Callibrate Overhead Thermometer
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New User
Joined: Oct 2003
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Callibrate Overhead Thermometer
Hi
I have a 2002 F150 and I really like my truck. The only problem I have is the thermometer in the overhead console is 2 degrees high all the time. I have verified this with other thermometers. Is there any way to recallibrate the thermometer?
Thanks
I have a 2002 F150 and I really like my truck. The only problem I have is the thermometer in the overhead console is 2 degrees high all the time. I have verified this with other thermometers. Is there any way to recallibrate the thermometer?
Thanks
Posting Guru
Joined: Jun 2002
Posts: 1,146
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From: Colorado
I can't offer a procedure to calibrate your thermometer, but I will offer this.....
Any digital reading device has a minimum uncertainty of +/- 1 count on the display, plus any other uncertainties with the measurement system. This means at the VERY best, you can expect your thermometer to read +/- 1 degree ( assuming the resolution is 1 degree). An error of 2 degrees with any low cost themometer is not unexpected. I have found throughout the years people expect any digital reading device to be absolutely correct. Unfortunately, this is not the case.
I worked in precision measurement for over 20 years, and yes, mine is off as well, and if I could calibrate it, I would too. If I find a way, I will post it here.
Any digital reading device has a minimum uncertainty of +/- 1 count on the display, plus any other uncertainties with the measurement system. This means at the VERY best, you can expect your thermometer to read +/- 1 degree ( assuming the resolution is 1 degree). An error of 2 degrees with any low cost themometer is not unexpected. I have found throughout the years people expect any digital reading device to be absolutely correct. Unfortunately, this is not the case.
I worked in precision measurement for over 20 years, and yes, mine is off as well, and if I could calibrate it, I would too. If I find a way, I will post it here.
Hotshot
Joined: Aug 2002
Posts: 12,679
Likes: 15
From: BC, Canada
I just took a look in the shop manual and it doesn't show any way to calibrate the thermometer.
2 degrees is probably within factory tolerance, even if it isnt right.
I suppose you could swap a temperature sensor from another truck and see if it's any better but it might be hard to find another truck to do that with. Perhaps your dealer could try that?
2 degrees is probably within factory tolerance, even if it isnt right.
I suppose you could swap a temperature sensor from another truck and see if it's any better but it might be hard to find another truck to do that with. Perhaps your dealer could try that?
New User
Joined: Sep 2003
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Where do you take the temperature reading with the other thermometers? Unless it is EXACTLY in the same place the sensor is for the other thermometer, it is like comparing apples and oranges. 2 degrees is not a whole awful lot, if it is in F. If it was C, then 2 degrees would be a fair error. Though, you would not believe the number of times I have come out to my truck and the temperature has been 34 C, only to drive 2 minutes, and have it show 14 C 
Posting Guru
Joined: May 2002
Posts: 1,673
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From: Chicago Area
I think the sensor is in front of the radiator so that normal air flow provides an accurate sample. But if you've been sitting still it may be affected by engine heat or other factors. Mine seems to be real accurate when driving.
I think the only way to "calibrate" them is to pick and choose sensors. Don't know for sure what type sensor they use, but if it's a thermister, you could add a variable resistor in series. Maybe you could read the resistance and see how it changes with temperature and add or subtract (parallel resistance).
It'd be a lot of work even for someone who knew what he was doing, unless you could find the guy who knows how it was designed!
I think the only way to "calibrate" them is to pick and choose sensors. Don't know for sure what type sensor they use, but if it's a thermister, you could add a variable resistor in series. Maybe you could read the resistance and see how it changes with temperature and add or subtract (parallel resistance).
It'd be a lot of work even for someone who knew what he was doing, unless you could find the guy who knows how it was designed!
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Logistics Pro
Joined: Mar 2002
Posts: 3,881
Likes: 84
From: Wake Forest, NC
My boss and I have played this game. We both have thermometers in our trucks (Ford and Chevy) we can both go out to our trucks, have really off readings, move them a little, get a more believeable reading and then sit next to each other and have readings that are 2 degress off. So who is right? I use the thermometer to get a general idea of whats going on outside. 2 degrees out side isn't really going to make that big of a difference. And since its on the truck, there are probably going to be heat sources that can raise it.
There is no easy way to calibrate it though.
There is no easy way to calibrate it though.
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More Turbo
Joined: Dec 2003
Posts: 660
Likes: 62
From: Southeast Kansas
This may be a "stupid idea", and it may not make a difference, but what if you follow the instructions for re-calibrating the compass?!?!? Since they are normally in the same unit.
Probably won't work, but..........
I've also noticed, that the metal signs at a bank, or something does NOT always agree with my truck. Likewise, with various radio stations.
Occassionally, my temp., will agree with a radio station, bank sign.
IMHO, accepting a 1-2 degree difference is CHEAPER than the cost of the labor/parts.
(My point is, without sounding like a smartazz, is there is no-one/no place that is "the standard" for "the" exact temp.)
Thanx,
Probably won't work, but..........
I've also noticed, that the metal signs at a bank, or something does NOT always agree with my truck. Likewise, with various radio stations.
Occassionally, my temp., will agree with a radio station, bank sign.
IMHO, accepting a 1-2 degree difference is CHEAPER than the cost of the labor/parts.
(My point is, without sounding like a smartazz, is there is no-one/no place that is "the standard" for "the" exact temp.)
Thanx,
Senior User
Joined: May 2003
Posts: 285
Likes: 0
From: Maryland
It seems to me that most of our home thermometers and electronic temp devices are not going to be 100% accurate.
I remember going into a hardware store in search of an old fashioned thermometer (the kind where the glass tube is stapled to the plastic housing) and each of the thermometers showed a slightly diffferent temp -- generally within 3 degrees of each other. I choose one that had the most other thermometers that read the same temp.
We do expect a lot of our devices.
But the temperture devices even if 100% accurate can be influenced by location (distance from the ground or closeness to a structure etc.). In the greater Balto/DC area where I live if one is near the water, the temp can be higher in the winter or cooler in the summer. And closer to the city and the temps generally go up. Someone who's house is next to a stream and in a valley will have a different temp than the person living a mile away on a rise.
When I was a private pilot, the general rule we learned is that on a "normal" day, the temp drops 3 degrees for each 1,000 feet of elevation.
I use the temp guage in my truck to amuse myself and know in general what the weather is like on the outside (good to know on a long trip) but I would not use the gauge to do any scientific experiments.
Chip
I remember going into a hardware store in search of an old fashioned thermometer (the kind where the glass tube is stapled to the plastic housing) and each of the thermometers showed a slightly diffferent temp -- generally within 3 degrees of each other. I choose one that had the most other thermometers that read the same temp.
We do expect a lot of our devices.
But the temperture devices even if 100% accurate can be influenced by location (distance from the ground or closeness to a structure etc.). In the greater Balto/DC area where I live if one is near the water, the temp can be higher in the winter or cooler in the summer. And closer to the city and the temps generally go up. Someone who's house is next to a stream and in a valley will have a different temp than the person living a mile away on a rise.
When I was a private pilot, the general rule we learned is that on a "normal" day, the temp drops 3 degrees for each 1,000 feet of elevation.
I use the temp guage in my truck to amuse myself and know in general what the weather is like on the outside (good to know on a long trip) but I would not use the gauge to do any scientific experiments.
Chip
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