Running a light off of the Rear Defroster?

88 4.0 5spd --- I took my rear defroster off my window, and but I kept the hot lead going to it. I have provisions to mount a rear 6" 55w light to my rear bumper and was seeing what you guys think about this. Is there a relay for the defroster? Is it heavy gauge wire the whole way through? I know there is heavy gauge going to it for as far as I can see, but I was seeing if it was all heavy gauge and could support a light?

The wire is thick gage all the way to the relay, but I believe there is a timer controlling the relay. So your light may turn off after some amount of time unless you disable it somehow. The relay for the defroster should be under the dash just beneath the switch for the defroster.

X2 on the timer, might be ok for a back up light though since it's unlikely you'll need to leave it on for any long periods of time.

Any idea how Long the timer is?

10 minutes according to the manual.