I thought I'd see if this could be done, as the Volvo-specific relay for the M46 overdrive is about $50 locally, and the "generic" Bosch five terminal relay is widely available and cheap. After resoldering, my original relay would only activate/deactivate if I moved the contact plate manually. Perhaps the coil is open.

Wired the generic up with jumper leads to the original socket, with:
Volvo #15 going to generic #30
#s 85, 86 and 87 switched straight across, and
#31 connected to #87a. Result: The relay activates OD if the OD pushbutton is pushed, but will immediately deactivate if the pushbutton switch is released.

I'd appreciate any and all advice or observations about substituting relays, adding a holding circuit, wiring the circuit, bypassing the relay and using the circuit of the early 240s, or whatever pertinent info you can spare.
I've searched the FAQ and found a nice schematic in the archives, at http://brickboard.com/GALLERY/images/3619.jpg but otherwise I'm up the creek here. Sure would love to have my OD back...

I don't think you can use a "generic" relay in place of the specific (electronic "toggling") style.

For example, 31 is supposed to be a coil circuit ground (per your referenced diagram), but you've wired it to an armature output terminal—one that usually a Normally Closed (87a).
--
Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.

I may have missed something in the above messages, but have you thought of a toggling switch to control the relay, as opposed to a momentary switch?

julian

No, julian265, I hadn't! But perhaps that is an answer. My old relay-less '76 245DL with M46 had a push on/push off kinda switch. Do you mean that type?
Maybe I'll just run down to the hardware or auto parts store and see...
If I find that it works, I'll start a new post to keep it on the front page.
Thanks!

Exactly that type. Hope it works - I'm wanting a simple solution for my AW-71...

Good luck!

julian

Thanks lucid, guess I'll need the real McCoy relay. I didn't even realize that terminal 31 was a coil ground...with one tab and one slot left, I just connected 'em. Thanks for the info.
Al