A/C question and problem
Thread Starter
Drifting
Joined: Apr 2004
Posts: 1,889
Likes: 0
From: ottawa ontario
A/C question and problem
Hey Guys, my AC is screwed up. My outside temp sensor does not read correctly. Someone told me to upplug it and it would default to 56F, but it didn't. I know the AC will not work unless it is 5f or hotter..The AC light will flash then stay off and other timesdit stays on so i know the AC works..Is there any way to fool the temp sensor? When i unpluged the outside temp sensor the temp didn't change on my display. Help. :cheers:
Drifting
Joined: May 2000
Posts: 1,917
Likes: 3
From: Southern NH
Re: A/C question and problem (mitymikec)
Mike:
The sensor is basically a thermistor that changes it's resistance value according to temperature. The colder it is, the lower the resistance, and the warmer it is the higher the resistance.
If you unplug the sensor, the open circuit is equivalent to a high resistance. The system should detect this "out of range High" reading and default it as I mentioned. If you are not seeing any change, the only other things I can think of are:
- the plug is corroded and still shorting the leads, which results in a low resistance.
- the AC head unit is not reading the sensor properly. There might be DIC codes.
Hope this helps.
The sensor is basically a thermistor that changes it's resistance value according to temperature. The colder it is, the lower the resistance, and the warmer it is the higher the resistance.
If you unplug the sensor, the open circuit is equivalent to a high resistance. The system should detect this "out of range High" reading and default it as I mentioned. If you are not seeing any change, the only other things I can think of are:
- the plug is corroded and still shorting the leads, which results in a low resistance.
- the AC head unit is not reading the sensor properly. There might be DIC codes.
Hope this helps.
Thread Starter
Drifting
Joined: Apr 2004
Posts: 1,889
Likes: 0
From: ottawa ontario
Re: A/C question and problem (JC in XTC5)
Thanks for the info. i unplugged it again and drove for a bit and the sensor went to a default setting of 60f. Would that mean that the sensor under my bumper is the defective piece? or can it be something else?Mike
Drifting
Joined: May 2000
Posts: 1,917
Likes: 3
From: Southern NH
Re: A/C question and problem (mitymikec)
It sounds like you need to do a more thorough inspection of the sensor and it's connector. Leave it disconnected for a few days to make sure the reading remains at the default level. If it does, then we know the problem is not with the AC unit, but either:
- the sensor is bad (only about $15 to replace)
- the connector is corroded and causing short circuit (common problem).
If the reading does change, then the problem MAY be with the head unit, but could still be the corroded connector.
If you can get access to the sensor connection (i.e. put the front on ramps and remove panel under nose of car), you should check the connector for corrosion, etc. If that's bad, then it needs to be replaced.
To be safe, you may want to change both the sensor and connector, coat the new connections with anti corrosive grease (or WD-40 workswell) to prevent future problems.
- the sensor is bad (only about $15 to replace)
- the connector is corroded and causing short circuit (common problem).
If the reading does change, then the problem MAY be with the head unit, but could still be the corroded connector.
If you can get access to the sensor connection (i.e. put the front on ramps and remove panel under nose of car), you should check the connector for corrosion, etc. If that's bad, then it needs to be replaced.
To be safe, you may want to change both the sensor and connector, coat the new connections with anti corrosive grease (or WD-40 workswell) to prevent future problems.
