It doesn't work and the switch does not light up unless the ambient temp is low. It actuates the exhaust restrictor which is well known to stick shut. Best to leave it switched off or to diasable it. Pattern replacement exhausts are available with a straight through pipe which means you can dump the critter.
The ceramic heater is just an electric heater fitted to provide instant cabin heat with a cold engine. It works well and needs the heater control switched for maximum heat and the blower on to work. Superb.
Our trooper has
Two fairly small batteries is a more accurate description. This is part of the cold weather package which is standard fit in the UK. It consists of extra batteries, that damned exhaust shit, the good cabin electric fire and the diesel fuel heater element. Also seat heating on many models.
Huw