Turn Signal Issue... Remote Starter?

[MrClean]

I just fixed a malfunctioning left turn signal on my new 2000 7.3L Excursion. I was hoping to get some insight on what type of after market device was wired up incorrectly.

My symptoms were: When my foot is not applied to the brake, the left turn signal flashes the brake lights for rear of vehicle and correctly activates the left turn marker for front of vehicle. When my foot is applied to the brake and the left turn signal is activated, brake lights are all solid in the rear of vehicle, and the left turn marker is solid in the front of the vehicle. The right turn signal worked normally.

It turns out there was a lone blue wire spliced and soldered into a wire coming off the brake switch above the brake pedal. When the brake pedal was pressed, this wire was then hot. The blue wire went from the brake switch, through the firewall, and spliced into another wire that I believe leads to the left turn signal. I cut the wire and my turn signal now works properly. When I put my left turn signal on, the blue wire oscillates between 0 volts and 12 volts.

My question is, what do you believe this wire was there for in the first place? My guess was that there was a remote starter installed at one time, and that the dealer I bought the car from screwed up when they took it off.

I believe remote starters are often tied into the brake switch, so that if someone without the key tries to use the brake to take the vehicle out of park, the vehicle will shut off. I also believe remote starters often tap into the turn signals, especially when an after market alarm is used. This sounds like a good guess to me.

My only problem is figuring out how the dealership could screw up so bad taking out the remote start. This blue wire appears to be continuous for its entire length. This means one of two things; someone would have deliberately had to splice the wire coming from the break switch into the headlights, or someone would have deliberately had to splice the wire coming from the turn signals into the break switch. It wasn't simply a matter of, hey lets tie these two loose wires together.

I am also concerned that this blue wire doesn't tie directly into the left turn signal, but instead ties into an undetermined system that is shorting with the left turn signal.

Can anyone lend any insight on my mystery?