Always disconnect and isolate the battery negative cable when making connections to the truck wiring.
Size the wires to the load and be sure to use a source protected by a fuse of appropriate size to protect the wires.
Secure the wiring to prevent contact with hot and/or moving engine parts.
Use caution when drilling to avoid unplanned ventilation of the hood.
This will vary depending on the type of light you choose and how you install it. I used:
Drill motor and bits
Underhood light assembly
Hereís an inexpensive and useful item you can pick up the next time youíre at the salvage yard: an underhood light. There are many styles that will work from many different vehicles. I selected this one from a Probe because it uses a 2-wire harness and takes the same bulb as a Ranger cargo box light.
The beauty of these lights is that they have a built-in mercury switch. When properly positioned, the light will come on only when the hood is open. Be sure to make a diagram of how the light assembly is positioned in the donor vehicle. This will help when you start looking for appropriate mounting locations in the Ranger.
Mount it, wire to a fused constant hot and ground, test and youíre done!
Cost? Mine was $5.00 including bracket and extension harness w/push pins and connector.
(Note: some underhood lights rely on case ground through their mounting fasteners and have only a single positive wire hookup. These are meant to be mounted to a conductive hood material like steel or aluminum. They won't work when installed on the underside of a composite Ranger hood unless you run an additional wire from the case to chassis ground. Composite hoods are found on 4x4ís and Edges from 2001~2003 and a few very early 2004ís)
Here is the finished light. It doesn't look very impressive photographed in daylight but it casts a useful glow over the entire engine compartment after dark.
One of my favorite cheap mods!
This is GMís retractable trouble light. It does not illuminate automatically when you open the hood but can come in very handy nonetheless. The lamp has a magnetic base and a 20-foot retractable cord - useful anywhere around the truck where there is steel or iron for the magnetic base.
If you get lucky, you might find one at a boneyard, usually on high-end GM pickups, Suburbans and cars from a few years ago. They are also available new online for about $50.
GM trouble light online