I have a 1990 Volvo 240 Four Cyl, Automatic Trans. On the shifter is an Overdrive Switch which puts the car in Overdrive or takes it out when not needed. My problem is that the Switch will turn on on its own and not allow me to shift into overdrive. Or it will start up with the shift arrow on and not shift into Overdrive. Even with repeated pressing of the button, it will not switch. There does not seem to be any rhyme or reason what keeps the switch on or off. It will go a couple of weeks with no problem, because if I start the car and the upshift arrow is not on, I do not touch the switch. If I start the car and the upshift arrow is on I will repeatedly press the button to turn it off. Sometimes it works, sometimes not. There are times when the car will shift into overdrive on its own. It will start up with the Overdrive arrow lit, and then turn off itself. Any ideas?
I had the same exact problem with my 1989 Volvo 240DL. It was the overdrive solenoid switch that went bad. It’s located behind the dash to the left of the glove box. I removed the glove box to get to it. It’s small rectangular device with a connector.
Somehow I’ve been keeping my 89 running for 194000 miles. My goal is 200000 then I’ll probably get rid of it because, while I can keep it running, it’s rusting on the frame and I can’t stop that.