gauge problem

steveh2 · Jan 7, 2017

I have a Allis Chalmers D-21. all the gauges on the dash do not work. The tach is OK. I would like to get the fuel gauge to read. There is about a 4 foot piece of wire missing. Can I splice in a piece of 16 gauge lighting wire or must it be a special wire with out splices?
Thanks for the help
Steve

old · Jan 7, 2017

Most any wire will work just fine for that since the fuel gauge works by way of a rheostat that as the tank goes down in fuel the rheostat changed Resistance to ground to give a different reading. I'm not sure which way ti works on that tractor but on a Chev pickup up lack of a ground makes it read over full

Steve@Advance · Jan 7, 2017

You say all the gauges don't work...

Obviously the fuel gauge is electric. If you are sure where the missing wire goes, go ahead and splice it back in. If it is the fuel gauge sender wire, any wire will work, it was probably 16ga originally.

But there may be another problem since none of the other gauges are working.

There are 2 kinds of gauges, electric(like the fuel gauge), and mechanical gauges.

Mechanical gauges do not rely on the electric system. They are connected by means of a capillary tube for temperature, or a pressure line for oil pressure.

But electric gauges need power supplied from the ignition switch, and a chassis ground. Usually the gauges(if all electric)will share a common power source, typically a fused circuit from the ignition switch.

So, if replacing the missing wire does not fix the fuel gauge, look for a blown fuse, or another broken wire to the other gauges.
Typical gauge wiring

gauge problem

steveh2

New User

old

Well-known Member

Steve@Advance

Well-known Member

Similar threads