Hello all. A little while ago my overdrive stopped working - suddenly. One day it worked and the next day it didnt. The overdrive light works fine but there is no sound to indicate the solenoid is working. About the same time i was doing some work on the indicators and the associated wiring harness. Is there a separate wire that goes to the overdrive unit separate to the wire that goes to the light on the steering column?

 

The overdrive takes power from fuse No 3 via green (G) wire. It's light in the column quadrant comes all the way from the 3 or 4 way/position light switch via the purple & yellow wire. (YP)

If the column OD switch is working the light should come on in the quadrant if there is power to the solenoid.

Likely problems other than a wire off:

~ Is the solenoid itself. You should hear it clicking. If it clicks then adjustment likely required. If the light comes on with no solenoid activation it is almost definitely the solenoid as light & solenoid are after protection by fuse & inhibitor switch but on our old cars you never know if someone has fiddled with the wiring.
~ The reverse gear inhibitor switch on top of the gearbox (Stops you engaging OD in reverse & blowing up the one way sprague clutch in the OD)
~ A blown fuse or break in the wiring ~ GB & OD has it's own sub harness.

Harness runs under the carpet on the LHS of the tunnel & through a grommet to the GB.

 

BTW ~ the overdrive warning light is wired as it is so it dims when you turn on headlights at night. (i.e via a dropper resistor in the light switch)

 

WBO ~ Did you come right with your OD activation?