Feedback Request on fix to Overdrive Relay in '94 940

[lemire1]

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

 

[Peter K L Milnes]

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).

 

[tom callaway]

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.

 

[Mike F]

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.)