In one of my previous posts I installed a Webasto HTM T100 remote to control the MES-DEA RM4 heater. The remote works perfect, it shows the actual temparture in the car and has a great range.

Unfortunately the MES-DEA heater isn’t connected to the PEU and in the situation that the PEU isn’t charging the battery, the heater drains the battery which affects the range. To prevent the heater to “drain” the battery the PEU charge mode needs to be enabled.

By feeding 12v into pin 8 of connector J1 (see Interface Document for the AC-150 Gen 2 Electric Propulsion System) the APS (auxiliary power supply) turns on and when connected to the grid it will start charging.

Wiring schematic Webasto HTM T100