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.
Autozone's website has free electric wiring diagrams
It will have to be of a 88-95 Chevy i believe.
radio 1990 isuzu pickup
The bed size is 6.5' of a dimension of 78x9x5 would fit a Chevy 1990 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.
If the bed was pulled off to repaint, they probably crossed the wiring, at the rear of the bed...
Look on dsmtuners, or dsmtalk
http://www.suzukiinfo.com/sierra/ It has all the manuals and wiring diagrams
In the truck!
A wiring diagram for a 1990 GMC 2500 4x4 can be found in the car's owner's manual. You can also find wiring diagrams at auto part stores.
http://www.alldatadiy.com/