any chevy workshop will have wiring diagram and will usually photocopy it for you
try Autozones website
You can find the wiring diagrams for a Chevy Celebrity in either a factory service manual or either a Chilton or Haynes manual.
You can find the wiring diagram for a 1990 Datsun-21 pickup in several places. Check the vehicle's service manual, which often contains detailed wiring diagrams. Additionally, online forums dedicated to Datsun or Nissan vehicles, as well as websites like eBay or Amazon for repair manuals, may have the information. Lastly, automotive repair websites like Haynes or Chilton may offer wiring diagrams for purchase or access.
Autozone's website has free electric wiring diagrams
It will have to be of a 88-95 Chevy i believe.
The bed size is 6.5' of a dimension of 78x9x5 would fit a Chevy 1990 pickup.
If the bed was pulled off to repaint, they probably crossed the wiring, at the rear of the bed...
radio 1990 isuzu pickup
The diagrams for the wiring of the ignition switch on a 1990 Ford Mustang 5.0 can be found on a website called Sbf Tech. Many of the other wiring diagrams for the 5.0 can be found there also.
In the truck!
http://www.suzukiinfo.com/sierra/ It has all the manuals and wiring diagrams
Look on dsmtuners, or dsmtalk
I believe it is a 4*6