93-Z34 Lumina AC ??

[wayne petty]

PLEASE be careful if you intend of JUMPING the compressor clutch coil...

sometimes..    they are diode protected..   inside .. sometimes the diode is in the connector that you unplug with the end of the harness..

hook it up backwards..     by by diode protection..

just curious.. what is the 10th digit of the VIN number.


or the production date off the door sticker..  month and year...

or both...

with the 3.4 motor it is probably a 94 not a 93..  and the AC clutch is computer controlled probably by a relay stashed under the hood someplace... '

[34ford]

Well guys I woke up early this morning and checked out some things on the car.

Mikej: we put 2 full cans of freon in the system after vacuuming it down. Yes there is power to the pressure switch. (Wayne, if I remember it was something like 5 to 6 volts.)  Don't remember if we checked the power to the compressor.

Wayne: It is a 1993. Yes it has a relay for the ac clutch located on the passenger inner fender well with the other 2 for the cooling fans. Swaped it with one from one of the cooling fans and no change.

The fuse for the clutch is good as well as another listed for the HVAC.

I did disconnest he battery and hooked it back up and no change.  Will check for codes next.

thanks again

bob

[wayne petty]

let me go over some of the components...

this is the AC system pressure SENDER..  not an on off switch.. this is a variable output..   its usually on a high pressure line as i recall.. after the condenser..

http://contentinfo.autozone.com/znetcs/product-info/en/US/ste/MT1297/image/4/


this is a switch in the back of the compressor..  the system has to be empty to replace EITHER of these..

http://contentinfo.autozone.com/znetcs/product-info/en/US/ste/MT0674/image/4/

Switch - Pressure in compressor. Double pin black - replaces Single pin white - low pressure cut-off.     Compressor Mounted Switch - GM/Harrison - High Side Low Pressure Cut-Off (Black with Pigtail - Replaces Single Pin White and Light Blue Straight)

Switching Pressure:    45

there are several versions of this pressure switch listed..

http://contentinfo.autozone.com/znetcs/product-info/en/US/ste/MT0672/image/4/

2 pin switchA/C pressure in compressor switch. Radiator fan control. Compressor Mounted Switch - GM/Harrison - Cooling Fan (Grey)

Switching Pressure:    240


http://contentinfo.autozone.com/znetcs/product-info/en/US/ste/MT0447/image/4/


2 pin switchA/C pressure in compressor switch. High pressure cut-off.     Compressor Mounted Switch - GM/Harrison - High Pressure Cut-Off (Blue - Replaces Red, Tan & Dark Orange)

Switching Pressure:    430



this is one variation of the ac clutch relay..

with care.. one can remove the cover without damaging it.. this leaves you an exposed relay that you can manually operate.. with the tip of a screw driver to close the contacts..

http://contentinfo.autozone.com/znetcs/product-info/en/US/f11/35928/image/4/


this might be your AC system

http://parts.nalleygmc.com/showAssembly.aspx?ukey_assembly=400634&ukey_make=1024&ukey_model=14523&modelYear=1993&ukey_category=19447&ukey_driveLine=0&ukey_TrimLevel=0&ukey_modelRange=0&searchString=



here is the direct image link without part numbers
http://parts.nalleygmc.com/images/parts/gm/fullsize/9310201W09-006.JPG

i just don't have a proper wiring diagram for the AC system.. to know how its all hooked up...

in the 90 manual.. it shows a low pressure switch that cuts off clutch power before the relay..   so the relay could close.. but there still would NOT be any power to the contacts in the relay to send to the clutch coil..

my best advice.. pull the cover off the relay.. or find another one that you can open.. see if when you manually close the relay contacts if the clutch engages.. this is just a circuit test..  if not.. look at the low pressure switch..

[Mikej]

If there is power to the pressure is it going thru the switch. If not you don't have enough gas in it.

[34ford]

this might be your AC system

http://parts.nalleygmc.com/showAssembly.aspx?ukey_assembly=400634&ukey_make=1024&ukey_model=14523&modelYear=1993&ukey_category=19447&ukey_driveLine=0&ukey_TrimLevel=0&ukey_modelRange=0&searchString=


Yes wayne, this is my system.

the first pressure switch you show is what is similiar to mine. Mine has a 3 pin connector on it. It looks like 2 small blocks on the bottom and one stacked on top

         O
       O  O      the botton 2 are where I get a voltage reading. The top one jumped to either of the bottom ones yeilds 0 voltage reading.

[34ford]

Finally got around to working on the wife's car again. It was 83, new record high that was 33 degrees above normal for this time of year, so the ac needs to work again.

I now have 2 1/2 cans of freon in the system. I checked all the fuses and relays and circuit breakers and all are well.

I did also open up a relay and manually closed the contact while the car was running and nothing happened.

I did the jumper wire in the diagnostic plug in A & B and came up with a long flash and 2 short ones. When I jumped it the cooling fan comes on under the hood, thought that was strange. There are only 3 terminals in the plug that have contacts in them, A & B and one under A.

guess it's time to take it to someone smarter then me  :cry:

[wayne petty]

i don't have alldata or Ondemand to look up the AC wiring...

somebody might...

you can also look them up at

eautorepair.net

or

alldatadiy.com

both have short subscription times..

they will have the proper info for testing..  right out of the factory manual..


when i looked at the gm parts link.. it showed the sensor for just the 93 model... when i googled that part number.. it shows a much wider usage..

ACDelco Part No   15-72104
GM Part No   22599559
New ACDelco Part No   No
First Year   1987
Last Year   1994

if this is so.. perhaps my 1990 pontiac GP manual will show something..

[wayne petty]

this is from a 90 GP with a 3.1 V6..

[tomslik]

Finally got around to working on the wife's car again. It was 83, new record high that was 33 degrees above normal for this time of year, so the ac needs to work again.

I now have 2 1/2 cans of freon in the system. I checked all the fuses and relays and circuit breakers and all are well.

I did also open up a relay and manually closed the contact while the car was running and nothing happened.

I did the jumper wire in the diagnostic plug in A & B and came up with a long flash and 2 short ones. When I jumped it the cooling fan comes on under the hood, thought that was strange. There are only 3 terminals in the plug that have contacts in them, A & B and one under A.

guess it's time to take it to someone smarter then me  :cry:

i'm 500 miles west of ya;)....

[tomslik]

Finally got around to working on the wife's car again. It was 83, new record high that was 33 degrees above normal for this time of year, so the ac needs to work again.

I now have 2 1/2 cans of freon in the system. I checked all the fuses and relays and circuit breakers and all are well.

I did also open up a relay and manually closed the contact while the car was running and nothing happened.

I did the jumper wire in the diagnostic plug in A & B and came up with a long flash and 2 short ones. When I jumped it the cooling fan comes on under the hood, thought that was strange. There are only 3 terminals in the plug that have contacts in them, A & B and one under A.

guess it's time to take it to someone smarter then me  :cry:

i'm 500 miles west of ya;)....

i'd post a wiring diagram but at 3.30 in the morning, i ain't got the patience to resixe the stupid thing...pm me your email and i'll send it to ya...


here's what i'd do, grounded test light to the grn wire (at the compressor) and jump the relay (or manually operate it) and see if it lights up.
if so, the wiring is good to the comp. clutch.
next, hook the test light up to B+ (positive battery) and check the black wire, if it lights up, you'vr got ground,
if  both are good, the clutch is bad.
the diode is there for voltage spikes when the clutch turns on and off and no other reason...

[34ford]

Finally got around to working on the wife's car again. It was 83, new record high that was 33 degrees above normal for this time of year, so the ac needs to work again.

I now have 2 1/2 cans of freon in the system. I checked all the fuses and relays and circuit breakers and all are well.

I did also open up a relay and manually closed the contact while the car was running and nothing happened.

I did the jumper wire in the diagnostic plug in A & B and came up with a long flash and 2 short ones. When I jumped it the cooling fan comes on under the hood, thought that was strange. There are only 3 terminals in the plug that have contacts in them, A & B and one under A.

guess it's time to take it to someone smarter then me  :cry:

i'm 500 miles west of ya;)....

i'd post a wiring diagram but at 3.30 in the morning, i ain't got the patience to resixe the stupid thing...pm me your email and i'll send it to ya...


here's what i'd do, grounded test light to the grn wire (at the compressor) and jump the relay (or manually operate it) and see if it lights up.
if so, the wiring is good to the comp. clutch.
next, hook the test light up to B+ (positive battery) and check the black wire, if it lights up, you'vr got ground,
if  both are good, the clutch is bad.
the diode is there for voltage spikes when the clutch turns on and off and no other reason...

thanks, I will give that a try on sat.. Hate those late night when a person can't sleep
if you were closer it would be in your shop.

[34ford]

Did some more work on trying to find out what's up with the ac. These are not in the order I found them, just what I found.

Pulled the plug off the clutch and took a test light and it lights up touching each wire on the plug (the green and the black) that hooks to the clutch. this is with the ingition switch on and ac on cool without motor running. (tells me that they are both hot)

the 15 amp ign fuse on the fender fuse box was blown. This is what gives power to the relay for the clutch. (learned this from the diaghram from tomslik sent me)

when I put in a new fuse and turn on the ac without the cultch plugged in it blows the fuse. (this all runs thru the ecm so I assume that there is something a miss in there.)

forgot to try and energize the clutch with a pair of jumper wires.

So I'm thinking that I had a bad clutch and when I turned on the ac it blew the fuse and somehow caused a short in the ecm.

All I did to start with was remove the compressor lines unplug the clutch wire and replace the whole unit, put it all back together and this all started.

It did all work before I took it apart, it was just leaking bad around the seal and thought replacing the whole unit would be easier than just changing the clutch since you have to pull the whole unit out to change the clutch cause there is only about 1" in front of the clutch to the inner fender and frame.

So my question if I pull out the ecm is there placec that can test the circuits in them?

thanks

bob[/b]

[34ford]

Did some more work on trying to find out what's up with the ac. These are not in the order I found them, just what I found.

Pulled the plug off the clutch and took a test light and it lights up touching each wire on the plug (the green and the black) that hooks to the clutch. this is with the ingition switch on and ac on cool without motor running. (tells me that they are both hot)

the 15 amp ign fuse on the fender fuse box was blown. This is what gives power to the relay for the clutch. (learned this from the diaghram from tomslik sent me)

when I put in a new fuse and turn on the ac without the cultch plugged in it blows the fuse. (this all runs thru the ecm so I assume that there is something a miss in there.)

forgot to try and energize the clutch with a pair of jumper wires.

So I'm thinking that I had a bad clutch and when I turned on the ac it blew the fuse and somehow caused a short in the ecm.

All I did to start with was remove the compressor lines unplug the clutch wire and replace the whole unit, put it all back together and this all started.

It did all work before I took it apart, it was just leaking bad around the seal and thought replacing the whole unit would be easier than just changing the clutch since you have to pull the whole unit out to change the clutch cause there is only about 1" in front of the clutch to the inner fender and frame.

So my question if I pull out the ecm is there placec that can test the circuits in them?

thanks

bob[/b]

One other detail late this afternoon. I hooked up the clutch to 12v and it does work, so that rules out the clutch now.

[enjenjo]

Sounds to me like the compressor clutch diode is bad. recheck those two leads with the ac off, and with the ignition off. Also check the resistance on the clutch. And check that one of the wires actually has a ground. If the compressor diode is bad it will send the relay power right to ground, blowing the fuse.

[34ford]

Sounds to me like the compressor clutch diode is bad. recheck those two leads with the ac off, and with the ignition off. Also check the resistance on the clutch. And check that one of the wires actually has a ground. If the compressor diode is bad it will send the relay power right to ground, blowing the fuse.

I have the compressor unplugged, completely out of the electrial loop, and it still blows the fuse.

Is there anyway they can check circuit in the ecm??