What's the deal? Volvo OD's don't work on Christmas? I can't believe there were three or four posts from yesterday all relating t OD's. On the way in to work this morning my OD (M46) disengaged on it's own. Light went out. I clicked it back in, it held for ten seconds, disengaged, light went out.
All the way in to work, I could press the button (not a slider), would sometimes hear a click, sometimes I wouldn't. Sometimes the click would be followed by OD engaging and the light coming on, sometimes it would click but nothing would happen, no light, no OD.
It appears that the OD light is working as it should, I pulled the shift knob off and checked the wires/spade connectors to the switch and they look fine. Does the intermittent "click" suggest relay behind the dash or OD switch on the trans?

My bet would be the switch for 4th gear on top of the transmission on the passenger side. Can be removed without dropping the transmission. I had an identical problem with my 82. Changed the switch, end of problem.

Another failed 4th gear switch. It's the cold weather. Try this next timeit goes out. Re-engage then hold shift lever back and to right. It will most likely stay in OD until you let up on the pressure.

If you can get the dashlight to go out by also wiggling the shift lever, that also points to the 4th gear switch.

Resolder automatic trans relays, find the problem in manual trannies.

Duane

Replace or repair the OD relay, it's the culprit.