Volvo Repair: overdrive relay on 87 240 dl, overdirve, shroder

Question
Hi there.
  I have an 87 240 dl wagon, automatic.  Occasionally the overdrive would be activated at ignition, sometimes immediately going off sometimes not until 10 or twenty minutes down the road, not shifting into 4th  until the indicator turned off.  The stickshift button to activate/deactivate overdirve does not work.  In the last week, overdrive has stayed on all the time, and car won't shift out of third at highway speeds. Is this just the overdrive relay, or possibly a more serious problem?  I never use overdrive, I would just like to be able to drive in 4th gear when necessary.  I have very basic skills, car has 133,00 miles.
thanks.
Steven Shroder

Answer
Hi Steve,
         The overdrive relay is my first choice of fail parts.
         It's located inside the dashboard..remove the glove box...super easy...look to the left it's a few inches away...it's usually white.
             Good luck,
                          Bilbo