The third gear light on dashboard won't go out. Won't shift into overdrive, is there a solenoid I need to replace?

 

Volvo AW70/71 Overdrive Solenoid Bypass Replaces 1239928 1239679 >>BACKORDERED<< | eBay

That is what I did to fix my 240.

 

Hi there. Same problem with my 940 lpt celebration. Fitted bypass plate and now changing up to 4th but on the solenoid there was a cable approx 9 inches long extending to a sensor of some kind lower down on trans box. I cut this cable but I don't know what it is for. would appreciate any help you can offer. Did you have this as well? Thanks.