I never did get an answer to that question, but I think it is for the chime to let you know your key is in ignition. I never got my truck to run and spent hundreds of $ and had 2 locksmiths work on it all after charging the battery, it never ran again.

I sold the truck as is and bought a 2003 ranger.

PATS is the stoopedest thing ever put on a vehicle.

Best of luck

jake

 

Could be the "key in ignition" sensor wire, it would sound the warning chime if key was in ignition when drivers door was opened, so you don't lock keys in the vehicle
Its a 1 wire sensor, its Grounded when key is inserted into the ignition cylinder