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Old 12-27-2016, 01:25 PM   #1
mikeshaw
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01 Chevy Venture Cooling Fans & AC Not Working

(Update: The problem described here has turned out to be a leak in the condenser on the bottom, passenger side where the attachment bracket is. Links to pictures and descriptions below. It's a large leak which in this case caused the AC to go from nice and cold to warm air in probably just a day or so. The loss of refrigerant and low pressure causes the compressor clutch to stop engaging. The fans also do not turn on as they normally do when the ac system reaches a certain pressure. The leak is easily noticed by simply looking at the bottom corner passenger side of the condenser, at the front of the car in front of the radiator. You can see a very large oil stain on the condenser. )

2001 Chevy Venture

Does anyone out there have any further insight on how to fix this ?

Problem: Cooling fans & AC compressor not turning when AC is on full blast, & there's no cold air. Though cooling fans do at least turn on and cool properly when temp gauge reaches normal range.

1. first noticed a problem when temp gauge was running higher than usual. Found that passenger side radiator fan was not turning on, even with AC cranked. Found there was 14 volts at the fan connector. I replaced the fan motor. The fans then worked and were running properly. They ran when the AC was turned on and when the temp gauge reached the normal range to cool the engine they turned on. So it looked like all was good. But I had noticed while replacing the fan motor that the 4 pin connector to the 2 fans was burned on the side of the fan which had failed.

3. After a few days of driving i then noticed the AC is not blowing cold. Fuses and relays all looked good. I noticed the ac compressor was not turning. There was very low voltage at the connector. (Though I could not properly seat the multimeter probes into the connector as they were too big, so I'm not 100% certain about the reading)

4. I also notice that the cooling fans are not turning on either when the AC is on. They were running with AC on after I had installed the fan motor, at least for some time. And again, they fortunately do turn on when the temp gauge reaches normal range.

I believe it could be a bad ground connection between the compressor and cooling fans. The AC button inside the vehicle normally powers up the cooling fans and engages the AC compressor clutch. Looking at a wiring diagram I have attached here both the cooling fans and ac compressor clutch both have a black wire with a connection that says "S105, ENGINE HARN 4CM FROM ENGINE FAN WIRING HARN BREAKOUT". I am assuming this has something to do with the connection that powers them both when you press the AC button. Apparently there is short in this connection it seems.

Also, an ongoing issue for a couple years which could be related has been with code P0128. What happens every few thousand miles is the check engine light will come on & at the same time the temp gauge stays flat, and the cooling fans will run continuously. I found that by either removing & replacing the fan relays, or by clearing the code, the problem temporarily resolves and all goes back to normal for a few thousand more miles.

Presently I have codes P0128 as well as
P0141 - (HO2S-12 Bank 1 sensor 2) / Heater circuit malfunction
P0440 - EVAP System No Flow During Purge

The P0141 and P0440 are codes which I've never had before, but they don't seem related to this issue. P0141 (O2 sensor related), P0440 (gas cap, fuel related)
Attached Images
File Type: jpg wiring diagram chevy venture.jpg (315.2 KB, 3 views)

Last edited by mikeshaw; 01-22-2017 at 08:00 PM.
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