It runs off 12 volts, trace it under the steering column and unplug it. You can download a service manual for your year ski to find the color code and wiring schematic you're looking for. To harness 12 volts directly to it, take your ski's battery and move it near the front in the ski close to the plug. After unplugging, get some small jump leads to tap the plug and send 12 volts to it. If doesn't work doing this test it's bad, you can order a 12 volt beeper or visit the local Radio Shack if you have one still open near you.
I picked one up for less than $8 shipped, don't recall the stock number, search ebay, any 12 volt beeper of comparable size will do. Removing the top steering cover, I snipped the old one out and soldered the new one in. It didn't quite fit exact, but I trimmed and zip tied it.