Does it fail safely?

[GPster]

In cleaning up one of the messes in this middle Jeep I installed some after-market (Harbor Freight cheap) gauges. I made a new circuit with #10 wire for the -60 0 +60 amperage gauge and wired it so everything except the starter went through it. Through all the carb and starting problems and a new battery the amp gauge worked as expected. Now it's not working at all. It doesn't show a drain when starting and doesn't show a charge. When it was installed you could tell by the gauge that the alternator needed a little blip on the throttle to excite the alternator to start charging  but then the charging rate never was above 20 amps. There doesn't appear to be any short because the battery is staying up and the gauge is not an open circuit because everything works and it's all wired through the amperage gauge. Are these gauges designed with a circuit in them as a bridge in case the gauge fails? The alternator appears to be the stock one for this Jeep ('80 CJ7) and it's output never has appeared to be over the capacity of the gauge. There's so much to work on that doesn't work that I don't want to start on something that almost works with-out an idea and it's raining. GPster

[enjenjo]

If it's a shunted ammeter, the circuit will still function if the ammeter goes bad.

[GPster]

Well, I bought this set of gauges because I wanted an oil pressure gauge when I first started that 4.3 V6 I saved. It was a special price of $12.00 for the set and I couldn't buy an oil pressure gauge and an instalation kit for that much. I put them in this project because I had them and they were paid for so I'm not out much. The instructions don't say anything about a shunt. I've probably got another gauge in my collection. I'll change it some dry day while I'm checking to see why the shifter doesn't give me Park or Reverse now. Maybe all of this is why there were big grab hooks on either end of this thing. GPster