Firewall Access

[de3jr88]

I want to add an in-car heater to my '04 Montana. I am having trouble finding a good point of reference on the inside firewall so that when I drill the small hole necessary for running the wiring, I don't drill into something that is shouldnt be drilling into.

Any suggestions?

 

[Steelcity]

Depending on how many wires you are adding or the size of the wires you can sneak through where the factory harness goes through

 

[de3jr88]

The cord is a standard 14/2 wire so its the same size as a 2 prong household extension cord. I havent been way up under the dash yet, was hoping to find some access behind the pedals.