I am adding an air/fuel mixture gauge to help fine tune my '81 308 GTSi. I need to install an 02 sensor in the exhaust. I have had a bung welded into a good spot, and now I need to find a 12v source for the heater element in the sensor. It needs to be 12 volts when the engine is running only. The instructions for the kit say not to take power off the coil source because it can cause ignition problems. My question is this: Is there a good source of 12 volt when running power under the bonnet, or do I need to run the wiring all the way up to the fuse box? Also, does anyone have a suggestion on the best way to run the wires to the gauge on the dash? I was thinking of going under the car to the front hood, then down through the hole that the heater controls use and into the console. I don't know if there is a better way.
The AAV and WUR both get +12V when the Fuel Pump is running, which is perhaps better than just 'Run' voltage. It is a convenient connection. Your kit may have additional protection but that circuit receives adequate current protection by the #3 fuse. That fuse is always at +12V but relay switched by ignition switch and air flow sensor. Both AAV and WUR wires should be brown.
