I have a clock replacing gauge house with autometer boost, egt, and oil pres. I have a pretty good idea on how to connect each gauge to the engine. The question I do have is how to power the 3 gauges. I read this very helpful tutorial on tapping into the clock harness: http://www.scoobymods.com/forums/showthread.php?t=3005
and he uses all the sockets in the clock harness to power his greddy gauges:
BAT = Red wires (constant power)
ACC = Orange wires (switched power)
LIG = White wires (illumination)
GND = Black wires (ground)
Here is a picture of my gauges. Which wires do I hook up to what clock harness sockets to properly power my gauges? All the lower black and white wires are joined together to make a clean connection, and the top red and black wires are connected to make 1 red and 1 black wire. FYI boost is left, oil middle, egt right. Please refer to the pictures in the link to help me understand your instructions.
http://i1.tinypic.com/o7qf4x.jpg

Not sure why they used the constant +12V...

If I had to guess, I would say black is ground (should be a black wire), red is switched +12V (ACC) (should be a yellow wire with a green stripe), and white is the fixed illumination lead (should be pink with a blue stripe or violet, depending on where you grab it) - if they are mechanical gauges and you want the lights to dim, instead of running the black wire which is next to the white wires (the ones which connect to the lights) to ground, run it to the other lead from the illumination circuit (not at the clock housing, but you can grab it from the radio housing - it will be orange with a white stripe)

Don't grab the constant +12V (the BAT lead - should be a blue wire with a red stripe) - you don't need the gauges powered when the car isn't running, and all it will do is drain the battery.

Thanks for your response, I'm still a little confused. You said the black is probably the ground. Do you mean the top 2 black wires or the bottom 3 black wires? I don't care to dim the lights. The black grounds (2 or 3? wires) plug into "GND", red wires into "ACC", White wires into "LIG" and the other set of black (2 or 3?) wires plugs into? I will make note to plug nothing into "BAT" since that power stays on all the time.

In most cars, the illumination circuit has one fixed lead (generally ground) and one variable lead (goes from 0 to +12V) - so in most cars, the ground you use for the electronics is the same one you use for the illumination circuit.

Sadly, the Subaru illumination circuit doesn't worth that way - rather than have the fixed lead be the low lead (ground), they have the fixed lead as the high lead (12V) and vary the other lead (0 to -12V) - so if you want your lights to always be at full brightness for the gauge, you grab the fixed lead (the violet one) and ground - and when you turn on the interior lights, the gauge bulbs see 12V and are full-bright. If you want them to dim, you grab both leads from the illumination circuit (the violet one and the orange/white one) and then when you turn on the lights, the gauge light is at whatever the dimmer is set at. If you have an electronic gauge, you usually can't do that as the grounds are interconnected within th gauge, so unless you build a circuit to work around the problem, you gauge will always be at 100% bright.

Looking at the gauges, the leftmost one in the pic is the boost gauge, and it's mechanical - the needle responds to the pressure differential between atmospheric pressure and whatever is in the tube. The other two gauges look to be powered, but it appears that the light is discrete from the rest of the electronics (you should check - use a multimeter and check the resistance between the upper and lower grounds - should be off the chart), so you could hook them up with the illumination circuit and have them dim properly.

In any event - the top grounds (2) need to go to chassis ground somewhere. The bottom 3 can either go to chassis ground or the second part of the illumination circuit.

I have really bad visualization skills when it comes to electrics and things I haven't yet tried. You say top 2 black and bottom 3 black wires need to go to a Chassis ground. Can I run tap all 3 into the clock harness GND or do I physically have to run it to the car chassis? And before I cut into anything I want to confirm that the red wires into "ACC", White wires into "LIG"?

Another electrical noob question: If unplugging the harness breaks the circuit between the clock and electricity, wouldn't unplugging it and tapping wires into it still not complete the circuit? Or the ground wires complete the circuit?

Ok - in the picture you have two black wires on the top (those are for the center and right hand side gauges in the picture) and two red leads on the top (those are also for those two gauges) - connect the black leads to the black lead in the clock harness (GND). Connect the red leads to the yellow wire with the green stripe in the clock harness (ACC).

For the lower wires, there are three black and three white

For the white ones, connect them to the violet wire in the clock harness (LIG) then for the black wires, you have two options - if you want the gauges to come on at full brightness all the time, connect the black leads to the ground lead in the clock harness (GND). If you want to be able to control the lights with the dimmer, you need to connect the black leads to the other half of the illumination circuit which you can get from the harness for the radio - it's the orange lead with a white stripe (there is actually a little sub-harness from the radio harness for the OEM boost gauge - it has both the violet lead and the orange one with a white stripe)

For the ground leads, you could also make your own chassis ground instead of grabbing the one in the clock harness (just electrically connect the wire to the car body), but since the clock harness is right there, and you are already splicing into it, you might as well use it for the ground

Thank you so much for clearing that up DrD. You've been a great help. I will try the install this weekend and post up some final pics.

I need this thread later...

I need this thread later...

Then bookmark it and post in it later, instead of bumping it now since it's a year old. ;)

Sorry. Will do next time.

Well since this threads back it should be obvious but still stressed to make proper electrical connections. I used pinch connectors on the majority of this install and had to sort through my work twice to fix bad connections.