Clutch switch

It's no big deal. If you can pull the pedal up and it works, it's the clutch pedal return spring ( maybe $65 installed at a dealer ). If it's the actual micro switch, and I'll bet it's not, it's just as easy fix, less than $100 installed.
I let the dealer do my Volvo cause you gotta take a bunch of the dash apart to get to it. They had like half hour into it, I'd turned it into half a day project.

 

I heard, if an engine shuts down with the Jake on, you can damage something, I know it's just not good.( which is why you have that clutch and throttle shutoff switch) I've had trucks with Jakes that didn't shut off with the clutch and was told to manually shut it off on the dash before the motor kills.

 

Dont see how having the jake on when a motor is shut down can do any damage. What you where probably told was shut the jake off so it dont kill the motor. As mechanical engines didnt have anything to tell the jakes the engine was at idle so they would still try to run with the engine ideling and would kill the engine. Ive driven an old big cam IV that the jakes where loose and it would actually idle with the jakes on. The jakes where only working on a couple cylinders so it shook, popped, and farted like crazy but still ran.