So I recently started having a problem in my 1991 volvo 240 where the shift overdrive will come on by itself whlie driving. It's not a big problem while driving around town (at least not to my knowledge besides that the arrow bothers me hehe) but on the highway it is obviously a problem. Sometimes I will be going 85 mph and the shift override just comes on and puts me into third gear. The kicker is = I can't turn it off! The switch just won't work! I press and press but nothing. Eventually ten minutes later it will either: a. turn off automatically. or b. finally the button will work and turn it off. Does anyone know why this is? I've read about problems where people are suck in park and need the shift override and something about a recalled switch... is it similar? How much would this cost to repair? Any help is GREATLY appreciated!!! I'm supposed to move from California to Massachusetts this summer and drive this thing. Everything else I either just replaced or is in great condition. HELP!

 

I don't think the release switch would help in this sittuation. It's located inside the track where the stick goes down...infact, there may even be a little note printed on the plastic with an arrow.

Sounds like you either have a short in one of the wires, a fuse is going bad, the fuse box is getting too old and corroded or the overdrive relay is going bad. The fuse box is relativly cheap and fuses are dirt cheap. a new relay is about $50 but i'm not sure of the ease of installation. I've no clue what you're looking at if its a short.

 

Overdrive relay located behind the Glove box and to the left.

 

I used to have the same problem - and it turned out to be the relay.

You can most likely fix it by taking off the orange or white cover (depending on year i think) and simply resoldering the joints on the bottom of the circuit board.

This method worked for me, though i had to repeat the process every six months initially, but now it hasn't played up for years. Do a really thorough job and you'll be fine.

 

FYI, I bought the relay for my 86 240DL online from FCP Groton; about $30 plus shipping.