After market fuel gauge

[littleg]

I'm installing new Auto Meter gauges in my 69 F100. I've read several post about the fuel gauge but I'm still confused about the voltage regulator. Is it needed or not? Can I run 12V to the gauge and connect the sending unit or run 12V to the regulator and then connect it's output to the gauge and connect the sending to it's normal "S" terminal ? Sounds like many have run into this problem.

Gene

[Montana71-F100]

Since you haven't received any responses I'll give a stab at your question. The original gauges use the 5 volt voltage regulator because when the standard voltage switched from 6 volts to 12 volts they still had a lot of gauges that used the 6 volt system that they wanted to use. It switches from on to off constantly to average 5 volts. If you connect analog multimeter to the sender the needle will pulse. The sending unit in the tank works like the float that's inside your toilet and is connected to a rheostat. When the tank is full the gauge gets the full 5 volts. When it's half full the gauge gets 1/2 of that. I doubt if 12 volts would harm the sending unit. My guess is that since you have an aftermarket gauge it could be made to use 12 volts. You should look at the information that came with your gauge or contact the company that made it to find out for sure. If it uses 12 volts I can't see why you couldn't just bypass the regulator. When the tank is full the rheostat would give the gauge 12 volts instead of 5.

This is just an educated guess.

Good luck

[littleg]

Thanks for the response.

This is what I was guessing. My whole concern started when I worked for several hours trying to get the gauge to operate. As a last resort and with lots of frustration, I checked the box and realized they had sent me the wrong gauge. Yep it's hard to get a 0-30 ohm unit to work on a 70-10 ohm sender.

I figured I'd post the question while I was waiting on the correct model.

[Calfdemon]

I installed AutoMeter gauges and just bypassed the voltage regulator all together. As long as you have the right fuel gauge, it will work fine.