My Vendo 39 has a small heater on the front of the coin mech. Has anyone seen this before? I assume it's there to keep the mechanism from frosting???

Jim is correct, they're used to keep the coin mech's from frosting up and to help evaporate any water/rain that got into the mech.(in an outside enviroment,) it's safer to leave then dissconected as they're running on line voltage and are just a power drain anyhow (especially since most machines this age aren't going to see an unsheltered outside vending service area again)