instrument cluster voltage limiter

If you do the 7805 conversion, you should know that your gas and temp gauges will probably give low readings. That was causing me lots of confusion with my gas gauge. It was like my gas tank had shrunk. When the gauge read empty, I would fill the tank - but it would only take about 11 gallons or so.:dontknow: And I was only getting about 160 miles from a 'full' tank.

RedFish's reply explained what was happening.:thumbup: RedFish is officially 'The Man'!:notworth:

These gauges were originally designed for 6v systems, but with the 7805 mod, you are only giving them 5v. That's a 16% difference!

If the engineers who designed the gauges assumed the automotive electrical systems ran on a higher voltage (like 6.3v) and designed them accordingly, the difference will be even more. In my experience, electrical systems normally run a little higher than battery voltage.

I really like making little circuits like this 7805 one, because electronics is my business. But I've decided to bite the $50 bullet and buy one of the limiters from RT Engineering. It looks like a well-designed unit, and it won't stick on 12v like the original one did a few years ago and destroy my gauges. Replacing them was an expensive and frustrating scavenger hunt that I don't want to repeat.

I also don't want inaccurate gauges to be another of the quirks about the Dart that I have to think about. There are already more than enough! :)

It's a relief to finally know what was going on, but I'm a little disappointed that none of the sites giving the instructions for the project didn't mention this problem.

If my logic is wrong, please let me know. Sorry about the long post...