72' cj5 problems

It runs and drives fine however there are some problems

The fuel gauge doesnt work and temp gauge doesnt work. I was thinking on just replacing the gauges but, was wondering if theres a test to see if its the gauges are working or there might be another problem.

Also, the jeep had some work done about 2 yrs ago and the headlights and alternator worked fine but, now they dont. The lights dont come on and the alternator doesnt charge. I replaced the alternator about 6 months ago same problem.
The connection at the alternator is hooked up right. I have a Chilton jeep manual but, it doesnt provide a wire harness layout. Im thinking that mechanic unhooked some wires somewhere. He is since out of business.

Any help is appreciated, thanks

 

There's a 1972 Jeep factory manual at http://trailforge.com/cms/index.php?option=com_content&task=view&id=24&Itemid=30

It will have your wiring diagrams. It should also contain info about how to test the gauges.

 

I'd check the grounds. Most of the time elelctrical gremilins show up it's a grounding issue.

 

The fuel gauge controls the voltage to the instruments.
Seems as if you need a new fuel gauge.

 

Here is an excellent diagnostics page for the gauge cluster

http://www.luanjp.com/images/Mod/Electrical/CJSpeedometerGaugeQuickTest.htm