Defi gauge wiring....12v constant?
 

I have my Defi blue racer gauges hooked up. I had the 12v constant wire hooked up to the horn. That was a funky place to put it because everytime I turned off the car, the horn would honk. So I undid that wire, and everything still works fine. The only wires I have hooked up are the switched ignition 12v, and the ground. Is it bad to only have these hooked up? Because it doesn't seem to affect it what so ever.

I don't think it will affect gauge operation while the car is on. But you should try to locate a constant 12v source for the other wire.

what other wires does it require? maybe a illumination dim wire? you can tap the wire coming from the ashtray for that. ohterwise those 3 wires are all you need

I don't think it requires the dim light, but it has one, it doesn't bother me that it's always fully lit. Any idea where I can tap a constant 12v?

check out the location I used in my water temp gauge install:

www.davidgeesaman.com

I used the same location in the fuse box for the switched power. For some reason it also has a wire for constant 12v.

That location is switched power. Not sure why you'd want full time power for gauges. You'll just drain your battery if there isn't additional switching installed.

I just provided that as a reliable non-dimmer location.

Dave

I used the 12V constant from the stereo loom, for the dimmer I used the wire for the glove box light. Works fine and dims properly.

if it's the Defi one with the control unit the constant is probably to hold the peak stuff etc in memory when the car is off. I doubt it'll use much power at all to do that.

These don't have the control unit, each gauge is a stand alone. I'm not sure why, but it has a wire for constant 12V power and one wire for switched ignition 12v power. I was asking in the original thread if anyone knows what the constant power is for and if it is necessary.

^ this is the 12v constant i use. daves writeup is the best :)

also.. 12v switchable w/dimmer i use from the ashtray like others of you

Do your gauges do any kind of needle sweep or beeping when you turn the ignition to on?

Some gauges have an "initiation sequence" and "termination sequence" which causes the needle to do some sort of sweep pattern when the car is turned on or off. If you do not connect the 12V+ constant, you will still see the "initiation sequence" but you will not see the "termination sequence" since cutting the ignition cuts all power to the gauge. If the gauge sees a change from 12V to 0V through the ignition and is seeing 12V from constant power, it will do its little dance and then shut off.

It's peanuts really, but for myself it bothers me not to be using a feature of something I paid for.

^He is right also the constant power is used on the self diognostic, full sweep constant means short 1/4 sweep failed signal or broken wire. Just use the ash tray wire its easy to get to.

I use the radio wiring, it has everything you need for wiring gauges in one place.
12v constant, 12v switched, ground and dash illumination.