Thomas MVP Fast Idle Switch

[GrindingTraffic]

Hello all! This post is regarding a 1993 Thomas Saf-T-Liner MVP ER.
So we are working on our skoolie. Currently halfway through putting up outer sheet metal. But today we figured we'd go ahead and fire it up and make sure it'll still run since we haven't turned it on since February :P I was only somewhat familiar with the fast idle switch, which I knew that the left switch. After a couple minutes of it running, I wanted to turn on the fast idle. I flipped on the left switch, and I assumed the right switch was to adjust idle speed, but the switch broke very easily.
My question isn't so much asking how to fix it, but I am just trying to verify what the right switch in the Fast Idle controls is used for. If it is for idle speed setting, then I can't adjust the speed and is currently stuck at 1500rpm. I'll attach an image. Thanks a bunch!

[o1marc]

On my bus, flip the switch to the on position, rev the engine to desired high idle speed and flip the switch up to hold it at that RPM. On mine, the switch next to it is the cruise control on/off

[BarnYardCamp]

On my 2005 Thomas/Freightliner, with the bus running at idle, flip the switch and the engine speeds up to about 1200rpm..I start my bus almost every week and let it run 20 - 30 minutes on high idle. I've never tried turning it on as described by 01marc to see if it will hold the rpm's I set via the throttle.

you don't want to shift out of neutral with the engine at fast idle...(tranny may not let you)

[GrindingTraffic]

Thanks for the tip. I'll give that a try. Im happy that the on/off switch works at least.

[KlingonFiero]

On my 1994 Thomas Westcoaster the left switch does as described above, on/off control only.

The right switch wasn’t connected to anything, no wires to it at all. Maybe it was for a cruise control option that I don’t have???