Roger, I think that is the heater switch but I'm not real sure - - - - a friend of mine rewired it and made some changes. It had a starter button which he changed over to a regular ignition switch and the wiring was pretty bad so he updated everything he could without butchering it too much. Good point on the three point but it will have to be attached to the inside metal cab shell which should be ok - - all I'll have to move is the roof insert so I can get a nut and wrench on the mounting bolt.