Another Gmt900 Underhood Lighting Project..

old-chevy-dude · January 17, 2011

i know a lot of people think this is foolish, but I like having an under hood lamp, and not having to fumble for a flash light if I am on the side of the road. in addition I always liked the retractable lamp feature in my 1999 Silvy..

I ordered a replacement LED lamp for the fixutre (bulb number is 631 with 1156 base if anyone needs to know: http://www.superbrightleds.com/cgi-bin/sto...F67.htm#photos)

I bought a set of mercury switches on ebay for $20 (for 5) I intend on using one for the tailgate to auto enable the cargo lamps when I drop the tailgate.. I might find a use for the others, if not I have spares..

I found that position 65 in the underhood power distribution block is for Electric Running Boards and is un-used and not connected in my Avalanche as this is not an option for the AV's, so the input side of the circuit is live, but the output side has no wiring..

using a female spade connector:

I inserted it into the empty slot under the fuse block, thus giving me a fusable link for power. hooking the ground to the mercury switch and attaching it to the OEM hood ground strap and location allows for the lamp to turn off when the hood is closed, and keeps everything looking as OEM as possible, with no nasty external fuses, or mismatched fuse types.

in this picture it is the raised 20amp (which has since been replaced with the correct length fuse, but the extended is all I had on hand when I wired it up)

I centered the lamp on the hood and used some self tapping screws to secure it:

here is the mercury switch, and the yellow wire is the power that runs up under the hood shield (and is incased in some wire loom):

and since it is retractable with a 20 foot cord it reaches to the rear wheels in the advent I need a light for changing a tire (and the unit has a magnet on the back so it will stick to the body of the truck)

as you can see, at about 45 degrees the lamp turns off: