Classic/Antique Car Repair: 1972 Triumph TR6 fuel gage, voltage stabilizer, alligator clip

Question
Two questions please:
1. The fuel gage on my 72 TR6 does not work. Here's what I've done so far.
- checked fuse (good)
- checked wires connections at fuel sending unit (good)
- checked wires at sending unit for 12v (good)
- when using a simple tester (alligator clip with pointer type) and grounding with alligator clip and then pressing pointer to wire connection, the gage goes to full, the tester bulb lights up, but then starts blinking like a turn signal indicator. All other electricals work properly.
2. How does the head and parking lights suppose to operate. My steering column switch (right side) when pulled down brings on the parking lights and high beams and when pulled back also brings on the high beams. A foot controlled dimmer switch then will operate high/low control but I have no switch to operate parking lights only. Is this the correct design?
Thanks, Robert

Answer
Hi Robert,
The test light test you did indicates the gauge is OK, but I can't tell anything by your test. The TR-6 used a "voltage stabilizer" to power up the fuel gauge and the temp gauge which dropped the gauge voltage to 10v to the gauges. The tank sending unit varies the amount of ground of the gauge. So does the temp gauge use a sending unit on the engine to vary the ground to the temp gauge. The test should be as follows, if the temp gauge is working normal than the voltage stabilizer is OK.
Determine which side of the gauge is power, Disconnect the tank side of the gauge. Then with the key on, ground the tank side of the gauge. “No tank side connected” should get a deflection of the needle either "Full" or "Empty" then “ground the tank side” should get an opposite needle deflection. The only other option of gauges were that some had a "Low Fuel Warning Light" which would have a third connection on the gauge, in which case look at the color of the wires to see if there is a red with a white tracer on it and that should be the light wire.
As for the Switch positions, I thought the switch had a three position switch.” Off, Park & headlights" I am working from memory on that so I will check with a friend who has several TR-6s and get back to you.
You need a wiring diagram to work on the electrics. Haynes is usually good however; Haynes diagram looks OK except the index of their diagrams for the TR-6 is messed up. The Clymer manual has it corrected. If you can't come up with one let me know and I will E-mail you a diagram.

I hope this helps you, let me know.

HMF