Engine hotter when air conditioner on at idle

Tiny
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  • 2006 CHRYSLER PT CRUISER
  • 2.4L
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 100,000 MILES
When I turn the air conditioner fan to maximum and car at idle the engine runs hotter. The temperature gauge goes up. When I drive the car and air conditioner on the gauge goes down where it suppose to be. When air conditioner is off at idle or driving the temperature is normal.

the car has one fan for air conditioner and radiator. When I turn the air conditioner on the fan runs. When engine get hot the fan runs.

what the maximum safe engine temperature?
what could be causing the little overheating?
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Saturday, July 23rd, 2016 AT 6:55 PM

23 Replies

Tiny
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  • EXPERT
The blower speed has no bearing on temperature but the air conditioner compressor adds load to the engine which can increase the temperature. This could mean that the radiator has marginal cooling capacity or even that the water pump is not circulating sufficiently but that would be rare. What is even more likely though is that the cooling fan has lost high speed as this is a two speed fan system.
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Sunday, July 24th, 2016 AT 5:27 AM
Tiny
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Yes I never heard the fan goes to the high speed. There is only one speed. When I turn the air conditioner on and the engine is cold the speed is the same when the radiator fan goes on. Is the first speed works with twelve volts and the second speed works with twenty four?
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Sunday, July 24th, 2016 AT 9:07 PM
Tiny
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What I want to know is; does the PCM send a twelve volt supply to the low side brushes for low speed and twelve vol to the low and high side brushes for high speed?
Or, does it send twelve volts to the low side brushes for low speed and twelve volts to the high side brushes for high speed?
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Monday, July 25th, 2016 AT 12:42 AM
Tiny
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The fan itself has two different internal circuits. One of them has a resister built into it so you have to test the fan at both inputs.

https://www.2carpros.com/images/external/164049153.jpg
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Monday, July 25th, 2016 AT 4:39 AM
Tiny
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So if a jump one of the relay it should run low or high and if I jump the other relay it should also runs low or high. Is it correct?
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Monday, July 25th, 2016 AT 8:05 AM
Tiny
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No, you cannot jump the relays. They are internal to the fuse box and not accessible or serviceable. If they are bad you have to change the whole fuse box which is called the TIPM (Totally integrated Power Module) You can apply power to the individual wire inputs at the fan. The diagram gives you the wire colors.
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Monday, July 25th, 2016 AT 9:51 AM
Tiny
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The relays are at the front of the engine on the cooling fan. There are no visible relays in the tipm. They did that for 2006 and up. I did jump them before because I had problem with one of them. When the ac was on the fan did not engage and I had to replace the relay.
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Monday, July 25th, 2016 AT 9:03 PM
Tiny
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This is a link from a youtube video
https://www.youtube.com/watch?v=MNW7cjlEObE
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Monday, July 25th, 2016 AT 9:05 PM
Tiny
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According to the factory wiring diagram for your vehicle, they are in the TIPM. That is what I go by, not a youtube video for a different year car that some guy made. As I stated, they wouldn't be visible anyway.

If the diagram is wrong and the relays are external, that's fine but you can't rely on the fuses to them being good so jumping the relay won't work unless you have verified that.
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Tuesday, July 26th, 2016 AT 4:06 AM
Tiny
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Yes I have verified there are two relays for the fan on the fan itself. I bypassed the relay in the past I jumped the two thick red wires and the fan came on
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Tuesday, July 26th, 2016 AT 7:34 AM
Tiny
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You need to be very careful doing that. If you happen to jump the wrong 2 wires, you will trash your PCM in a heartbeat.
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Tuesday, July 26th, 2016 AT 7:36 AM
Tiny
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Yes sir thank you
. So if I jump one of them the fan should run on low speed and when I jump the other it should run on high speed right?
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Tuesday, July 26th, 2016 AT 8:12 AM
Tiny
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Assuming the relay still has power supply, yes.
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Tuesday, July 26th, 2016 AT 8:20 AM
Tiny
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When I jumped both relays the fan turned on with the same speed. I did not notice difference between both of them. When the engine was cold I turned on the ac the fan turned on. When I removed the relay it stopped turning. I put back the ac relay and turned off the ac after I let the car idle with ac off the fan came on. So I guess both relays are good and both circuit fan1 and fan 2 works. The question is why the fan has only one speed?
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Sunday, August 7th, 2016 AT 2:26 PM
Tiny
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I went to a 2005 to see a system with 2 external relays. The speeds are built into the motor with a resister on one of the feeds inside the motor. The yellow wire is high speed and the dark green is low speed.
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Sunday, August 7th, 2016 AT 2:34 PM
Tiny
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I have another question. The p0882 code came back yesterday. I thought I fixed I was a loose wire in the tipm the one coming from the computer to the tipm I checked it today ( I wiggled it )it was good. However when I wiggled the pcm harness everything went crazy the antitheft light was flashing. The PRND letters had squares arround them. And my scantool was not unable to communicate with the computer.

My question is was is safe to wiggle the computer connector. And why everything went crazy?
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Sunday, August 7th, 2016 AT 3:21 PM
Tiny
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You found the source of a problem somewhere in that harness. I would unplug it at the computer and see if there is any corrosion at the plug
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Sunday, August 7th, 2016 AT 3:26 PM
Tiny
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So was is safe that I wiggle the computer connector?

( I do not want to damage the computer). I unplugged the negative battery and the connector and plug it back and the crazy things went away

so I need to look for green staff on the harness connector right?
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Sunday, August 7th, 2016 AT 3:44 PM
Tiny
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Look real close. It won't be real obvious. Just unplugging it and plugging it back in may resolve it.
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Sunday, August 7th, 2016 AT 3:46 PM
Tiny
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Do I need to disconnect the battery before I unplug the computer connector?
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Sunday, August 7th, 2016 AT 3:53 PM

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