Wiring Multiple Gauges (cleanly)

[eschlenz]

I will be rewiring my 3 A-pillar gauges, but want to do it right (clean install). Right now I'm tapped into the same 12V keyed source using those crimp splicers. I was never happy with that solution, and want a more professional one.

What I plan to do is splice into that 12V source once, and run the power to a barrier strip (or some other distribution/terminal box). That way I can just screw in new connections that need a keyed power source. My current 12V source is right behind the instrument cluster (can't remember which wire off the top of my head).

So here are my questions:

1) I'm sure my current 12V source is already fused. If I'm running, say, 4 gauges off that power source should I consider changing the size of the fuse? If so, what size?

2) One other solution I might go with is to power the gauges straight from the battery, using a relay that kicks in using the 12V keyed source. If I did that, what size fuse should I go with?

3) Finally, is there a formula, or rule of thumb for knowing what size fuses to use depending on the scenario?

Thanks in advance.

 

[revhead347]

Well, here's how I usually go about it. There are two wires you can use right off the back of the radio. One is the keyed power source from the ignition. You can use that one with an inline fuse. 3 amps is plenty, gauges barely use anything. The other is the dimmer wire that dims with the rest of the instrumentation, it's blue with a red stripe. Use that for the back lighting on the gauges. Then you can ground to anyone of those metal screws under the dash. That metal part of the dash is grounded to the body. I think you are being too enthusiastic with putting a bus in. Busses are commonly used, but honestly it just adds another piece of exposed metal that can corrode. It's better to make a little wire tree with solder and heat shrink. That seals up nicely in a way that doesn't allow much air in to corrode the metal. Most busses that you buy are aluminum, and they don't conduct electricity well at all if they get corroded. Don't go crazy with the electric wire gauge. 18 gauge is plenty thick enough. If you need extra wire, the best place to get it is Home Depot. Just buy the stranded wire from the bulk rack.

Kurt

 

[NinJa_FLiP]

all ive got to say is choose wisely where you draw your 12v ignition/keyed source.... i usually draw that power from the large 12v ignition wire thats in the main ignition switch harness.. another good option if you plan on needing more 12v sources in the future is to run the relay you mentioned off the battery or even using a 12ga amp power kit and put that into a distribution block and run the relay off that so your gauge lights will turn on and off with the other interior lights.. and yes the gauge of wire is important so dont guess on fuses, they can still fail and fry your wires.. then youll be in deep *****..

 

[cjrpony]

What I plan to do is splice into that 12V source once, and run the power to a barrier strip (or some other distribution/terminal box). That way I can just screw in new connections that need a keyed power source. My current 12V source is right behind the instrument cluster (can't remember which wire off the top of my head).

I did that with my gauges. I mounted the barrier strip to the metal frame of the dash right behind the panel under the steering wheel. That made it easy to access. I don't know about what size fuse to use (mine is hooked into the radio circuit at the fuse box) but I would hook them all up and then use a meter to see how much current they draw and select a fuse just slightly higher than that.

 

[blksn955.o]

I built a fuse panel of my own to power non-factory items.

I tapped into the vert power wire (I have a coupe), the vert switch power source that would go to the vert switch is installed and powered (but capped) on coupe models. It is a switched 12v source. I ran a line to the underhood fuse block to a relay, ground, line out (to the fuse panel), and switched (vert power source). The key on powers the relay and the power is sent from the underhood fuse panel to the stand alone fuse panel.

I have a 6 fuse panel.

1. line lock
2. n2o main power
3. n2o bottle warmer
4. Autometer electric gauge and tach power source
5. open
6. open

Now for the lights of the Autometer gauges I tapped into the dimmer switch as mentioned above (just tach and fuel press for now). I plan on moving to an all LED dash/gauge setup and will install the needed parts for a functional dimmer as the LED draw far less power than std bulbs. I want to do this sooner rather than later as I dont want the draw of my tach, water temp, oil pres, fuel press, and soon an n2o press light to cause any draw issues with the factory dimmer.

 

[eschlenz]

Thanks for all of the feedback guys. I ultimately went with a barrier strip that is tucked neatly into the A-Pillar. I now have a great central location for hooking up to ground, 12v keyed and 12v all the time now. Because the gauges aren't putting much additional load on the system, I'm just depending on the existing fuse for that line.

One note to those who hook up gauges in the future: I highly recommend using the bullet shaped connectors that snap together for your connections. It makes it much easier to get in there, take stuff apart, swap things around and reassemble.

I will take pics soon. I have to get back in there next weekend when I install my wideband.

Thanks again!!

 

[nmcgrawj]

Blksn955.0

I demand pics of said set up. Lol

 

[blksn955.o]

Blksn955.0

I demand pics of said set up. Lol

will do, after I swapped the 03 console in I am now playing with switch placement/new switches, when that is sorted out I plan to do a detailed pic of what wires to tap into and were I placed things. I am going to cut out the power port in the bezel and the bulk behind it to mount my tweecer knob to. Then put the line lock and bottle warmer in the bezel...just not sure if I am going to put the line lock were the n2o switch is and move that or pick up a shift ball with a switch for the line lock. I am waiting to clean up the wiring until I get the switches placed so I have extra length all over the place now...messy.

The fuse panel I have fits right in the passenger side of the console and fits in there like it was meant to go there.

 

[nmcgrawj]

Is the fuse panel just a universal piece from summit/jegs?

 

[blksn955.o]

doing a quick google search this is what I am using. This is not mine but the same fuse box style I am using. I got it at advance/autozone.

 

[COBRA90GT]

FWIW - You can also utilize one of those Littlefuse "add-a-circuit" fuse holder kits for a few bucks at the local auto parts store to tap into an existing circuit (don't overload that particular circuit though).