I found this wire, while I was looking through my bay of the 89 roc. It was not connected to anything. I looked at my friend 90' formula and it had it the same way but grouped into a jacket with more wires. The wire is located on the passanger side, rides along the firewall and connects to another wire in middle of firewall sorta.

 

do you have a picture of it in the car?

 

Underhood light wiring harness. The flat part of the harness with the 2 plastic "push tabs" sticking out of it connects to a couple of holes on the main support link of the pass. side hood hinge and contains some sort of tilt-sensing device within the harness itself to turn on the underhood light when you open the hood and the hood hinge link tilts up from horizontal.

The single small brown connector goes to the underhood light, the two red ones on the other end I just don't know- I'm doing this from years-old memory. I'm sure somebody else could help you out with that.

They DO look important, though. I guarantee at least 2 things about them:

1. They connect to a full-time power source (battery or alternator, ultimately). Obviously, the underhood light needs power even if the ignition isn't turned on.

2. They carry some serious amperage to something- those are some BEEFY wires.