Thanks to several posts in this newsgroup, I was able to identify the culprit behind the overdrive light sporadically coming on, one time while driving 70 mph on the highway, resulting in a sudden drop down to 50 mph! As I know many of you know, this has to do with a faulty overdrive relay (grrrr - not only a lousy design but dangerous as well!!) Anyway the newsgroup posts allowed me to locate the overdrive relay (behind the ash tray), remove it, and pry off the cover. Several posts suggested cleaning the contacts and resoldering the joints. These looked very clean to me and I solved the problem as follows: In the center of the circuitry, there is a small magnet coil and a small switch relay attached to a spring. The relay is normally up when power is off. When the car is normally started, the magnet is activated and the lever pulled to the down position. This seems to be what turns off the overdrive. In my case, the relay sometimes seemed to get "stuck" and did not make contact in the down position. Since I NEVER use the overdrive nor would I ever want to, I simply permanently forced the relay to stay in the down position by wedging a small piece of wood between the upper contact and the upper surface of the relay. This seems to work great and -- assuming you don't need the overdrive -- a fairly simple way to solve the problem. I'd be interested if anyone has either tried this same solution, or knows of a problem that could result. Hopefully this might help someone else out someday! Mark
It seems as if you are in USA/Canada by your email address. You would be placing a greater strain on the engine through non-use of Overdrive which is the equivalent of an extra gear in your gearbox. I assume therefore that you have an AW autobox where the Overdrive unit acts as fourth gear. With the overdrive "arrow" off the overdrive unit is working and giving you four gears. You may have the AW box that has Lockup facility. In this case you have the equivalent of five gears. If however you have a manual gearbox (M46 plus overdrive) then the "5" lamp has to be lit whenever the overdrive is working. Thus if your overdrive lamp is an arrow your overdrive unit is working perfectly with it out and if your overdrive lamp is a 5 then your overdrive unit is not working. All the best, Peter. 700/900/90 Register Keeper, Volvo Owners Club (UK).
I just dealt with this problem last weekend on my '84 245. The relay had been acting up for a long time. I grabbed another one from a pnp yard and it was worse. All it would do was buzz and make the OD light flicker. Finally, I got around to messing with it. The solder joints looked fine to me even with a loupe magnifier, but the Volvo gurus said to reflow all the solder joints, so that's what I did. I also used some very fine sand paper on the contacts, by slipping it in there, applying some pressure to hold the points together and carefully pulling out the sandpaper. I put the relay back in and it worked perfectly. Then I did the same things to the one from the junk yard and it works great too. Now I have a working OD and a spare relay in the glove box. The soldering thing really works, even if it all looks good. Not at all hard to do--well worth the trouble. I feel like I beat the local Volvo dealer out of 65 bucks twice.
Isn't that just the best feeling in the world? (Well almost) -- Mike F. Thornhill (near Toronto), Ont. Replace tt with t (twice!) and remove parentheses to email me directly. (But I check the newsgroup more often than this email address.)
