A/C Blows
Thread Starter
Joined: Nov 2006
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A/C Blows
I have a 99 Dakota with the 5.2 and for some reason the AC compressor will all of a sudden go out and then come back on at the most random time. Its most annoying during the summer when its 110 degrees out. The system has plenty of freon and I changed the relay. Any ideas?
Champion
Joined: Dec 2003
Posts: 4,119
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From: Sycamore, Illinois (displaced to Arkansas)
RE: A/C Blows
It could be the low pressure switch is either faulty or there is just too low of a pressure on the system. It could also be the high pressure switch is either faulty or sensing too high a pressure on the system.
To test if the low pressure switch is causing the problem, gain access to the low pressure switch (located on top of the A/C accumulator, which is located on the passenger side of the engine compartment, on the firewall). Disconnect the electrical connector and put a jumper wire between the two connector terminals.
Also, ensure the actual low pressure switch is securly fastend to the accumulator. If jumping across the terminals gets rid of the problem, you either have a bad switch, or the system isn't producing enough pressure.
If that doesn't solve your problem, it could be the high-pressure switch (also called the A/C pressure transducer). This is usually located in the right front of the engine compartment of the Gen 2 Dakotas. However, it can be located on any high-pressure line (sometimes on the output side of the compressor). The only thing I can really tell you about this is that the violet/white wire provides 5 volts from the computer, the dark blue wire provides a reading back to the computer, and the black/light blue wire provides a ground.
My thinking would be if you place a jumper wire acorss the violet/white (voltage to the switch) and dark blue (reading back to computer) connections, and the A/C cuts out, than 5volts to the computer tells it to shut off (or, if when you disconnect the switch and the A/C doesn't work, than you know lack of voltage tells the computer there is too high of pressure).
You also need to know that some cycling of the A/C is normal, and the cooler it is out, the harder it will be to ops check it. And, if you have a pressure problem, you need to get it fixed, because you could ruin the compressor or other components if you run them with either too much or too little pressure.
To test if the low pressure switch is causing the problem, gain access to the low pressure switch (located on top of the A/C accumulator, which is located on the passenger side of the engine compartment, on the firewall). Disconnect the electrical connector and put a jumper wire between the two connector terminals.
Also, ensure the actual low pressure switch is securly fastend to the accumulator. If jumping across the terminals gets rid of the problem, you either have a bad switch, or the system isn't producing enough pressure.
If that doesn't solve your problem, it could be the high-pressure switch (also called the A/C pressure transducer). This is usually located in the right front of the engine compartment of the Gen 2 Dakotas. However, it can be located on any high-pressure line (sometimes on the output side of the compressor). The only thing I can really tell you about this is that the violet/white wire provides 5 volts from the computer, the dark blue wire provides a reading back to the computer, and the black/light blue wire provides a ground.
My thinking would be if you place a jumper wire acorss the violet/white (voltage to the switch) and dark blue (reading back to computer) connections, and the A/C cuts out, than 5volts to the computer tells it to shut off (or, if when you disconnect the switch and the A/C doesn't work, than you know lack of voltage tells the computer there is too high of pressure).
You also need to know that some cycling of the A/C is normal, and the cooler it is out, the harder it will be to ops check it. And, if you have a pressure problem, you need to get it fixed, because you could ruin the compressor or other components if you run them with either too much or too little pressure.
Professional
Joined: Aug 2004
Posts: 191
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From:
RE: A/C Blows
Mine constantly cycles too. Even if I have it set to defrost, or to the floor, or anything except "off" as I stated in my other post. I tried to recharge it this summer and that seemed to help. When I started to add the R-134a the clutch engaged and ran the whole time, and would only engage when I turned the **** to one of the two a/c settings. Now it's back to the same constant cycling of one for a few seconds and then off, then on for a couple more seconds. I'll have to test the low pressure switch too as mentioned.