Your truck has the "stripped down" front end.
1) yes, you can goto any wrecking yard and find the harness from any 81 - 87 four headlight truck. It separates at the bulkhead connection on the firewall. All you need to get the connector loose is a 3/8 deep well socket to get the bolt out in the center of the connector.
2) On a four headlight set up the upper two headlights are high beam and the lower two are low beam (technically dual beam, they stay on when the high beams are kicked on)
3) The low beam and the high beam are different part numbers depending on what brand of light bulb you go with.
4) I don't think you can get them in anything but halogen anymore.
5) As far as upgrades go you have a couple of options...
a) HID set up. but for a good set up that will set you back about 700.00 bucks. (no thanks)
b) you can buy after market housings that accept halogen style bulbs. (like most cars made after 1990)
c) you can stick with a good quality factory replacement.
When you go to a wrecking yard here is a list of the parts you will need from the donor truck for the conversion.............
A) Headlight wire harness (it does separate at the bulkhead so you do not need the whole engine compartment harness)
B) The headlight surrounds (the pieces that look as if they are part of the grill that go around the headlights)
C) The headlight buckets, screws, trim and springs. (what the physical headlight actually sits in that is attached to the core support.
D) Marker lights/turn signals that are located behind the grill.)
F) And since you are already there and you have to take them out with your parts anyways, Grab the bulbs.
I would not pay more than 40 or 50 bucks for everything and it is really a pretty simple conversion. And plus it looks hella better than the single bulb set up. Good luck.
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