AC pump clutch NOT engaging (help)

**wastedincome** · 07-24-2012, 04:36 PM

Well I was getting ready to bring my e34 in for recharge and was givng the system a look over. Made sure aux fan comes on, etc. WELL I noticed that the clutch is NOT engaging with the AC on

I'm not sure if its seized (doesn't look it) or if there is a relay or something not allowing it to engage. I'm not that good when it come to AC repair

**jehu** · 07-24-2012, 04:40 PM

The clutch won't engage If the system is too low on refreigerant I think , maybe I remember incorrectly..... do you have any idea about the fill level ?

I couldn't drive around in this heat without the frostly AC I enjoy

I kind of think the switch on top of the Receiver/Dryer has something to do with sensing for refrigerant pressure..

**cornflakecwl** · 07-24-2012, 04:50 PM

Correct, the clutch will not engage if the system is low on refrigerant. Best thing to do is take it to someone who has the proper AC Refill/Reclaim unit as they can vacuum test the system for leaks and then you know if its worth filling it or not. THEN you can see if there is a problem with the compressor but it's likely just because there is no pressure in the system.

**wastedincome** · 07-24-2012, 04:52 PM

Originally Posted by jehu

The clutch won't engage If the system is too low on refreigerant I think , maybe I remember incorrectly..... do you have any idea about the fill level ?

I couldn't drive around in this heat without the frostly AC I enjoy

I kind of think the switch on top of the Receiver/Dryer has something to do with sensing for refrigerant pressure..

Thanks that does make sense and sound right. Is there a relay that can be jumped to test the clutch??? Ya its been hot as hell here (as u know

) And I've been spoiled by driving my e38 w/ cold AC. I forgot that my blk on blk e34=HOTTER then hell

**sticky280zx** · 07-24-2012, 04:56 PM

shoooot was 105 here saturday, and even with the orient/tan its still too hot with no tint (even with decent a/c)

**dinanstu** · 07-24-2012, 04:57 PM

Check the pressure level first from a proper A/C guy..usually its a leak.

If the A/C system would kick out after getting hot, and then gradually got worse and eventually failed it could be the shims in the magnetic clutch are too worn.

**wastedincome** · 07-24-2012, 05:03 PM

Originally Posted by cornflakecwl

Correct, the clutch will not engage if the system is low on refrigerant. Best thing to do is take it to someone who has the proper AC Refill/Reclaim unit as they can vacuum test the system for leaks and then you know if its worth filling it or not. THEN you can see if there is a problem with the compressor but it's likely just because there is no pressure in the system.

Thanks CF, I was planning on taking it to a proper AC shop for filling and was just trying to check everything prior as I have hard time trusting almost any shop

Originally Posted by dinanstu

Check the pressure level first from a proper A/C guy..usually its a leak.

If the A/C system would kick out after getting hot, and then gradually got worse and eventually failed it could be the shims in the magnetic clutch are too worn.

SO, If I have it leak tested and charged up but still wont engage clutch I should look into the clutch shims???

**jehu** · 07-24-2012, 05:08 PM

its the yellow relay in the fuse box under the hood neasrest the fuses and windshield

**wastedincome** · 07-24-2012, 05:23 PM

Originally Posted by jehu

its the yellow relay in the fuse box under the hood neasrest the fuses and windshield

Thanks, I just ran out to check it and that f'er is STUCK

Came back upstairs to grab beer try again

Starting to think a problem may lie within the relay.

**jehu** · 07-24-2012, 05:29 PM

Originally Posted by wastedincome

Thanks, I just ran out to check it and that f'er is STUCK

Came back upstairs to grab beer try again

Starting to think a problem may lie within the relay.

Mine showed signs of overamping... browning on the relay and the white plastic where it plugs in...

btw I think I have a good one and have nothing going on tonight... maybe we could meet halfway somewhere and try it out.. I'm over in Milford

**wastedincome** · 07-24-2012, 05:40 PM

Originally Posted by jehu

Mine showed signs of overamping... browning on the relay and the white plastic where it plugs in...

btw I think I have a good one and have nothing going on tonight... maybe we could meet halfway somewhere and try it out.. I'm over in Milford

Well looks like mine is beyond the "browning stage" more like CHARD

What would be the CAUSE of this????

Wicked thanks for the offer Jehu, But I have 2 donor cars near by

I MUST find the cause for this issue. Also, any idea what pins get jumped to test the compressor clutch??

**TSMacNeil** · 07-24-2012, 05:52 PM

I'm not familiar with that particular relay, but a barbeque'd socket indicates one of a few things:

1) loose connection at that particular socket...makes it get very hot.
2) Excessive amperage draw (possibly from a seized compressor/clutch)...
3) Relay has gone T.U. and drawn current(amps) through it

Make sure that compressor still spins and the clutch engages before you address the relay/socket.

**wastedincome** · 07-24-2012, 06:15 PM

Originally Posted by TSMacNeil

I'm not familiar with that particular relay, but a barbeque'd socket indicates one of a few things:

1) loose connection at that particular socket...makes it get very hot.
2) Excessive amperage draw (possibly from a seized compressor/clutch)...
3) Relay has gone T.U. and drawn current(amps) through it

Make sure that compressor still spins and the clutch engages before you address the relay/socket.

Thanks for the advice. #3 what IS gone TU?? (bad?) The compessor spin no problem as its had a belt on it always. When I first got the car (few yrs back I think) the AC seemed kinda cold but I realized the aux fan was seized. SO I replaced the fan and AC wasn't any better BUT it was end of season for the car. SO next season I kinda just forgot and didn't care at the time (m-tech body kit and other mods took priority

)

**paperplane94** · 07-24-2012, 08:35 PM

T.U. means that it died.

You need to jumper the switch at the receiver/drier while its idling and see if the compressor clutch comes on.

**wastedincome** · 07-24-2012, 08:50 PM

Originally Posted by paperplane94

T.U. means that it died.

You need to jumper the switch at the receiver/drier while its idling and see if the compressor clutch comes on.

YA, I figured TU=tits up=bad, lol. where is switch u mention??

**funfunfer** · 07-25-2012, 10:52 AM

Switch is on the receiver/dryer tank below the windscreen washer tank on my E34 M5. This also ties into the aux fan circuit (i think). Check Bently to see shich wires to jump. I had to do this in order to recharge my system.

**wastedincome** · 07-25-2012, 01:19 PM

Originally Posted by funfunfer

Switch is on the receiver/dryer tank below the windscreen washer tank on my E34 M5. This also ties into the aux fan circuit (i think). Check Bently to see shich wires to jump. I had to do this in order to recharge my system.

Ok, I know my aux is working when turn ac button on. I'll check Bentley when get home

UPDATE: after reading the bentley diagram leaves me more confused

It shows the compressor relay as being 4 pin yet the cooked relay I found has 5 ?!?!? My aux fam was previously seized, could that have fried this relay???

**wastedincome** · 07-27-2012, 03:45 PM

Well I found out that the yellow relay I found that was cooked is my BLOWER relay not my AC relay!?!?!? Whats strange is I've never had a issue with my blower since I've owned it?!?! kinda really confused now

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