Hi Kevin,

How has your starter behaved since you posted in June?

I've battled this same problem with the Bosch starter in my old 740
years ago, and it appears to be a chronic problem with Volvo.
With the 740 it would quit suddenly and turning the key would no nothing.
Then I could short the two starter solenoid lugs, and it would start normally.
It could fail to start the next day or go for months and suddenly quit again.

I tried a second starter with the same results, and believe that the current
capacity of the starter solenoid circuit via the ignition switch and switch
interlock and associated wiring is just barely adequate, making this an all
too common problem.

This could be improved with the addition of a simple high current SPST relay at the solenoid terminals to be energized by the existing wire from the shift interlock. The little 4 pin Volvo "K" relay would do, I believe it's a 50 amp relay. Maybe Dave Barton has a socket for it and it would be easy to install?
www,davebarton.com (Volvo wiring maven)

If your starter has been behaving, it's only waiting for some emergency to quit when you need the car the most to conform with Murphy's Law.

Keep us posted, Bill