1970 SPL Directionals, Fuel Gauge not Working

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1970 SPL Directionals, Fuel Gauge not Working

Post by Kurt »

I have had intermittent loss of the gauges and directional (sometimes brake lights?). It always seemed to be a plug under the dash required some wiggling. I haven't found any loose plugs. Prior to my departure to Solvang this year they did their non-functioning thing again. Clock is powered, Flashers work. Brake lights function. Off I went.

Solvang morning trip was foggy, damp and cool. So I had wipers, heat and headlights on. Close to the 246 exit, Pumpkin lost power. Dead battery. Dang!

My diagnostics determined the alternator was not producing excess of 12V. Assumed the alternator was bad. I decided to do a 3-wire w/internal regulator, driver side to right side conversion so I could upgrade headlights in the future. Purchased the kit from Jim Tyler, Datsun Restoration Products. Thanks Jim! Nice kit! Not as straight forward as I would have liked, but I got through it. When I was done and new alternator is reading same as battery voltage, further testing and discussion finds the regulator may not be getting powered (still an assumption) with the key on. If so, may explain dead battery.

Two questions here;
Is there a common link/electrical plug(s) that effect the gauges and directionals? And the voltage regulator power? Do I need to pull connectors apart and plug back in for a possible better connection? If so, I'm assuming this was my problem all along including the resulting dead battery.

Also, I have two wires, a Bk/Y and a Bk with bullet connectors I do not recall disconnecting them during the alternator removal. They appear on the drivers side at the area where the alternator wires are. There is a Y-junction. One direction are the alternator wires and plug. The other direction are these two wires. Schematics suggest a By-pass valve? This makes little sense to me. Pics attached. Not great clarity but kinda show the Y-junction and the bullet wires are as described Bk/Y and Bk. What do they connect to? I do not see visible mating connections anywhere.

Alt Wires.jpg
Wire Ends.jpg
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70 SPL311 (Pumpkin)
67 SRL311 00520

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Re: 1970 SPL Directionals, Fuel Gauge not Working

Post by JT68 »

Hi Kurt, I took a look at a 70 harness, and yes, the b/w " ign on" wire goes through a 6-pin multi-connector right after it goes through the firewall over by the clutch master. That wire powers up the regulator. If that wire is dead when the ignition is on, the system won't charge.

The yellow temp sender wire also goes through a different 3 pin connector in the same location. The quick test for it is to simply short the yellow wire to ground with the ignition on. That should peg the temperature gauge. If so, The gauge, wiring, and instrument voltage regulator are functioning.

Blinkers are probably not related to any of this unless the multi pin connectors behind the firewall are disintegrating.
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Re: 1970 SPL Directionals, Fuel Gauge not Working

Post by jrusso07 »

On the first question, I know all directions go through the flasher switch - dont think the gauges go through it.

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