View Full Version : Calibration of outside air temperature display
BigRedDMaxx
11-16-2002, 21:10
Anyone know if it is possible to calibrate the rear view mirror temperature display?? Mine is always off by + 4 to 6 deg F. I have relocated the thermocouple from the radiator support bracket to a location near the bottom of the air dam but no change in accuracy.
pinehill
11-17-2002, 01:55
What makes you think that it reads higher than it should? Consider that the temperatures immediately above highway surfaces are higher than off-highway ambient temperatures by several degrees due to absorption of sunlight by the road surface and to the exhaust and engine heat from other vehicles. To check, put a calibrated thermometer on the front bumper of the truck after it has been sitting cool in a garage for a day or so.
Last night we had freezing rain conditions and the temp was right around 32 DegF. While going down the road (sensor in stock 03 location) the reading in the mirror was 36deg but it momentarily flashed “ICE” (?). Has anyone else seen this? Does it automatically display ICE for a 32deg temp?
Bill,
Sounds normal, mine works exactly the same way. I found a web site a few months ago by the mfg of this unit & it confirmed that this is normal.
My temp. reading sounds about the same. I get the "ICE" msg. around 35 deg. F. Remember when the air temp. is above 32 deg. ice will still form on surfaces that may be colder so be alert.
hdmax(mike)
11-17-2002, 17:25
When we were having warm to hot weather mine read very accurate. But sense the temps have fallen to 20`s-50`s it is allways off, sometimes by 8-10*
My wife has a van, and it is allways dead nuts on. I believe the one on the new Silverado`s are a joke. They should either fix them, or quit using them all together. I turned it off a couple weeks back. It is a shame to pay as much for a truck as we have to, and get junk trinkets.
BigRedDMaxx
11-17-2002, 20:31
Pinehill:
I have checked it against several other sources, this is how I know it is off. If it was only off a couple of degrees it wouldn't bother me a much. At this time of year in Michigan, I can guarantee you that the road isn't radiating much heat! We're lucky to see the sun once or twice a week.
hdmax(mike):
Right on! The temperature readout in my Wife's car is accurate and it cost half as much as this truck did.
A simple test would be to put the sensor in a container of ice water and see how far off it is. Temp of the ice water will be 32deg F. This is the classic method for calibrating thermocouples.
Gasman1075
11-18-2002, 18:30
Has anyone found a place to mount the senor so that it will read anywhere near normal when you have the winter front on?
Gasman
Yes, in the slot between the bumper and the lights on the driver side. It is in the free air even with both covers on.
Gasman1075
11-18-2002, 19:26
Thanks John. I will give it a try. I moved it to the slot where the cover and the head-lite meets but that still gets real warm over there. Do you remember what you mounted it to?
Walt
I pulled mine and "Re-darted" it to the plastic splash pan down low. Seems pretty darn accurate to me. I have digital stat in shop and it always coincides within 2
Idle_Chatter
11-18-2002, 21:15
I relocated mine to under the left turn signal. The black plastic "skirt" under the signal had a hole already in it on the inside (towards grill). The sensor just clipped right in that hole with the little probe sticking out into the gap between the grill and the signal and the connector and wire under the light!
I figured the lights may give off enough heat to skew the readings so I kept clear of them.
Drive a mile, walk the rest
11-19-2002, 12:03
FALSE SENSE OF SAFETY!! Trinkets and Baubles!!
The temperature of the air is NOT the temperature of road surface. The air temperature can be well above freezing and you can have ice on the road.
TIP: Ice looks the same as water on the road. Watch the vehicle in front of you. If the tires produce spray, it is water. If there is no spray, black ice is starting to form.
Obviously, be careful on bridges, overpasses and shady spots. Drive safe.
car of the week
11-20-2002, 16:51
FYI--
GM HAS IT PROGRAMMED TO READ ICE IF THE TEMP. HITS 37 DEG. IT IS NOT A SOPHISTICATED THING, JUST A DEFAULT PUT IN THE MEMORY BY GM.
RYAN
Mine always reads within one degree of reports on the radio. I notice sometimes it reads a little high when the truck is warm and I just get started again, but it corrects when I have driven a few miles.
I can't answer the real question (can the sensor be calibrated), but I doubt that it can. I think you would have to replace the sensor.
Mine seems pretty accurate by the way.
Rebel_Horseman
11-29-2002, 08:19
Where is the probe that needs to be relocated? I know last night the temp on the bank sign said 31 and my mirror told me 38 and climbed to 42 by the time I got home. Where is the probe?
Reb [><]
Idle_Chatter
11-29-2002, 09:45
Horseman, it's inside the grill, mounted on the trans cooler bracket to the right of the cooler (looking in the grill) in front of the radiator. It looks like a little "button", has a connector on the back and some plastic armored wiring going down and towards the driver's headlight. I snapped off my grill, (pull black plastic top cover, remove one bolt by the hood latch and pull forward) unplugged the sensor and moved it over to an existing hole in the black plastic skirt under the driver's turn signal. Then I removed the bracket and popped the grill back on. Very important since I'm now running my "Winterfront" grill cover and the probe would have been reading temperature of air trapped between the cover and radiator instead of outside air.
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