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Discussion Starter #1
After trying to fix my wiring gremlins all morning long, I can't seem to get anywhere (except creating or finding more problems) so after looking through most of the posts on these issues I seem to be more confused than ever....so I'll work on something else while hopefully you guys chime in with some suggestions. Background.... '67 RS with AAW wiring and aftermarket gauges (autometer) and mainly aftermarket/repro everything else (fuel tank, sending unit, etc). I just completed the car in the past month and after taking it for a spin I noticed the gas gauge was not functioning (sitting at empty). Disconnected the tan lead in the trunk and put an ohm meter on it....it read 44 ohms which is around a 1/2 tank which is close to what I would guess is in it. I then, by chance, checked the rear parking lights (with the lights on) and they did not function. I had earlier had a problem with the brake lights (that I fixed) so I rechecked the brake lights, emergency flashers, and turn signals and they all worked properly. I then noticed that I had the fuel line and license plate light swapped in the connector (they both plug into the rear harness side by side). I corrected this problem and then I checked to see if everything worked and now the fuel gauge is pegged (past full) and the parking lights still do not work. I checked the voltage across the fuse (with the fuse removed) for the parking light circuit and it showed 12VDC. Not sure where to go next. I also checked the ground on the fuel sending unit and it looked good. Sorry for the long post but hopefully someone can give me some ideas. So to summarize my current condition.... parking lights do not work and the fuel gauge is pegged....everything else looks normal.
 

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In the trunk disconnect the fuel guage tan wire. On the car side of the connector(not the tank side) Put a test light connected to ground , guage hould read about 1/2 tank. With this same connector derecrtly to ground it should read below empty. If it does all that repllace the sender in the tank. If not trace the problem towards the front. All this info and more is in the electrical sticky at the top of this forum.

Jeff
 

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You had the 2 wires crossed in the trunk. The light circuit was putting 12 volts to the sending unit which might have burnt it up. The 12 volts is at the gauge only. Now it shows that you are past full. Which means a bad ground at the sending unit or the sending unit is open.

Remove the tan wire from the sending unit in the trunk. Ground the tan wire that goes to the gauge ( not the wire going to the tank ). Turn your key on. If guage and wiring is good it should go to empty. Remove tan wire from ground and should go back past full.

If the above works like that then it is a bad ground or sending unit or connection on the sending unit.
 

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Discussion Starter #4
Mike,
You just beat me to the fuel sending unit problem.....I just dug up the instructions from Autometer and it definitely states not to accidently touch a 12vdc source to the sender terminal (which is exactly what I inadvertantly did by crossing the wires). I'll still make sure that the sending unit and it's ground is o.k..... I wouldn't be surprised if I have both problems (bad gauge and bad ground).
 

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Discussion Starter #5
Just grounded the tan wire from the gauge and the gauge did go back to empty but when I disconnected it the gauge still stayed at empty instead of going back past full. I guess the erratic operation of the gauge may mean that it is toasted.
 

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Discussion Starter #6
I just worked my way forward on the harness to the connector under the dash that connects the rear harness to the main harness and it looks like I have a good reading on the fuel wire (around 45 ohms) so it looks like it is definitely a smoked gauge. I also check voltage and continuity for the parking light circuit while I was at the connector. I had 12vdc at the connector under the dash but when I unhooked the line and checked the wire routed to the trunk for the parking lights it did not check out and it looks like the line has been broken somehow. That seems to explain that problem. So in the end it looks like a toasted fuel gauge and a broken parking light wire were the problems.
 
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