Air Compressor on a 83 GL1100 Interstate?

[sseidman726]

Hey y'all, I just got myself a 1983 GL1100 Interstate, and honestly it's not in too bad of condition. It's got 76,000 and runs and drives great. My only question is this: The previous owner said it has an onboard air compressor that no longer works, and showed me some controls by the lower right on the fairing. The controls look like a simple two way switch, just up and down, as well as just a typical air valve. I've never heard of the interstate having an air compressor before, but if it does I'd love to get it working again. Is this unheard of? Without it, is there a manual way to check/adjust the pressure on the shocks? (If yes, how?)

Thanks in advance for leading me on the right track!