One writer already mentioned this.

Wire often breaks in tranny tunnel, at rear of tranny where it joins the driveshaft.
It comes down into tunnel from the shift box above, then goes forward along passenger side of tunnel. The break usually leaves about 4 - 6 inches of wire hanging from top of tranny tunnel. Hard to reach.

Skinny under and have a look.
No amount of replaced electrical components will help you if the wire's torn.

Like I said, you guys are great. Thanks for the assistance. And excuse my stupidity on the engage/disengage of overdrive. Do you guys know anything better than the haynes manual for diagnosing such problems?

Your overdrive is failing to engage. The arrow light means your tranny is in direct drive (i.e., 3rd gear).

It could be as simple as a blown fuse 11, or the fuse is making poor contact.

Could also be a bad OD relay, or poor contact at the relay harness plug. To access the relay, remove the 7 screws around the face of the glove box and remove it. The White OD relay is just inside to the left, probably held in place by a steel clip.

Unclip it and turn it around so you can take the plug off and on a couple of times, then see what happens when you turn the key on. If it works (clicks) the arrow light should go off -- and you should be able to click the relay on and off with the shifter button.

If the relay is bad, it can be bypassed by a jumper wire (flat terminals on each end) inserted in the harness plug, between the terminal with the Blue and Gray wires and the terminal with the White wire. If all else is OK, your OD should work with the jumper in place.


There should be a plug screwed into the sampling port in your exhaust. I think it's a metric thread, maybe 12.0x1.5mm. Try an large hardware store for a short bolt with that thread. If I'm wrong, maybe someone here will correct me on this.


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Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.

There's a test port in the pipe about where you see it; yes, there'a plug for it. Try a dealer or a junkyard.
You can easily, with no damage, go 95 MPH out of OD; don't sweat it, but, still, get it fixed.

No sweat-overdrive relay- remove glove box reach back behind radio white rectangle box 3inches long-
Remove and replace
or wire to solenoid fell on trans is shorting out or solenoid is bad-
ebay has od relays cheap-good luck

First a point of clarification just so you'll get good answers to your questions in the future. Your car is stuck OUT of overdrive, the OD is there to reduce engine revs, like a 4th gear, you're stuck in 3rd if the revs are high.

99.9% chance your overdrive relay is failed, when it fails no 12v goes to the solenoid and the car only uses 1-2-3. Do a search on resoldering the relay, you'll find lots of information and some good pics folks have put up.
Good luck.
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Dave Shannon
Spring Valley, California
'67 1800s
'73 1800ES
'88-240
my pages