1983 380SL Battery Light problem

[christordnine]

Hello,

This is my 1st post here and I need a little help with a friends 1983 380SL

the car has been outside for about 2 years and Rats had been in the engine compartment and not only built a nest on the passenger side below the
heater valve but they also ate some wiring and Yes, I repaired the warm-up regulator wiring and thermostat wiring along with some other places but....

I started the car and starting going through a check list for all the electrical
consumers and found that the blower fan is inoperative and also the battery light does not come on period.

Doesn't the charging system use the bulb for completing the circuit as most german cars I have worked on?

any help would be appreciated

Christo