MM Jet Star 3 Super

[Walkinfuss]

Can use some more help. The original MM volt meter does not work. I replaced it with a new meter, however the new meter will not allow the engine to crank or star when I jump the starter. Tried a second new meter the same. Put the original meter back in and it starts every time, just no meter operation.

When I ohm the old meter out, its a complete circuit. The new meters are open? The new meters read the voltage when I turn the key, just will not allow the motor to turn over of start???

Tried reversing polarity with no success? Both are new Bosch gauges. Any ideas? Thanks
 

[ChrisQ]

The original gauge is an amp meter. Volt meter gauge is different. A volt gauge just measures voltage. Amp gauge measures the current flowing through it.
 

[Walkinfuss]

Thanks
 

[molinegb]

As with all gauges a difference potential is required for meter movement. More positive than negative or vice versa. Can easily be checked with a battery charger
or power supply.
 

[sms]

Ammeter is connected in series, voltmeter
is connected parallel.