartalk.com/t/ac-compressor-clutch-not-engaging/190709/4 "2023-05-18T23:17:15Z")
There’s a pressure switch in the system that prevents the compressor from damage due to low refrigerant. Tester ---
**Author:** ![Nevada\_545](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nevada_545/32/41232_2.png) [@Nevada\_545](https://community.cartalk.com/u/Nevada_545)\ **Post date:** [May 18, 2023, 11:27pm UTC](https://community.cartalk.com/t/ac-compressor-clutch-not-engaging/190709/5 "2023-05-18T23:27:48Z")
Do you have 12 volts in cavity 87 of the relay box? ---
**Author:** ![bing](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bing/32/4619_2.png) [@bing](https://community.cartalk.com/u/bing)\ **Post date:** [May 20, 2023, 4:21pm UTC](https://community.cartalk.com/t/ac-compressor-clutch-not-engaging/190709/6 "2023-05-20T16:21:25Z")
Yeah like tester said. Somewhere on the metal line there is a pressure sensor with a couple wires going to it. I have had a bad one before so the clutch wouldn’t engage. Or could be low on refrigerant. At least you know the clutch works. Might be a fuse in there someplace too. ---
**Author:** ![Nevada\_545](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nevada_545/32/41232_2.png) [@Nevada\_545](https://community.cartalk.com/u/Nevada_545)\ **Post date:** [May 20, 2023, 4:29pm UTC](https://community.cartalk.com/t/ac-compressor-clutch-not-engaging/190709/7 "2023-05-20T16:29:29Z")
Inserting a jumper wire into the relay socket bypasses the low-pressure cut-out switch. If bypassing the relay does not engage the clutch, the low-pressure cut-out switch is not the problem.