I'm trying to figure out what the symptoms are of each component that goes wrong with overdrive, as this is obviously a widely discussed topic on here. Does the dash light (OD OFF) stay on when the relay is bad, or does it not come on? What happens when the solenoid goes bad that's different? And how do I guess if the switch is failing? I have an '83 245 and the switch on the shifter usually works turns the OD OFF light on an off, though sometimes it doesn't want to work, but it usually does.But of the light clicks on and off, does that rule out, or point to the relay as opposed to the solenoid?

Wes

 

http://cleanflametrap.com/odwire/

Problems could be switch, relay, wiring (under car) or solenoid itself.

See the bottom photo caption for the OD relay test.

 

Happily, one of my neighbors is a Volvo 240 enthusiast, and has a pit in his barn, with stairs so you can get underneath the car. One of the wires coming down to the solenoid...that has the black covering...is intact, but the black covering is partially gone, exposing the white part. There's another wire down there, that has a bunch of electrical tape on it. Where is the kickdown wire located? It's a quest now. I wish my friend would hurry up and mail me the Bentley Bible though!

 

http://cleanflametrap.com/RMS.html

Sounds like a wiring problem, I wouldn't touch the kickdown unless it fails to kickdown properly.