Electrical Question.. Do 40s have a Voltage Stabilizer for instrumentation?

[Rocky_LC]

My truck has been indicating low on my voltage gauge (10.9V, when I was used to seeing 12.9V), and my gas gauge , and temp gauge also seem to be reading low.

The battery seems fully charged (cranks strongly), although I should verify alternator performance, and do some quick tests to verify my voltage gauge matches alternator output voltage.

I know some little British cars use a voltage stabilizer for the instruments…. Just wondering if our trucks have something similar?

Thanks for the input…

Rocky

 

[charliemeyer007]

I think the amp meter shunts to 5 V for the fuel gauge on older ones my 72. Its covered in the manual and threads about rebuilding/adjusting gauges here abouts.

Mine have always been marginal. I installed a direct read oil pressure gauge, a big rear heater and an aux gas tank. The odometer is my fuel gauge of choice.

Check your battery with a good VOM, then the output of the alternator at a fast idle. Old rigs have old wires - corrosion can crawl under the wire insulation at connectors and cause a lot of resistance IE voltage drop. Clean, inspect, lube every connector is a good start.

 

[45Dougal]

What is your aftermarket voltage gauge connected to?
If its connected at the battery, then it is what it is. If its somewhere else then you could have some bad connection anywhere in between.
I'd start by checking the battery connections and fuse box.