[Rich69shortfleet]

Weather finally returned to a semblance of sanity so I've had some chances to dig further into the issue. I checked the light at the lighter and the heater controls and found no issues. So, since the dash is all torn out and I have more ready access I pulled the fuse panel off the firewall. When I unbolted the harnesses in the engine compartment I did not find any issues at least not any that looked obvious.

When I pulled the fuse panel down I checked the continuity along the green wire at the headlight switch to the panel; all good. I also checked the continuity along the grey wire from the fuse panel to the cluster bulkhead; all good. Okay, if the wiring is okay, that pretty much leaves the fuse panel. The fuse clips looked clean but I scraped them anyway and still got a weak signal across the fuse clips. I then looked at where the green wire attaches to the fuse panel and it looked solid. The grey wire clips to the other end of the fuse so I pulled it loose. It looked 50 years old but not corroded but I cleaned it off and reseated the grey wire clip and lo and behold I was now getting a strong clear signal across the fuse.

So, I'm still not entirely sure where the restriction was but I suspect it was where the grey wire clipped onto the back side of the fuse panel and by removing it and reseating it I got a better connection. This would also explain why the problem persisted until I pulled the fuse panel down.

I still have to put it all back together but I did plug in the cluster and installed the dash lights with LED bulbs (which is why I started in on this odyssey in the first place) and they happen to look fantastic, very bright. They don't dim with the headlight switch, they are either on or off, but that's just fine with me. These trucks' dashlights have always been so dim even at the brightest setting I like the opportunity to brighten them up a little bit more. Given how the LED bulbs are built and how the fiber optic cable feeds light to the column shift indicator I don't know if the LEDs will properly illuminate the shift indicator but we'll see when I get it all together. I'll also need to buy a few more different kinds of bulbs to also LED the turnsignal indicators. I might as well do the glovebox lamp as well.