'92 lesabre R12 A/C out of gas since a year

[HotZ28]

No, I was thinking of the clutch relay. BTW, you could follow the wire from the clutch back far enough so you can easily get to a place to strip enough insulation to jump from the battery. It would be nice if you can verify if the clutch will engage with power applied.

[feniks]

nah, haven't done that either. i think i will rather try jumpering it straight to battery (briefly) to see if it engages and starts the compressor to spin. if that works, then i just need to find a cheap replacement part.

new part is ridiculously expensive ($380 up to $800 whcih exceeds the KBB value of my car hahaha!), then junk yards have expensive prices (~$100-200) ... and ebay sellers (also junk yard pulls) seem to sell only automatic hvac control units. emailed a few of them to see if they carry manual controls as well. time will tell.

[feniks]

in case someone else readin this thread is looking for part number info, this is what i got (includes model compatibility):

SPID C67

HEATER AC CONTROL

Mfg p/n 16145214
ACDelco 15-71887

This part is compatible with the following vehicles:

# 1992 BUICK LESABRE V6-231ci 3.8L F/I Vin L
# 1992 BUICK PARK AVENUE V6-231ci 3.8L F/I Vin L
# 1992 BUICK PARK AVENUE ULTRA V6-231ci 3.8L F/I Supercharged Vin 1 (ULTRA)
# 1993 BUICK LESABRE V6-231ci 3.8L F/I Vin L
# 1993 BUICK PARK AVENUE V6-231ci 3.8L F/I Vin L
# 1993 BUICK PARK AVENUE ULTRA V6-231ci 3.8L F/I Supercharged Vin 1 (ULTRA)
# 1994 BUICK LESABRE V6-231ci 3.8L F/I Vin L
# 1994 BUICK PARK AVENUE V6-231ci 3.8L F/I Vin L
# 1994 BUICK PARK AVENUE ULTRA V6-231ci 3.8L F/I Supercharged Vin 1 (ULTRA)

[feniks]

ok. did not have time to play with ac clutch electrical connector, so i jumpered the ac clutch relay socket (and accumulator low pressure switch just to be sure) and violla compressor started spinning



i need a cheap replacement HVAC module (heater ac control as above).

[spinne1]

To get your control unit out, do the following:
1. Pull straight back on both fake wood trim pieces running along the middle of the dash. They will come out. Grab the end side first and give it a tug.
2. Open your glove box and remove the two screws on the top left and right.
3. Take a flat head screwdriver and put it just above each ac vent's moveable part (the whole black piece) and put it in about 1/2 inch or so and push down while pulling back the top with your fingers until it snaps out of its holder. It helps to have the vent not straight, but turned partially to one side or the other. You can then pull the vent out from the top with your fingers.
4. Once all four vents are out use a 7mm socket, OR a T-15 Torx screwdriver and remove the four screws inside and along the top wall of the vent holes.
5. Remove the two or three screws holding the bottom of the glove box to the dash (note: do not remove the door of the glove box from the glove box) They are under where the fake wood trim used to be.
6. With the glove box out, you now focus on the large black trim/dash piece that is covering the radio/heat control/instrument cluster area/etc.
7. Remove all screws holding the large black plastic piece to the dash where the wood trim used to be. There are about 4-5 screws in the this area total. There are two to the left of the steering wheel (I think) and three to the right (I think.)
8. There are still two screws to remove above the steering wheel and instrument cluster (speedometer area.) See two holes on the "ceiling" of the black piece? Take those two screws out.
9. Put your key in the ignition, foot on the brake, turn key to run position, put car in 1 gear (all the way down,) tilt the steering wheel all the way down, and remove the large black plastic piece that is the left side of your dash.
10. You now have open access to your ac control unit. There are three screws holding it in place.
11. Once the screws are out remove the wire harnesses from the back.

But, before removing it test it. How? Too long to describe here but it is all in the factory service manuals. Get them off ebay. There is a regular manual and an ESM. Both make up the complete "service manual." There are specific tests in the manual for the head unit. It is better to test it than blindly replace it. And you will likely use the manuals much if you retain this car for a while.

[HotZ28]

Disconnect the jumper on the pressure switch and see if the compressor will still engage. BTW, the control unit will not command the compressor relay to engage unless low line pressure is within operating range. Question is, what is the low side pressure, have you checked that?

[feniks]

Originally Posted by HotZ28

Disconnect the jumper on the pressure switch and see if the compressor will still engage.

yes it does.

[feniks]

spinne1 thanks for detailed instructions on head unit removal!!

[feniks]

Originally Posted by HotZ28

BTW, the control unit will not command the compressor relay to engage unless low line pressure is within operating range. Question is, what is the low side pressure, have you checked that?

i don't know, haven't checked the pressure on low side with compressor spinning. later on may try again, it's too hot now (97F) in Jersey ...

[feniks]

soooo, i checked the pressure on port on pipe (by accumulator but not on it) and it reads zero ...

then tried adding more gas (got last can of freeze 12 left) but i lost the can fitting ... hehe funny ... went to autozone to see if they carry such things, but they were closed already (4th of july) ... and locked myself out of car (left door key inside) LOL... good thing a friend was staying home, so he cam to aid me, eventually (with his tools) we were able to open the car without breaking glass, i lost only piece of chrome trim around driver rear door, put it back on duck tape haha LOL (this car looks like shit anyways hehe) ... then we went drinking to celebrate the happy end ... what a story

in morning, will try finding the gas can fitting and adding gas to a/c (with compressor spinning), maybe my gauge is broken (a/c starts with jumpered relay, no need to jumper low pressure switch). need to take some sleep, will post back in a few.

[HotZ28]

If the compressor spins with the connector to the pressure switch connected (not jumped); that would indicate the system pressure is within range, (unless the switch is bad.) When the compressor is engaged, do you have cool vent air? In addition, it sounds like your gage should be verified for accuracy. Normally on an R12 system, (with compressor engaged) & system stabilized for 10-min, the low side pressure of a filled system should range between 30-34 psi. and the accumulator would be very cold to the touch, along with visible signs of sweating.

[feniks]

well no happy end here after all. i found the gas can fitting and loaded last can of Freeze 12 into the system on spinning compressor (after like 15 mins of cycling with a shorted relay).

a/c started working a little, but only temporarily unfortunately. pressure readin was low like 10-15psi (on running system at full blast).
once i shut down the engine (like 30 mins later) i heard a loud hissing noise from compressor area. then i restarted it (with normal relay, no more jumpered) and saw compressor engaging by itself, though after i took it for a short highway walk all the gas leaked out. pressure zero again, and compressor does not engage by itself again (no gas again).

this ac system is beyond cheap fix methods, the compressor unit (or some seals) would need a replacement and i'm not going to do it.
will have to live with it until i junk/sell this car.

thanks for all your help guys! appreciate it very much. now i know what i am standing on.

[HotZ28]

It sounds like the high pressure relief valve opened, an indication of a clogged expansion valve (orifice screen). More than likely, the compressor is worn out & spewing contamination throughout the system (Black Death)!

[feniks]

i agree the compressor sound like a real problem (internally). also heard sort of a ticking when compressor was cycling with almost no gas/pressure before loading freeze 12.
also once i started loading freeze 12 the compressor started running more quiet, but it did something crazy, like it spit (internally) and it caused almost the whole engine to stall (almost) then it all started running (until gas leaked out). maybe even some gasket got blown.

either way i'm not pursuing it any further that this