Where is the Data link 1986 Chevy pick up?

There's no standard "Data Link" connector in a 1986 Chevy pickup truck in the same way later models have OBD-II. 1986 trucks used a system of diagnostic connectors and techniques that varied depending on the specific engine and options. To find diagnostic information, you'll need to locate the:

* ALDL (Assembly Line Diagnostic Link) connector: This is the most likely place you'll find diagnostic information. Its location varied slightly depending on the truck's trim and options. Common locations include under the dash, near the steering column, or under the hood. A repair manual specific to your truck's year, model, and engine will show you the exact location.

* Other connectors: Depending on the specific systems (fuel injection, transmission, etc.), there might be other diagnostic connectors. Again, a repair manual is essential.

In short: You need a 1986 Chevy pickup truck repair manual to find the correct diagnostic connector(s). The manual will have diagrams and instructions on how to access diagnostic codes.