auto meter gauge

[dart67]

I bought a temp gauge and wired it up 1 wire to 12v 1 wire to sending unit 1 wire to ground, the promblem is when I turn the headlights on, the gauge needle goes up half way (even without the engine running)I tried different 12v wires and it does the same thing.Is something wired wrong?
Thanks Mike

 

[69signetv8]

Are your wires (hard wired) into the guage at the back or did you wire it up? To me it sound like your wires are crossed and your guage is reading your voltage supply...

On the back of your guage ensure that wires are connected correctly, (I) is to 12V ignition on, (S) is to Temp unit and G ground.

If it's correctly wired....take it back.

 

[rumblefish360]

It's wired wrong or the gauge is messed up.
1 wire to 12 volt source.
1 wire to ground.
1 wire to switched 12 volt sorce for lights. Tap into light switch for this.
1 wire to sending unit.

 

[dart67]

Thanks guys,it seems that the ground wire wasn't grounded well.
Thanks Mike

 

[fishy68]

Definetly sounds like a grounding problem. Is the engine ground to the firewall in place? If not that can cause weird things to happen. How about the 10ga. ground wire from the battery to the fender. That also can cause weird things if not in place.

 

[dart67]

If I turn the key to acc should the guage read anything?
Thanks
Mike

 

[fishy68]

Depends on where you connected the positive wire at Mike. You should have connected it somewhere which only supplies voltage when the key is in the "run" position. If you connected the positive to the accessory position of the key switch circuit it will read while in the accessory position in addition to the run position.