Location of Gauge Ground - 1971 1110

[dparkusa]

I'm trying to locate where the gauges are grounded for my 1971 1110. Neither the engine temp/oil pressure or the fuel level gauges are responding or lighting up, and I've checked that the fuses are good. Next place I'm headed is the ground. I see that those two gauges are grounded separately via their own ground (as circled in the attached schematic), but I can't locate where that is behind the dash or in the engine bay. I'd like to avoid tearing apart the wiring harness and I've already done a lot of contortions trying to look under the dash. Any help would be greatly appreciated!

[Scoutboy74]

There are a number of possible causes for what you're not seeing from your instruments. You'll need to take the front face plate off so you can access the individual gauge clusters for closer inspection. The connector pins that are swaged into the printed circuit boards are extremely fragile and thus are well known trouble spots. You have to be very careful about removing the plastic gang connector from the pins. The stamped steel nuts that secure the gauges to the PCB's can work loose or develop corrosion underneath. Speaking of corrosion, if the copper traces in the PCB's appear tarnished, use a pencil eraser to clean up the traces. Don't use anything abrasive there. One or more of the specific senders for each non-functional gauge could have failed, as could the wires or terminations running between the senders and the gauges. There's also the firewall bulkhead connectors to examine and clean as well. I think you're getting the point by now that there really isn't a quick and easy answer. Solving these problems takes a persistent, methodical, logical, and thorough approach. Grounds are an important piece, but they're not the only piece. No associated stone can be left un-turned.
As for the gauge lighting, again, multiple possibilities ranging from a burned out bulb, to a damaged bulb holder, to corroded contacts, and so on. Study that schematic until your eyes bleed.

[dparkusa]

Found the ground, and as you say it isn't an easy fix. I'm going through it methodically as time permits. My eyes are a bleedin......