Behind glove box
allows power distribution to the overdrive solenoid for overdrive engagement.
Behind the ashtray--google "Volvo 940 overdrive relay" for detailed answers on how to get to it. It's beyond the fuse panel, the white one with black print on the right.
BEHIND THE ASHTRAY IN THE FUSEBOX, A WHITE RELAY STANDING STRAIGHT UP.
under the dash, driver side
it should be behind the ash tray in the fuse box that is located there.
Try overdrive relay, you can buy them anywhere, replace old one, it is very easy.. I had to replace one on my 88 740. Give it a shot before you let someone work on it.
Remove the fuse from the fuse box. Or remove the relay.
behind the glove In the relay/fuse panel behind the ashtray. After you remove the ashtray and holder you will need to remove the box above it to access the relay
Yes I just did that to mine, and it works great. No problems.
Behind the center console to the left of blower.
Check either: Solenoid, Wiring, Switch, or OD Relay.
Try a known working relay in its place... I have also put my hand on the relay while someone is driving and pressed the over drive button on and off, you should feel the relay "click" inside.