'81 K10 instrument cluster / fuel tanks dash switch

[Frankenstien]

I decided to sort out a few dashboard issues with this truck today but I think I need a little help to finish up.
This Canadian-built Chevy has the full Silverado gauge package, cruise control (still works!), auto trans and dual fuel tanks (controlled by a flush-mounted dash switch, just left of the ashtray).
The speedo cable/head has this really annoying squeak (worse in cold winter conditions), the instr. backlighting is out on the left side, the little braided wire connecting the column shifter to the PRND21 indicator is broken and my R fuel tank gauge indication always goes way beyond F, no matter what the actual R tank fuel level. The L gauge indication is fine, as is the actual fuel line switching for both tanks.
So, I have the means to inject molybdenum disulphide lubricant into the disconnected speedo cable but am wondering if my squeak resides in the speedo head itself - is it possible to sparingly lubricate the speedo head mechanism?
As for the instr. b/l (and fuel gauge?) issue(s), I can see that GM's adhesive film electrical circuitry approach to wiring the instr. cluster doesn't stand up well to abuse ... mine has lots of damage from previous owners attempts to change bulbs and/or ?
Just in case the visible breaks in the copper traces at the fuel gauge don't explain the R fuel tank ind. issue, how does one extract the dash switch for testing w/o destroying it?
And, although I haven't asked my GM parts dude about the the little braided wire connecting the column shifter to the PRND21 indicator, I seriously doubt GM would have this separately available - does anyone know of an outside supplier or retro-repair option for this thing?
Finally, I found that removal of the instr. cluster was a bit of a bear. Either it is a poor design, or, somehow, someone managed to inappropriately force the lower left edge of the cluster behind the sheet metal of the dash - getting it out involved pushing up on the dash pad harder than I would have liked. Should the instr. cluster lower left edge live inside or outside the sheet metal of the dash?
Thanks for any help I can get ... FFF

[72 CustomCamper]

It's easier to remove the dash pad before the dash cluster. The cable for the gear selector can be bought through Classic Parts of America http://www.classicparts.com/1973-83-...info/91%2D472/. The issue with the gas gauge on the one tank is more than likely a broken ground wire at the sending unit on top of that tank...


Chuck

[Frankenstien]

Hey Chuck ... thanks for your help ... that little cable is a real good find ... thanks for that one.
What does it take to remove the dash pad? Seems like it's glued in or something.
I found 'Fuel Gauge Trouble Shooting' 'by Jolly Goodfellow with help from Gregory Smith.'
That should help me isolate the fuel gauge issue (I'll start at the R tank sender) ... have you had the fuel tanks selector switch out of the dash?
What's holding that sucker in there?
FFF

[Prong]

If your left tank reads fine, I'd bet on a bad ground for the right hand sender. Look on the inside of the frame rail around the tank area and you should see the ground wire where it bolts on the frame. Clean it up and see what happens.

[Frankenstien]

Hey Prong ... thanks for helping out ... I will be crawling under there later today to see what's what with those R tank sender wires.

Can anyone comment further about lubricating the speedo head itself ...

or how the instr. cluster is supposed to fit the sheet metal dash (lower left edge inside or outside the sheet metal?) ... and how to remove the dash pad so I can get at things easier?

or how that dash fuel tanks selector switch is held in the dash so I can get it out without breaking it?

Thanks guys ... FFF

[72 CustomCamper]

The dash pad has 4 7mm bolts above the glove box door, 1 phillips screw by the pass side door jam. You have to remove the dash bezel first, If the truck has AC reach up in the glove box onthe right side and remove the heater duct hose going to the dash vent outlet. Then pull the pad towards the seat. It has 6 clips that hold the windshield side of the pad to the dash. The tank selector switch has 4 plastic fingers that hold it to the dash...


Chuck

[Frankenstien]

Right on Chuck ... thanks for the advice ... I do have A/C so I guess the dash pad removal is a little more trouble than I anticipated.

Do you recall if the instr. cluster left lower edge (just below fuel and water temp gauges) tucks in behind the sheet metal opening of the dash, or, should it sit in front of it (against it)?

And when you say the fuel tanks selector sw has four plastic fingers, what is the best way to force them aside (from the top, bottom, left or right) using what kind of a tool (credit card or ?)?

Thanks, FFF

[72 CustomCamper]

The cluster should tuck behind the metal. Onthe selector switch you should be able to reach your hand behind the dash and squeeze the little fingers in to remove the switch. I have a spare switch, after lunch I'll get you a pic of the back side of the switch...


Chuck

[Frankenstien]

Thanks Chuck ... a pic will sure help ... I've got big hands, the A/C ducting is kinda right there and the ashtay opening is walled off so, the more I understand about how it's designed, the less trouble it will (should) be.
FFF

[72 CustomCamper]

The only piece of duct that need to be removed is the flexible piece goint to the far right side vent. The hose is only about 8 inches long. Here are 2 pics of the back side of the switch. This is a GM replacement switch and only has 2 fingers. The big one is the top side of the switch.




Chuck

[Frankenstien]

Excellent pics ... you've been a big help Chuck ... thanks again for doing that ... now that I see it, I guess I'll carefully pull on the top of the switch while using a credit card ... after I exhaust my efforts testing continuity issues ... starting at the R side tank sender.
FFF