Ok, Based upon key testing code, (indicated short between dash overdrive to solenoid in transmission), I replaced switch. Overdrive still not working. Is that a definite indicator that it is the overdrive solenoid? What about the engine sensor, etc?

Chrysler tech replaced the brake light switch based upon recommendation by training center. I don't see that they are related by the wiring diagrams in the service manual.

How difficult is it to remove the overdrive solenoid?
Perhaps a diagnostic at AMMCO transmissions?

BTW: 1993 Grand, 242cu. in., AW4 tranny, 4X4. Additional info: Can be shifted into 2W or 4W, and 4W low. Shifts hard though. Vehicle did have some damage reported on car fax. Would it be easier just to replace the tranny, if so who is a reputable dealer in trans?

 

as far as i remember from yesterday, while seeking for dashlight related fuse which was blown, on passenger side panel at bottom front right, there was a fuse for o/d. can it be that simple?

 

Wish it was. Been there, done that...lol.
I've checked all the related fuses. I replaced the OD switch on the dashboard. I'm thinking there's only 2 other possibilities? Overdrive unit or overdrive solenoid.
Other thoughts might be speed sensor?

Appreciate your response and future correspondence.

 

i think your looking at the solenoid. not sure but you might be able to get to it from the tranny pan. maybe. but since you have codes its a definite electrical prob

 

Appreciate everyone's comments. I noticed the other day driving down the interstate that when I pushed the OD switch on the dash, the engine rpms dropped about 100 rpms. Is it possible that the solenoid is working and the overdrive unit is bad?
What about the possibility of the engine speed sensor?
Either way, through your help, I'm getting closer to the answer.
Thanks much.