Dodge Repair/2011 Caravan A\C
QUESTION: Hi : I've had a problem with a leak in the AC but replaced the line and it seems to hold a vacuum. The Haynes Repair manual says that you most likely have to keep the compressor running by removing the connector from the pressure switch and bridging it with a paper clip - but doesn't show any photos or diagrams. Could you explain that better and of course diagrams would help.
ANSWER: Hi Steve,
My most recent manual is an '09 which I can check for a pressure switch diagram. But it sounds to me like you would locate the coolant pressure switch of the AC, and then remove the 2 pin connector plug from that, and simply jump a wire (paper clip) between the 2 sockets of the switch connector plug. That would simulate a situation where the compressor would be given the go ahead to be operated via closing the clutch on the compressor just as if the pressure in the system were within the proper range which is the normal purpose of the pressure switch. I don't understand what the Haynes is trying to do, but this is how you can make sure the compressor will operate all the time even if the pressure is not in the acceptable range. I would not try to leave it this way but only do this as part of a repair job.
I find that the pressure switch is also called the pressure transducer and it is located in the right rear of the engine compartment on to of a cylindrical container called the receiver/drier. The instruction from the Haynes seems unusual in the transducer has a 3-wire plug(a dark green/dark blue grounded wire, a pink/yellow 5 volt supply wire, and a light blue/ brown wire that is the variable signal wire that reports the pressure in the system and can vary between 0 and 5 volts. The acceptable voltage for operation is .45 to 4.5 volts and I can't see what shorting the signal wire to the 5v wire will accomplish. The other way to make the compressor run would be to jump 12v to the wire on pin 1 of the clutch itself (which has a 2-wire plug and pin 1 has a dark blue/yellow wire on its plug) which would simulate the closing of the clutch's relay if that is what is wanted.
So figure out what Haynes wants you to accomplish.
---------- FOLLOW-UP ----------
QUESTION: Thanks I'm glad I'm not the only one that doesn't understand the Haynes instructions. I think the intent was to use the compressor to load the system. Your solution sounds the most appropriate - can you point me to a diagram to be sure I'm using the right pressure switch?
Perhaps you misunderstood. My point was that the refrigerant pressure switch is not likely to be seen as closed "closed" by using a paperclip across its plug terminals because it won't activate the compressor unless the voltage applied to it is between .45 and 4.5v, not 0 or 5v which is all you can get with a paperclip 'short'.
So I suggest going to the compressor proper and jump 12v from the battery to pin 1 of its socket, and ground pin 2 of its socket with a similar jumper wire. You can look at the plug once you have removed it to identify which is pin 1 and which is pin 2 of the socket as that is usually shown directly on the plug. I don't have a diagram that shows the details of the compressor electrical plug/socket.