1982 245 with M46 with non-working overdrive.

Using an ohmmeter, found out the following:

4th gear switch is ok, resistance goes to 0 between red and black when shifting to 4th.

Wiring from overdrive button to the relay is bad. The brown wire is ok (0 resistance) connecting to where the 86 prong of the relay plugs into, but the blue one has no connection from the shift lever to the place where the 15 prong of the relay plugs into. The button itself is ok (0 resistance when pressed).

A short peek inside the center of the dash reveals lots of wires, some of which are blue. They would not exactly be an easy task to sort through.

Any hints as where to go looking for the correct blue wire?

The blue wire is power from the fuse. Runs along the back of the dash just under the center vent. Goes up and over the steering column to just behind the light switch then into the cowl just in front of and above the fuse stack.

At the relay socket, another blue wire runs down behind the passenger side cowl cover, under the carpet there somewhere is a two wire connector that then feeds up into the shift stalk.

If I read your post correctly, you have 0 ohms now between the brown wire and ground? You should not.

At the relay socket, with ignition OFF, you should get continuity (0 ohms) between the number 15 (blue wire) and 86 terminals (brown) only if the shift button is pushed. If you have continuity at any other time the wiring inside the stalk is shorting the wire and blowing the fuse. Most likely place for damaged wires is where they turn up inside the shift tube at the bottom.

There should be power to the number 15 socket (blue wire) when the ignition is on.

If no power to the blue wire socket with ignition on, the fuse (#11)is blown or corroded so bad it is not letting juice flow. Why it is blowing is another search.

Duane

Re: brown wire continuity

I get 0 ohms between the brown wire at the shifter and the 86 socket where the relay plugs in. However, blue wire at the shifter to the 15 socket where the relay plugs in shows no continuity.

At the relay socket, there shold be two boue wires into 15.

One is to the fuse panel, the other is down and under the passenger side center consloe cover, then under the carpet, a two wire connector,(blue and brounn) then the leads into the shift tube. Find the connector, then test both directions.

Most likely it will be a broken wire at the point the wires enter the shift tube. I'd replace/repair the brown wire also since it follows the same route and is subject to the same stresses.

Duane