Volvo Repair: 1983 Volvo 240 Auto OD, automatic tranny, volvo 240

Question
My son is just starting having problems with his OD not engaging on his automatic tranny.  It just started to happen.  He was able to get it to finally shift into OD by abruptly excelerating the car?  From some of your prior questions appears this is a problem with Volvo's.  Does this have a simular relay like the newer models and how do I troubleshoot this vs. the solenoid. Having the OD engaged all the time is not a problem either.  Can it be hot wired to stay engaged?  Thanx,  Chris  

Answer
YOU COULD RUN A POWER SUPPLY TO GIVE IT POWER ALL THE TIME.USE AN ACCESSORY POWER SO IT IS ONLY ON WHEN THE CAR IS ON.IF THE LIGHT GOES ON AND OFF AND DOES NOT GO INTO O.D. THEN IS COULD BE THE SOLENOID IF THE LIGHT STAYS ON WHEN YOU PRESS O.D. BUTTON THEN IT IS PROBABLY A RELAY PROBLEM.