Problem with heater/vent lignts not comming on when the headlights come on.

[blau]

Hello,

I have a 2000 ML 320. The heater and vents lights to show the fan speed ect is not comming on when the head lights come on. All the other dash lights seem to come on the radio, speedo, control switch for the windods ect seem to be working except for the heater and vents lights.

I have one of the older ML that have the older style fan speed and temp control. Is the lights a simple system (old fashing mini light buld connect to the dash light electrocal system) or is it connected to some computer that can be set or reset?

What could be wrong? Where should I start to look for the problem?

I have disconnected the battery recently. Because the ets and esp light is comming but I replaced the famous break switch seem to fixed it. Could I have disconnected some when I am changing the switch.

Will disconnecting the battery again reset it. I don't want to disconnect the battery again if I have no chance in fixing the heater light problem.

thanks