Alright, here's an interesting one for you. I was driving this '00 V70 non-turbo with auto trans one day. Had not had any trouble aside from a poor idle when warm. I make a stop, and the car will not crank.

Symptoms: turn key on, dash lights come on. Turn key to start, and I hear the relay click as well, I believe, as the solenoid. I also hear a high-pitched but quiet tone - almost like some kind of electronic warning tone. Panel lights dim but SRS light turns off while attempting to crank. But car is not turning over.

Battery and starter are good - I removed and tested both, for good measure tossed the battery on the charger (I am a manager at an auto parts store...easy deal). I also replaced the starter relay with a known good unit. Hot wire at starter receives battery voltage (12+). Did not get a reading at the small spade terminal on the solenoid, but I am not sure my ground was good while testing. Also tried to start in all gears as well as jam it home into park to see if there was any change on neutral switch. There was none. Reverse lights do come on when in reverse.

At this point, it's my belief that there's a bad ignition switch or neutral start switch. I took the covers off of the steering column and did notice something which raised some red flags for me - a small harness with three wires (solid black, black with red stripe, black with white stripe). The black with white stripe had been cut, the solid black looped around the starter switch and fed back into itself. One single strand had been pulled and soldered between the black/red and solid black, then amateurishly wrapped up in electrical tape. Is this the immobilizer ring?

Any ideas here?

Or...anyone have some wiring diagrams? That would at least help me see what I need to backprobe with a t-pin.

*EDIT* On a hunch, ran a jumper between the hot wire and the spade terminal for signal wire on the starter. It turned over; meaning good ground. So now I know I need to focus on anything which could shut that signal circuit down.

 

Found a full wiring diagram...lo and behold, that green signal wire to the solenoid makes its final stop before hitting the starter at the neutral switch. That'll be my next stop.