Power feed to gauges?

[84 chevy guy id]

Hi all, working on my 84 chevy 3/4 ton diesel (now a gasser). When I bought it the only gauges that worked were the speedo, and the volt meter. The other day the volt meter quit so I been checking out stuff on it to figure out whats going on. I took the cluster out and pulled the volt meter out and it tests fine. What I have found so far is that there is a pink wire with a black stripe that, after going over wiring diagrams on here, seems to feed voltage to all the gauges, and with a test meter on it only shows 4.5 volts but occasionally will jump up to 10 volts for a sec then goes back to 4.5 volts again. I have studied the 2 pages of instrument panel wiring diagrams on here and it looks like that circuit is numbered 39. It also shows a splice #39 with wires going several different locations. After pouring over these 2 pages of instrument panel diagrams, I cant find where the #39 circuit picks up its power from. I checked all my fuses and as far as the fuses go they are fine. I am thinking I have a bad connection somewhere, maybe where it picks up its power or that splice, wherever it might be. On page 1 of 2, in the lower right hand corner of the diagram, it shows 2 dotted lines that come from the #39 splice that are listed as #39 pnk/blk and they dead end at the bottom of the page and I cant see any place on page2 of 2 that might show them going to a power source.
 So, after reading this novel, my two questions are, does anybody know where the pnk/blk wire pick up its power from and where might that splice be located in the wiring harness so I can check it for a bad connection?

Thanks,
Mike

[bd]

Mike, I hope this helps you - at least some.  Ckt 39 (Pnk/Blk) is GM's standard circuit designation and color pop for the "fused ignition" circuit.  "Unfused ignition" (Ckt 3 - Pnk) runs from the ignition switch to the fuse block.  Ckt 39 begins life as Ckt 3 passes through the IGN fuse.  From the fuse block, Ckt 39 runs to a splice in the dash harness bundle, somewhere on the driver's side of the dash.

I suspect you have a poor or burned connection somewhere between the splice and the gauge socket.  Connection problems between the harness connector and PC board, and between the PC board and gauge are common.  Often times, gently cleaning the copper foil of the PC board is sufficient.  The shiny spring clips that make the connection between the PC board and the gauge can also be a problem due to tarnish and loss of spring tension.  Take a look in the Technical Pages for more detail on gauge troubleshooting.

When you take voltage measurements, be sure you have a good consistent ground connection for your meter.  However, you may find using a test light more reliable when checking for power problems, since a test light places a small current load on circuit connections.  Poor connections become more evident and less interpretive.