Volvo Repair: overdrive, rubber boot, glovebox

Question
I do have mechanical skils.  180,000 miles on a 1987 240gl.  The overdrive function keeps going on by itself, illuminating the light on the dash and dropping into 3rd gear.  If I hit the dashboard it'll turn off.  Thats the only thing I have found so far that seems to turn it off.  What do I do?

Answer
Hi Dan,
         The OD relay is behind the dashboard...near the glovebox...on the left.
        Remove glove box screws...look to left...sort of sitting next to dashboard is this relay.
          While driving car..tap relay to see if it shuts off or goes on...these relays fail often.
         Install new relay...
          Wiring that goes thru gearshift rubber boot can become broken or frayed.
              Good luck,
                         Bilbo