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2002 ford excursion v10 2wd xlt without fog lights 203xxx miles

Problems:
1: 15 amp fuse pops everytime you turn on the running lamps/head lights
2: separate 15 amp fuse pops when truck is put into reverse, losing turn signals, reverse lights and overhead console.

Not concerned with problem 2 right now, working on problem one, although they could be related.

So far I have tested continuity on the tan/white wire from fuse box to headlight switch. Good.

Ran a unfused jumper wire from to the tan/white wire. Got running lamps, I don't believe taillights, and unsure of dash lights. Wire got hot, unplugged immediately, obviously there is a short to ground somewhere.

Order a new headlight switch, still waiting on it.

So far I have unplugged the following and tried turning on the running lights and still blows a fuse:

-Harness on frame rail half way down truck.
-4 plugs on drivers inner wheel well under the hood under master cylinder
-Both front running lamp sockets, each side
-dimmer dial on switch
-cluster (along with radio, 12v cig lighter, back up sensor switch, Defost)
-fan plug on passenger side firewall

I have chased the white/tan wire and some of the brown wire without finding the culprit. I have been trying to isolate the problem but no luck.

Factory stereo. Brake controller plugged into factory plug (now removed). At one point had an alarm system but has since been removed and those were tapped on, not spliced in. Also checked for worn overdrive switch wire in column to be shorting out.

Any ideas?

 

So when Ford put the receiver hitch on they smashed a loom of wires between the nut plate and the frame rail. I guess after 200K miles it finally worked through the wires. Had to drop the massive fuel tank to find it.