In my last couple of trips I have found that the engine did not shut down when the start switch was turned to the stop position [anticlock] .After a couple of goes it stops , anyone else had a problem and if so what was the fix . Cheers Geoff
I think it is either the contacts at the key switch end or the contacts at the solenoid. I've had this happen before too. If you 'wiggle' the key as you turn off, it may stop a bit quicker. This probably means it's a contact problem at the key switch end. It may also be a tricky connection by the fuse for the solenoid, or dodgy contact at the solenoid. It may be a broken solenoid though this least likely. So, probably a case of tracing connections, emery cloth and wd40. At least that's the cheaper option to try first.
I don't know what type of engine you have, but it's always a good idea to find where your manual shut off switch/lever is at the engine end - just in case the key method stops working entirely.
My MD22L, which may have a similar setup, had a related problem. In my case the engine would not start. :o The quick fix was to disconnect the wire to the solenoid and stop the engine by hand at the solenoid. Bought a new starter switch and it was not cheap being Volvo. :-[
The problem was solved...for a while! Again I could not start the engine, and this time it was "very inconvenient", :-[ but that is another story!
Pulled the starter switch out again and noticed that the problem was very intermittent. The cause was the multi wire connector just behind the switch, has about 15 wires from memory. One of the connectors inside the multi, was very tarnished and had become unserviceable. I made up a by-pass and all is well. And I now how have a spare starter switch. :D