Ok, for you electrical guys..... I recently installed the overhead console with the LED temp/directional display...

When I powered it on for the first time and drove the truck around the block to calibrate the directional sensor, everything was working except for the ambient temperature sensor. The outside air temp. read " -40 " and it bounced around a few times until it settled at -40

All day today it read -40. I checked the OEM service manual and it read like this:

Circuit Test."

Ok, fair enough.. I went ahead and tested the sensor resitance and the circuit continuity....

SENSOR TEST
(1) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Disconnect the ambient temperature sensor wire harness
connector.
(2) Measure the resistance of the ambient temperature
sensor. At –40° C (–40° F), the sensor resistance
is 336 kilohms. At 55° C (131° F), the sensor
resistance is 2.488 kilohms. The sensor resistance
should read between these two values. If OK, refer to

Sensor Circuit Test

in the Diagnosis and Testing

section of this group. If not OK, replace the faulty

ambient temperature sensor.

SENSOR CIRCUIT TEST
(1) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Disconnect the ambient temperature sensor wire harness
connector and the overhead console wire harness
connector.
(2) Connect a jumper wire between the two terminals
in the body half of the ambient temperature sensor
wire harness connector.
(3) Check for continuity between the sensor return
circuit and the ambient temperature sensor signal
circuit cavities of the roof wire harness overhead console
connector. There should be continuity. If OK, go
to Step 4. If not OK, repair the open sensor return
circuit or ambient temperature sensor signal circuit

to the ambient temperature sensor as required.

When I tested the sensor at roughly 45-50 degrees farenheit in my garage..the resistance read 17.xxx K This reading for the resistance is within range, but it is WAY closer to the 131 degree range (2.488 K) than it is to the -40 degree range (366 K). I would think that a test in the 50 degree air temperature range would read closer to the middle of 2.4 and 366 (somewhere in the 180.xxx range) Is it possible that the temp sensor could be faulty even though it reads within range by the specs?

Secondly, the circuit continuity test showed continuity between the two harnesses, one under the hood and one under the overhead console. The one thing that I noticed was that I got continuity on only one of the cavities in the harness connector under the console.
Is that normal? For some reason I felt there should be continuity to at least two cavities in the wire harness.

Like I said, it seems like all of the other features are working well, except the temperature feature.

 

back up...

 

I had a dodge caravan installed the over head console Just plugged in and everything worked. Set zone for compass. If I remember It took a little bit for that sensor to read correct. Don't know why. It also was not very accurate. plus or minus a few. And at a idle for get it. Thats what happen in my case. Sounds like maybe a new or another used sensor.

 

Hmmm, if you just short out the connection in the harness for the sensor, then the console should read 131? If it did then you would know your wiring is good and probably just a bad sensor?

 

I am going to try this... simple check that I didnt think about

 

The sensor output is probably not linear and the computer uses a lookup table to determine which temp to display for a given resistance sensed on the sensor. You have verified that it falls within range such that the computter if sensing it should NOT be reading one of the extremes, ie -40 or +135 degrees. IOW the sensor is outputing a value which should not be interpretted by the computer as -40. Therfore the computer is not "seeing" the sensor. Per the diagnostic you have an open wire condition, ie broken wire or misconnected wire.

edit: an imortant thing to note: there are 2 ports on the computer which the sensor needs to be attached to. One end of the sensor should go to one port while the other port should be tied to the other side of the sensor.

 

Yeah I just went through similar issues. This is the replacement sensor I got, seems to work well so far.

http://www.autozone.com/autozone/par...mString=search

 

Well there was no problem with the sensor. I purchased a new one, and tried it out...no changes. The new sensor and the old had the exact same resistance when I tested them.

I took apart the wiring and tested continuity at all harnesses and there was continuity throughout. The only thing I can think would be connecting the auto dim mirror and/or the lighted vanity mirrors. these wiring harnesses are left unattached because I did not have either accessory.

 

Hello, Have you fix this problem?
I am upgrading my 2005 van overhead console from stock light only to CT one and stuck with the same temperature reading.

Thanks
wely

 

For my 2004 ram 2500 it wasn't plug and play I had to unpin the harness running down the driver side pillar and figure out which wires did what and I got everything except three and my overhead cluster reads temp -- it won't give me any temp at all and im having trouble figuring out which wires are for the overhead temp sensor it seems between the trucks the plugs are the same but the wires themselves are in different positions same thing happened when I added electric windows and door locks it took a good day or two of just testing and testing the lighting is weird in these trucks due to the canbus system so it's a positive only loop I found thst out when connecting aftermarket tow mirrors with puddle lights and marker lights now if I could just find which two wires at the overhead console are for the temp sensor I'd be finished haha I wish it was plug and play honestly I'm jealous yours was 😀