No start - Running out of options

[SonicAdventure]

I think you are onto something with the key chip, but what about the ignition switch itself?

[RickHaleParker]

Would I be doing this to check voltage to them? As a way to eliminate the 'neutral safety switch' or whatever as the culprit?
Or is this a way to bypass the immobilizer?

Pins 6 & 7 are the neutral safety switch. Probe them for voltage. That will tell if the POS III voltage is getting that far or not.
If you are getting POS III voltage on one but not the other, put a jumper across 6 & 7 then it should crank.
Be warned: jumping 6 & 7 defeats the neutral safety switch and the engine can start in any gear and get away from you.

[blankenship]

Does the second key (won't turn ignition) have a chip in it? Try putting it near the steering column while you turn the ignition with the first key. The chip just needs to be close by, its actual position isn't read or anything.

Tried that, to no avail. I've read somewhere *never* to have two Volvo keys on the same keyring because there chip signals will interfere (?). Anyway, it would seem both my keys should have the chip...but I've cleaned both and even rubbed them agains the immobilizer antenna ring without success.
I'm very confused, too, about why the "Master" key I have which unlocks all doors and glove box won't turn in the ignition. I'd guess that meant the ignition had been replaced at some point, but then...why would the Valet key still turn it?

[blankenship]

I think you are onto something with the key chip, but what about the ignition switch itself?

Good question. I wonder if this would produce the same symptoms at the starter voltage diagnosed by abscate above? If so, is there a process to test the switch itself?

[blankenship]

SOLVED.
Solution was found on the site here on a post by Tonyx back in 2013.
Just a bad connection of the green wire at the bottom of the starter solenoid.
Wooooohoooo!
Thanks for the input, all.