I have attached the wiring diagram for the Heater.
The top fuse is for the heater. It gets its 12v power when the key is turned on.
Pull the fuse and check for power on right side with the key off and the key on.
If you have power then reinstall the fuse and check for power on the left side.
Sometimes the connectors get so dirty/corroded that the fuse doesn't make good contact.
The brown wire runs from the left side of the fusebox to the connector 6" or so from the switch.
If you have power at the fuse and no power at the brown connector then you will have to trace the wire or replace it. You can check the continuity of the brown wire by using the left side of the fuse holder and the connector you unpluged before
The Gen1 light comes on because of the power draw thru Gen1. It could mean that your alternator needs a rebuild in the future.
What doesn't make sense is that there is a power draw/short when the switch is turned on. If there is no power to the switch, how is it causing a power draw?????
One thing I would recommend doing not mater what is removing ALL the fuses and using contact cleaner and maybe some fine sand paper and cleaning ALL the fuse sockets. Of course you need to disconnect the batteries first....
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