im having issues tracking down a dash back lighting issue. all the bulbs were burned out, so i was thinking it was just that, but in rotating the dimmer switch (a brand new one) it arced from the wire to the copper lever that is actuated by the dimmer rotating. i checked the 2nd to last pin on the angled 6 pin connector that connects to the gauge pod with my ohm meter and it is shorted to ground. im guessing thats why the dimmer switch arced like that. im probably going to rip the entire dash off to try and trace the wiring to make it 100%, but i was wondering if anyone here has had to repair an issue like this before on their first gen? all the other lights work except the dome light, but i have not checked to see if it was blown or not. also, there is a custom door switch on the drivers side, that when i hook up the center dash light, i can press that door switch and it only slightly dims that center light. does anyone have a viewable passenger compartment wiring diagram for an 89 w250 cummins?

 

This what you are looking for?

 

went and bought a manual with all the wiring diagrams then went hunting. turned out it was just a bad radio installation! they connected the orange wire that powers the dash backlighting, DIRECTLY to ground! its all working now, just waiting for the shift indicator to arrive so i can put it all back together.

 

They make VOM's and buglights for figuring things like this out. Connecting the dash lights wire to ground sounds typical for somebody who hasn't a clue about how to use either.

Edwin