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Followup To
Question -
Good morning Roland,
I have a similar problem as A/C not working covered in your forum but the problem i have is that the A/C light comes on but does not pull in the clutch. The relay is OK and the clutch pulls in if i manually work the relay. I pulled the control console off and the A/C has not worked since. The car is what we in Australia call a chrysler Grand voyager similar to your town and country I'm thinkking 2000 model.
look forward to your reply, regards Mark Howlett
Answer -
Hi Mark,
Thanks for reminding me there is another hemisphere and that heat in not the only concern this time of year in your half of the world.
I am working from the wiring diagrams in the Haynes manual that covers thru '99 which is probably also relevant for your 2000 year model in Australia.
When you say that the clutch will work when you manually operate the relay, I am not certain if you are doing this by artificially applying 12v to the white/black wire of the actuator coil, or grounding the dark blue/orange wire of that coil, or jumping 12v to the dark blue/black wire that goes to the clutch. Have you verified that you have 12v on the white/black in run and start position of the ignition switch, and verified that you have 12v on one relay socket pin that gets its voltage from a 15 amp fuse (in '98 was fuse 11 in the underhood (underbonnet?) powerdistribution center)?
If those two supply voltages are present, and you can make the clutch work "manually" from the relay by electrically actuating the relay, then the power to run the relay, and wire to the clutch, and the relay itself are o.k.
The issue then turns to the dark blue/orange wire from the relay to the powertrain control module (engine controller) to see if it is patent. In '93, all the controllers had 60- pin plugs, and the dark blue/orange wire was found on pin 34 of the plugs, so if that is still the case in the 2000 model that is where you could check that wire.
The a/c 'on' signal from the control console is carried on a dark green wire to the engine contoller but I can't ID the pin for you because the wiring design changed after '93 which is the latest true Chrysler-published shop manual that I have. But that dark green wire needs to be verified of course. And then you might put a volt-ohm meter on it and see if you can detect a change in state of the voltage on that wire depending upon whether you have the a/c switch off or on.
So somewhere in that chain of wires you will find the reason that the clutch is not being activated by the relay.
Let me know if you have further questions, and maybe tell me which engine you have, and whether the controller has a single 60-pin or two 40-pin connectors. I do have a trouble shooting manual for 2001 that gives me the pin assignments for the latter used with the 2.7, 3.2 and 3.5L engines.
By the way, another reason why you may not be getting any clutch response is that you are too low on refrigerant in the system rather than there being an electrical problem. There is a pressure sensor that also feeds a signal the the powertrain controller that has to indicate sufficient refrigerant is present or it disallows the use of the compressor to protect it from damage by being operated with insufficient lubrication that is provided by the refrigerant. So this may be the only reason you are having a problem! I don't know whether if that were the case the light would not come 'on' as you describe, but it is worthy of consideration as the cause.
Roland
Afternoon Roland,
I went through your list of suggestions as follows:
relay and power to the clutch are OK as per your suggestions, I lifted the top off the relay and noticed on turning on power to start the car the relay pulls in briefly then off again (computer function check?) the controller has 2 40 pin connectors (no signs of corrosion) and the engine is a 3.3 litre petrol.
I checked voltages on the connector that joins onto the a/c board but could not detect any voltages changing state with the A/C switch although black/white, Brown/pink, white/red and dark green/blue had 12 volts + with the engine running. the others had voltages ranging from 0VDC to 5VDC but no change in either state of the A/C switch. the green wire had 5 volts to ground on it in either state of the A/C switch. with regards to the pressure switch I checked this out and shorted it out in the plug with no change except in one bridge it stopped the engine. The only thing I haven't tried is to make sure that between brown/pink and black/light green there is 12 volts just to confirm that the black/light green wire is tied down to the frame. (on the A/c circuit board)
the wires that are on the grey rail of the plug above and volts are as follows:
white/red, 13.6v
dk green/blue, 13.6v
green,5v
red/white,0.8v
yellow,5v
black white,13.6v
dk blue/orange,1.05v
red/blue,4.7v
brown/pink. 13.6
on the yellow rail
orange 0v
blue/white 0v
blue 0
purple brown 2.5v
blue/pink 0v
white/black 2.5v
blue/red 0v
green/yellow 0v
grey/blue 0v
blue/black 0v
black/green 0v
hope I've given you enough to work with,look forward to your reply,
regards Mark Howlett
AnswerHi Mark,
I am a little confused about whether you are Mark Howlett or a different Mark, and which part other than the first paragraph is new and which is old. I thought you were a new Mark ? questioner but now I am not sure. The bottom line is that for the clutch relay to be energized a light green/dark blue wire on the relay that comes from the powertrain controller has to be grounded by the controller. The controller will only ground that wire if two things are true: The A/C switch is activated by the control panel (I am not sure but I suspect it has to have voltage of some sort on it in the "on" position) and that is carried from the control panel to the powertrain controller on a dark green wire,
AND
there is sufficient refrigerant in the system to satisfy the pressure transducer which is a three wire device in the refrigerant line near the compressor which also goes to the powertrain controller (black/light blue is ground, violet white is 5 volt sensor supply, and dark blue is the sensor signal that tells the powertrain controller what the pressure is (a variable voltage between 0 and 5, but I don't know what the trip point is for it to be satisfied).
I may have the wiring of the plugs for the powertrain controller in another manual, but I need to know which engine is in your van and the number of pins on the plug(s) to the powertrain controller
I am not sure if your problem has to do with having "pulled the control console off" but if you then plugged it back in correctly I don't think that move would be the cause of your problem. Have you checked for refrigerant level to be sufficient (pressure gauge reading at an A/C service shop)? Other than that and checking the voltages directly relevant that I listed above, I can't think of too much else to suggest. If you can clarify things about my initial confusion it might be helpful to me, but all the color coded voltages are somewhat confusing because the Haynes doesn't show the two 'rails' as distinct, and which color is primary and which is trace is relevant but you can't always be sure of that if you don't have a rail differentiation drawing (which I don't).
So let me know what is going on here.
Roland
