2004 mustang v6 large battery draw narrowed so far down to a large 30A fuse #2 in engine comprt

skwgolf

fuse marked headlights pulled it gets rid of draw but not sure why or ware

Steve Elias

One of the wires to the headlights may have broken insulation and is shorted to chassis, or something like that.

To diagnose further, see what happens if you unplug each headlight one at a time, then both.

If problem continues with both headlight plugs unplugged at the headlight-end, an ohm-meter can be used to identify which wire is shorted to ground. With headlight switch pulled slightly from dashed and in the "on" possition, touch one ohm-meter probe to the headlight power lead(s), and the other end to chassis/ground.
That should identify which headlight power wire is offending/shorted, if any (the one that pegs the ohm-meter showing short-to-ground is the offender).

thecardoc3

skwgolf said:

fuse marked headlights pulled it gets rid of draw but not sure why or ware

How exactly are you measuring the drain?

If you disconnect fuses 4 (10amp), 10 (10amp), 38(20amp) in the smart junction box under the left side of the dash does that have any effect? (pull them one at a time and check)