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I have a 1997 Isuzu Rodeo / Honda Passport V6.

The AC will turn on and work indefinitely when it's not very hot outside (70's or lower).

When it's more like the 80's and higher, the AC will ALWAYS work for about 10 minutes, then I notice the AC condenser fan will turn off and stay off (the little fan in the front part of my grill). At this point, the cool air coming out of the vent starts to warm up. The air is warm after about 30 seconds of running, after the AC condenser fan turns off. So no more cool air. However, if I'm driving more than 45 miles an hour, the AC will work, most likely because there is air to cool the car down. The condenser fan is mostly likely still off. I can hear the AC compressor click on and off at all times. I believe my condenser fan is suppose to run when I'm idle to cool off the AC components (radiator?). I'm wondering what would cause the fan to work the first 10 minutes, then turn off?
Does the fan have an internal over-heating mechanism? Does the fan have special wiring components that don't work when hot? Should I just buy a new fan and install it, or is that a waste of time? The engine temperature sensor is VERY difficult to reach in my car so I don't plan to replace this unless it IS the problem.

I don't have a refrigerant leak. My pressures for the AC system is working perfectly (tested by a mechanic). I tried replacing/swapping the relays next to the car battery.

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  • When the fan stops, are you able to turn it by hand (with the engine off obviously)? If not, the fan bearings may be heating up and seizing.
    – CharlieRB
    Jun 15, 2017 at 19:46
  • Yes, very good comment. I'll try to manually move it when it's cool and compare it to when it's hot.
    – Andy
    Jun 16, 2017 at 16:45

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Yes, no, I don't know. There are a whole lot of controls on engine cooling fans. I'm assuming this vehicle has just an electric cooling fan and not an engine driven fan as well.

Step number one is for you to obtain the technical information on how your vehicle is supposed to work. This could be as easy as purchasing a Haynes or Chilton repair manual (~ $30)

As you've already identified poor condenser cooling = shutdown of your Air Conditioning (A/C) system. That's to protect you and your car from damage.

Step 2. After you read the book I'm guessing you have some sort of Pulse Width Modulation (PWM) device that controls the cooling fan, generally based on control signals from the engine control computer. Obviously you are going to want to ensure that there are no check engine codes. Possible fan motor needs work or PWM controller needs work or signal from computer is off because of some sensor somewhere. The book should have a step by step troubleshooting procedure.

Step 3. Is engine coolant system working correctly? No leaks? Overflow system working correctly? Radiator cap seals correctly in both directions (vacuum return plus 13-16 psi relief?)

Step 4 is to inspect the entire cooling system for airflow? Any blockage up front? Are all the seals between the condenser and radiator present and in good working order?

Let's us know what you find.

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  • Yes, I'll keep this post updated. The radiator cap and coolant fluid was replaced last year. The temperature gauge is stable and the thermostat was also replaced last year. The electrical fan that turns off has some kind of clutch so it can easily turn on and off.
    – Andy
    Jun 16, 2017 at 4:09
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It appears as though, I may have been mistaken about the compressor running and the AC condenser fan being turned off. I thought I could hear the compressor continue running but it looks like it turned off as well. In other words, the AC fan, compressor, AC system turned off when I was driving at speeds from 1 - 45 mph with lots of stop and go (traffic lights).

I tried replacing the AC condenser fan with another used one but that didn't work. So I had to go to a dealership to have it looked at. The mechanic tested the system for leaks, signals, pressure, and everything looked good. The mechanic couldn't get it to fail while driving the car, but I could make it fail. Which made me realize, when I drive a little faster than most people, the rpm (acceleration) might be affecting the AC system. So the mechanic checked it out when I made the AC failed. He stated that the clutch system on the compressor was not engaging. The clutch would fall to far back and not re-engage appropriately. That the AC compressor and clutch would have to be replaced and the relay is recommended as well. After all this troubleshooting, it started to make sense. He stated that the acceleration and rpm's affects how and when the clutch engages on the compressor. I also noticed, when I drove at a more constant or slower rate, the AC would stay on longer. Also, when I never took it out of park, the AC also stayed on longer. Right now, I'll drive it as is and then fix it if it fails completely. I'd like to keep my car a few years longer because the rocker arms and cam shafts have been replaced and it's a really good car for towing trailers. Thanks for those who posted with advice.

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  • I replaced the compressor part with a used one. It looks like it was the clutch on the compressor. The compressor has a built in clutch that uses a magnet, I believe, to activate and deactivate the compressor rotation. For some reason, the compressor worked for short periods of time and worked less during really hot weather. But once it got replaced, the AC temperature stays consistent and cold. It also stays on during acceleration unlike the old compressor.
    – Andy
    Jul 23, 2017 at 5:04

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