DODGE RAM FORUM banner

1 - 7 of 7 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter · #1 ·
The out side temp stays at 54 C all the time...so I changed the ambient sensor at front of hood which didn't help! I checked the wires for power before I buy new wiring but I'm not getting any power!

Does any one have a schematic or can someone tell me which of the two wires should have power if I splice it?

Any other ideas or help greatly appreciated!
Thanks
 

·
Registered
Joined
·
72 Posts
im not exactly sure what you mean by all the re-wiring talk?

stupid question but have you pressed and held the reset button?...... one time mine said -30 degrees Fahrenheit and i held reset until it went back to zero and then it started increasing until it read normal.

my 2 cents.
 

·
Registered
Joined
·
3 Posts
Discussion Starter · #3 ·
Yes I tried the reset button! For 2 or 3 years the temp has jumped from -40C to 54C.
Not even close to temps in this area! Every other function on console works except the outside temp... which would indicate it's the ambient sensor! I pulled the fuse and waited the 10 secs sugested by dealer, but the problem seems to be no power going to the ambient sensor.

Thanks
 

·
Registered
Joined
·
500 Posts
The sensor will not likely have any power on it. It will be a resistive device (RTD) or a thermocouple that will change output based on temperature. Ohms if an RTD, milliamps if a thermocouple. Not sure where it is wired back to but I would lay hands on the harness back to it's source. A schematic will make it much simpler to track down and you can check connections on both ends before going thru the trouble of checking the entire harness.
 

·
Registered
Joined
·
24 Posts
Here is how to test that system right from the chrysler site, hope it helps out:

Caret1>AMBIENT TEMPERATURE SENSOR

The thermometer function is supported by the ambient temperature sensor, a wiring circuit, and a portion of the compass mini-trip computer module. If any portion of the ambient temperature sensor circuit fails, the compass/thermometer display function will self-diagnose the circuit. If 55° C (131° F) appears in the display, the sensor is being exposed to temperatures above 55° C (131° F), or the sensor circuit is shorted. If –40° C (–40° F) appears in the display, the sensor is being exposed to temperatures below –40° C (–40° F), or the sensor circuit is open.
The ambient temperature sensor circuit can also be diagnosed using the following Sensor Test, and Sensor Circuit Test. If the temperature sensor and circuit are confirmed to be OK, but the temperature display is inoperative or incorrect, refer to Compass Mini-Trip Computer in the Diagnosis and Testing section of this group. For complete circuit diagrams, refer to Overhead Console in the Contents of Group 8W - Wiring Diagrams.
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.
  4. Remove the jumper wire from the body half of the ambient temperature sensor wire harness connector. Check for continuity between the sensor return circuit cavity of the roof wire harness overhead console connector and a good ground. There should be no continuity. If OK, go to Step 5. If not OK, repair the shorted sensor return circuit as required.
  5. Check for continuity between the ambient temperature sensor signal circuit cavity of the roof wire harness overhead console connector and a good ground. There should be no continuity. If OK, refer to Compass Mini-Trip Computer in the Diagnosis and Testing section of this group. If not OK, repair the shorted ambient temperature sensor signal circuit as required.
 

·
Registered
Joined
·
1 Posts
I have been having the same problem...-40 on the console, and I replaced the temp sensor with no change. Then I happened to look under the hood insulation and see that critters (squirrels) have chewed on the wiring going to the temp sensor.
So I guess I'll have to look into running new wire over to the sensor.
Any idea on type of wire and where to purchase?
 

·
Resident Technician
Joined
·
14,202 Posts
No need to replace the harness. Just cut out the bad sections and splice in a new piece. Make sure you seal it with heat shrink.
 
1 - 7 of 7 Posts
Top