I need a headlight switch wiring diagram for a 1990 Chevrolet C1500

ebay

Not much of a diagram, but here it is.

Haynes or Chilton manual.

Here is the diagrams. Please rate my help for fixya.

look at wiring on top of fuel tank at the connection- either ground rotted off or bare wires touching or a crushed connector

Without testing the electrical circuit's for the headlamps we'd only be guessing . Looking at wiring diagrams an testing the circuit's with a DMM - digital multi- meter is the way to find the problem , not just replacing part's . Sound's like you know nothing of automotive electrical system's ,an testing . Suggest you take your vehicle to a qualified repair shop.

For the 1990 Chevrolet C1500 454ci = 7.4L V8 = "ss" = "big block"

Click on the the following: direct, Free Link. It has the Serpentine Belt Diagram for the 7.4L (454ci).
I'm not sure what you want on the "wiring" part??

Let me know if this helped, or if you have the additional informations or questions. Feel Free to contact me at FixYa.com!

http://www.2carpros.com/car_repair_information/year/1990/make/chevrolet/model/pickup/1990_chevrolet_pickup_drive_belt_routing_diagram.htm

The Haynes repair manuals usuall have wiring diagrams in the back of book.Around $20.

Try this

top is park only
middle is stop turn and park
bottom is reverse