Hello everyone. I’m running into an issue with my four-wheel-drive not engaging. I have the manual shifter ****. It will not lock into for low or four high. The little lights will not light up and four-wheel-drive will not engage. Can you guys please help me or give me any good tips? Any charts or diagrams for the vacuum system or anything else I should look at?

 

Have you checked the vacuum actuator in the engine bay? It seams to be a very common issue with those trucks. I believe it's on the right fender just behind the battery, and if so you can't miss it. Hope this helps.