Fuel guage?

seajay-1seajay-1 Posts: 4,736 Captain
I can hook up the main leads for my fuse panel to the cranking battery and the guage works. If I move them to my house battery it will not. Every thing else has power. What am I missing?

Replies

  • rehartlinerehartline Posts: 779 Officer
    Sounds like the grounds between the batteries are not tied together or there is some sort of blocking diode between them. Do you have a test meter?
  • seajay-1seajay-1 Posts: 4,736 Captain
    These are 2 independent batteries. Yes have a meter.
  • rehartlinerehartline Posts: 779 Officer
    But the black lead on the negative post of one of the batteries. Put the red on the positive post of one and then the other, keeping the black lead on the original negative post. You might need to use a piece of wire to extend the lead for length. See if you see something around 12 volts on both. If not the ground or negative side of the batteries is not tied together. I you do, then something else is the issue. Is there anything odd about your electrical system like 2 pole battery switches or a alternator dual charging module?
  • seajay-1seajay-1 Posts: 4,736 Captain
    No battery switch/charger yet. The 2 Batt. are not connected. The Start battery just has the 2 leads going to motor. From factory harness there is a + and - leads. Maybe the gauge is somehow getting a hot feed from the switch? If so how?
  • rehartlinerehartline Posts: 779 Officer
    Of the ground (negative) of the two batteries are not connected you won't get a circuit when you move the positive lead connection (in this case the hot wire for the fuel gauge) from one to the other. You can connect the two negative terminals together without causing any issues. Just don't jump the positive terminals together unless you do it with a battery switch. If you plan on putting in a battery switch at some point the negative jumper must be sized to the size of your engine's starting cable. Anything smaller could melt when you combined or switched batteries and tried to start the motor.
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