Originally Posted by
Bayliner12
my outside air temp is reading -36, I replaced the sensor but it still reads the same, I disconnected the battery for awhile hoping it would reset, but it did not, AC works fine and its not giving any codes. any ideas? TIA
It's a simple circuit driven by the Instrument Cluster's microprocessor. Here is how it works:
The GREEN wire is a constant current source and with no sensor plugged in, it should have 3.00 volts in it, referenced to ground of course.
The BROWN wire always shows about .05 volts, it is close to ground.
Both wires go directly to the connector at the Instrument Cluster, if the display lights up, it is not a fuse.
At 3 volts, the display shows -36F (or C equivalent).
The sensor is a variable resistor and its resistance goes lower as the temperature goes higher, 91F (or it's C equivalent) will lower the resistance of sensor such that the voltage will drop to .96 volt.
To measure the voltage with the sensor plugged into it is impossible as there is no exposed contact on the back side that you can get to. I used a "tap" to measure the voltage both with sensor unplugged and sensor plugged in with the garage at 91F.
NOTE THAT IF THE BROWN wire is open, you will have 3 volts on the green wire and a temp of -36 at all times. So with the sensor plugged in, you should see around 1 volt on the green and ZERO on the brown.
I strongly suspect you have an open in the green wire, probably right inside the connector at the sensor, tho it could be father up towards the IC but the manual claims there are no other connectors in line between the two ends.
