I'm trying to install a water temp gauge on a 2005 monte 3.4l and i have everything i would need for the job except a clue where i should tap into the ignition system to wire this thing properly or a good place to tap power for the light in the gauge. This says the + post runs to the ignition switch but not where/what wire. Also, from looking at this again, there are red/black wires coming out for the lighting in the gauge that would need to be connected to the lighting circuit or other 12v source. Any advice/help in making this thing work properly would be greatly appreciated.

 

IF I remember correctly, an electric temp gauge should have three wires. Green one that goes on the sending unit, a red one for power to the gauge light and black for a chassis ground.

Hook ups for the green and black wire are pretty straight forward. If you hook the red wire to a switched power source like the radio power wire, the back light for the gauge will be on all the time.

I dont know off hand about the newer cars, but in the older GM cars a single gray wire used to go to the bulbs for the a/c controls\ash tray bulbs. I would tap the red wire from the aftermarket gauge into the gray wire so the gauge light would only be on when the headlights were on.

 

well i stopped reading those crap instructions that came with the gauge and hooked everything up and it works.....sorta. The gauge reads 220-250 at what should be normal operating range and i disconnected the factory temp sender to use that location but the fans constantly run, even after you turn the car off. I hooked the original back to hopefully take care of the fan issue and moved the aftermarket sender to the spot on the thermostat housing and now the temp stays up around 250ish when warmed up.