I have a 1988 740 turbo.

When I went to leave work I put the car in reverse and accidentally hit the 5th gear button on top of the shift **** (5spd).

To my surprise the 5th gear light illuminated with the car in reverse. It reversed fine, and the reverse lights came on as they should. The only problem here is that 5th gear is actuated when the car is in reverse (I listened for the click below the car)

But there's more. When driving normally, all the gears are fine till I need to put it into 5th. As soon as I hit the button, the car actuates 5th normally, and the light on the dash illuminates normally. However; the reverse lights come on.

Any light on the subject would be greatly appreciated.

Thanks

Deemo Diablo

 

Lol, that's pretty nutty. I'm kinda new to these forums, but I'm not new to cars in general. I would say you have some wires crossing somewhere. Maybe a bad relay. I'm not intricately familiar with the set-up volvo used in regards to this, but I would say that would be a good starting point.

 

Nevermind, I fixed it.

Turns out there's a wiring harness coming through the floor to the top of the transmission that was... well. The jacketing had come off all the wires in the harness and had shorted across each other giving me these symptoms. So, as a temporary fix I threw some liquid tape on there and all's well.

The wiring harness is for the reverse lights and the 5th gear lockout. It's to the right of and above the 5th gear solenoid. On the driver's side.