Greetings, all!

My M46 won't kick in the overdrive. All the wires are connected underneath on the trans. I've traced continuity from the shifter OD switch wiring down to the harness plug on the passenger side of the tunnel -- OK there. The fuse (#11) has continuity. The wire which plugs into #15 on the relay carries 12 volts when the ignition is on. I pulled the relay and resoldered all the connections on the circuit board and cleaned up the male connector prongs. Yet, I still can't get the relay to fire. Is it truly dead? ...or...is there some reason that a malfunctioning 4th gear switch on the trans could prevent the relay from firing? ...or...some mystical incantation that I'm missing?

Assuming that its a dead relay, am I condemned to get one at the local Volvo dealer ($$$), or is this a common relay that a good parts store would carry?

Thanks!

Rob

if the fourth gear switch is bad, you could always do what I just

did the other day and make your own. ;-)

read the posts for more information, and maybe I'll post some

instructions on how to destroy your transmission. [ double ;-) ]

Yes, you are right to suspect the 4th gear switch. That will give the symptoms you see. It is accessible with a 7/8 deep socket at the right/forward upper part of the tranny.

Morning, Bob!

Thanks to you and the other posters for your advice.

I'm assuming that to get to this fourth gear switch on the upper right of the trans body that I need to remove the lower crossmember and allow the trans to sag down? Will there be enough clearance to get a deep socket plus ratchet head up in there, or does the trans (heavens...) really nead to come out?

Rob

I think you can get it without dropping anything. In fast I do it without jacking the car up. The deep socket and small breaker bar I use just fit. A ratchet head is too big. One of the benefits of haveing a garage full of spares from the p 'n p is you can practice on the donor tranny that you take the switch from.

"Will there be enough clearance to get a deep socket plus ratchet head up in there..."

Yep. You might find a universal adapter on a 3/8" breaker bar works best. In fact, you may not need the universal adapter. With that switch (if it's anything like mine), all you need to do is break it free—like 1/16th-turn—and it should be finger tight from there.

Watch for the tiny metal gasket.

"...need to remove the lower crossmember and allow the trans to sag down?"

I've done several on my cars over the years — and for me, allowing the tranny to "droop" is very helpful.

Don Foster (near Cape Cod, MA)

Try a continuity check to ground through the 4th gear switch before assuming the OD relay is dead.