sharrack

Hey Guys,
I've asked this question on another forum and never got the answer.

Late model vehicles have digital outside temperature gauges that read the accurate ambient temperature even though the car is baking in the sun and the engine is cooking at over 200 degrees.

How is this sensor isolated to prevent false readings for other heat producing
forces.

I've tried simple digital remote weather gauges but they are always influenced
by sheetmetal heating up, engine heat etc.

I'd like to adopt this and retro fit it to my 99 runner.
Thanks...... Kenny S>

19RUNNER86

they are usually located down by the front wheels. either that or in front of the radiator...

mastacox

They aren't ALWAYS accurate when the car has been baking in the sun, but usually the probe is located near the front of the car, in the bumper or valence.

You can't expect the thermometer to be accurate if the car has been sitting in the sun, but while driving if you make sure the probe is directly in front of the radiator, the car's fan will assure that ambient temperature air is always being pulled over it.

sharrack

Somehow I think it's more complicated than that.
Here in AZ, ambient temps can reach 110 degrees in the shade and all of the vehicles panels are baking at way more than that.
Yet.........even after cooking in the sun for hours, the digital thermometer will read very close to the ambient temperature.
I've tried basic digital thermometers BUT they always max out even while under the vehicle from engine temps, road temps and the sun.
Still not convinced it's as simple as mounting it near the bumper..
Kenny

5-spd for life!

Usually the sensor is located on the front bumper valence. The sensor has a plastic shield around it so the bumper/engine/whatever else will not affect it that much. The plastic does not transfer the heat like metal will and if you put the sensor in front of the vehicle enough, the engine/radiator will not affect it too much. When you drive, that is a whole different story because like what mastacox said; the sensor will have ambiet air pulled over it and there will be no hot air from the car to influence hotter readings. This is why OEM ambiet air sensors will usually be accurate "enough".

seanz0rz

so what years of toyotas (any model) came with a temp display inside? im guessing 4th gens. wonder how hard it would be to carry that over to a 3rd gen?

nc994run

My 99 has the outside temp sensor, i have the digital temp controls, so it may be on all of those with the digital controls

midiwall

For what Toyota would charge you for the stock one, you could buy a few aftermarket units:

http://www.jcwhitney.com/autoparts/P...002620/c-10101

http://www.jcwhitney.com/autoparts/P...002620/c-10101

http://www.jcwhitney.com/autoparts/P...002620/c-10101

http://www.jcwhitney.com/autoparts/P...002620/c-10101

seanz0rz

too bad none of those are LED or VFD.

what i really want is something like:
http://www.agedstock.com/images/newv...le_0_minor.jpg

where the numbers are lit, its not just an lcd, or even a backlit lcd.

well im lookin around and do not see anything i like. ill probably go find one from another vehicle and swap it in.


or my carpc supports a thermometer input, so i might just do that... and then pull the ambient temp from the motherboard.

sharrack

NC994- Could you post a photo of the sensor and how it's mounted??
Would be a big help. thanks.
KennyS>

sharrack

I just picked up a slimline onboard temp gauge from wally world for 10 bucks
and did the velcro thing to the left side of the steering wheel.
I ran the wire through the firewall and let the sensor hang free right under the left foglight for free flowing air.
I'm sure the radiant heat from the engine and radiator will still throw the
reading off at idle and when the car is parked.

Should I have let it hang to the rear of the car on the drivers side away from the exhaust and away from any engine components?

thats why I can't undertand how the late model cars gauges give accurate readiings with them being so close to the engine and radiator. Kenny S>

midiwall

They're not "that" close. The thermocouple (temp sensor) is usually sheltered in a plastic housing in a fender and it doesn't have a lot of mass, so it won't retain any heat that it may be exposed to.

sharrack

I think my main issue with inexpensive digital gauges is that they will max out in AZ. when the car is at a stop or parked and will take 10 minutes to return to actual ambient temperature. 2 degrees at a time from 155 degrees down to the ambient.
I'm just trying to locate the best spot under my runner that is out of the sun and away from any radiated heat source so I can place my sensor.
In an effort not get in my car and NOT see ------ on the digital read out.
Kenny S.