86 Suburban dash lights

1986 Suburban dash lights. The problem is that the lights illuminating the oil pressure, ammeter and temp guage work but those for the speedometer and gas guage do not. Not a pretty thing when cruising along at night.....
According to the Chiltons wiring diagram the ones that do not work are the "Panel Lights" and they are fed from a "Panel light fuse". Unfortunately ther does not appear to be a Panel light fuse in the fuse block and the instrument light fuse (which feeds the part does work) checks out good. Before I tear apart the wiring harness is there a common failure mode/point I should look at here?:banghead:

Try replacing the bulbs before you go tearing apart the fuse block. The instrument panel comes off easy enough.

Replaced all the bulbs, pulled the dash apart, ohmed out the printed circuit on the back of the dash, ohmed all of the bulb holders too still nothing on the four lights that illuminate the speedo and gas guage.
Had a new headlight switch but swapping it in made no difference.

I had an intermittent bulb on my 86 Suburban when I got it. You hit a bump and it would go out, hit another bump and it would come back on. I took the cluster out and checked all the bulbs, sockets, ohmed out all the traces on the copper clad board and didn't find anything. I took some 800 grit sandpaper and lightly sanded each connection where the bulb socket plugged into the copper clad bd. I also hit the contacts on each bulb sockets and bent them out a little so they fit tighter and it fixed it. I'm pretty sure all the panel lights are all fed off one fuse. Chiltons's aren't the best source for wiring diagrams. Don't get too aggressive with the sandpaper, those copper traces aren't very thick. Good luck.

Well I finally had to cry uncle as I needed the truck on the road. I was not successful in getting the stock lights to work and just didn't have enough information (in the way of a decent wiring diagram), patience to physically trace out all the wires or time. Anyway my work around was to go to Schucks and purchase a trailer marker light with 4 leds which I then disassembled and mounted the socket and board behind the speedo/gas gauge, ran the wires out the back of the cluster housing and wired them into the headlight switch so no I once again have dash lights. Not quite as bright as the originals but workable.