Trans Light on when the Run Switch is Off?

[Mogman]

All the circuits he is concerned with are 12V. with the exception of the 24V relay coil that switches the 12V on and off to the transmission with the run switch, which appears to be working, If I am correct his only issue is the residual trans light when the run switch is off.

 

[TOBASH]

Mog, that’s what my questions are meant to confirm brother.

 

[gungrubber]

Mog, that’s what my questions are meant to confirm brother.

Having the same problem with a 1097A2. Have a 3.5 volt current to the trans light with ign. switch off. Replaced the 12v relay with no improvement. The TCM has a constant 12 power supply and I’m thinking the module is feeding the light from this source. Something fried in the TCM ?

 

[Mogman]

Which side of the trans light?
Is it the side that is switched by the relay (290/291) OR the side going to pin U (657A)
That is what I asked the OP for originally.
My suspension is it is being back fed from pin U (657A) and seeking ground through 290/291, this would assume the LED is set up so it would not matter which way it was connected as this would be reverse current flow.
If this is correct and all other functions of the TCM work (shifts etc.) a diode could be placed in line with the lamp to extinguish it, as long as what ever has failed and allowed the "backflow" to occur is not causing other parasitic drains on the battery.

 

[Mogman]

These measurements would be made from the wires 290/291 and 657A to ground with the lamp connected.

 

[DHumvee]

These measurements would be made from the wires 290/291 and 657A to ground with the lamp connected.

How do you get a probe in there with the lamp connected? Is that the female side?

 

[Mogman]

You use a sharp probe and pierce the insulation.