Anyone know what the small wires on the starter solenoid are??

[BadMonkeyRacing]

Got the truck from my dad, started chasing ghosts. New fuel pump, pressure reg., all the relays, ignition switch, plugs, wires, cap, rotor, starter solenoid, all that. Truck runs great! (After I found that little negative wire from the battery that runs all kinds of stuff)
ANYWAY
Then I noticed the brake lights were stuck on.
New brake light switch! Nope.
Poke'n'prod around with my trusty test light, find a rats nest of wires at the rear bumper (6-way plug and a 7 way...not sure what they were towing...) Disconnect both, sorry no, de-jimmy-rigged. Scary. Look up at the lights damn.
Unplug the turn signal switch (tip from another TRS post) and the lights went off. Replaced the switch. Nope.
Decided I would take all the hot leads off the solenoid, except for the battery positive, and started putting them on 1 by 1 with the system hot.
And voila! Found one little gray wire that was connected and BAM the brake lights come on and off when I take it off. So...Truck starts and runs all lights work turns brakes dash everything.
Now my question..... What is that wire and where TF is supposed to go and wtf is it supposed to do? and if you can tell me why in the hell it makes the brake lights stay on that would be cool too...

 

[ericbphoto]

Ok. First if all, you’re talking about the starter relay. The starter solenoid is normally built into the starter these days.

With the gray wire disconnected, do the brake lights work the way they should? Does the gray wire look like a factory wire or like something a previous owner added?

 

[BadMonkeyRacing]

Yes it looks factory yes everything works as it should.