Tapping 12v and Grounds for Aftermarket Items (GPS, Cell, iPod)

[sdg3205]

It's easy enough to tap power for these aftermarket devices, but some locations are better than others and that's where I'm looking for advice.

My PO used to run the fuel pump with splices off the RPM relay, so when I rewired it to stock configuration I was left with what to do with these 2 wires running the length of the car. I decided to leave them in. I'm glad I did because now I have my wiring 75% done.

So:

1. In the relay compartment, where is the best place to tap 12v and a ground. Doesn't matter if it's on key position 1 or 2.

2. Under the dash where is the best place for 12v and ground? Again key position 1 or 2 doesnt matter.

Thanks very much!

[fnzen]

Dave,
Under the dash
Here is what I have found out from my footwell lights installation.

Dennis turned me on to the always hot green wire that is above the pedals.

In addition to that I discovered that the plug harness for the annoying buzzer is also a good source for power and ground.

Don

[sdg3205]

Don thanks so much!

Does "always hot" mean it's live even when the ignition is off? I want to make sure nothing drains the battery.

[fnzen]

thats what it seems to be

[sdg3205]

An obvious place with easy access in the relay compartment is the RPM relay - the live and ground are right there and you get power at the key's second position, but I don't want to compromise that circuit.

I'd definitely prefer something "keyed."

Perhaps the Light Green/White (Feed Main Relay Live When Ignition Is On) to the radio would be best.

When grounding, can I ground it to a frame or bracket or should i connect it to another ground wire?

[Bitsyncmaster]

It depends how much power your going to draw but for most of us it's just a GPS or cell charger.

Tapping off the aux (main) relays is a good place. The main relays are rated for 70 amps and they run nowhere near that.

Fuel pump is a bad idea since it will be very noisy.

[sdg3205]

It depends how much power your going to draw but for most of us it's just a GPS or cell charger.

Tapping off the aux (main) relays is a good place. The main relays are rated for 70 amps and they run nowhere near that.

Fuel pump is a bad idea since it will be very noisy.

Is there a preferred ground, Dave? I've got John's headlight saver rig and it grounds to the mesh on the steering column. I could tap that couldn't I?

[Bitsyncmaster]

Is there a preferred ground, Dave? I've got John's headlight saver rig and it grounds to the mesh on the steering column. I could tap that couldn't I?

If your looking for a ground in the relay compartment, I would spice into one of the black wires up near that bundle of black wires at the back wall. Up under the dash most black wires are grounds. Not sure where the mesh gets grounded so I would not trust that.

[sdg3205]

If your looking for a ground in the relay compartment, I would spice into one of the black wires up near that bundle of black wires at the back wall. Up under the dash most black wires are grounds. Not sure where the mesh gets grounded so I would not trust that.

Actually, John's instruction sheet made the recommendation of using the mesh around the steering when shaft. So far my lights are working great, so it must be decent.

Sounds like using the main relays are the way to go. I can basically use my 2 old fuel pump wires as a 12v power supply for all things awesome. Can't recall the color of the live wire going to the main relays. I'll have to dig up a schematic.

Thanks!

[David T]

Whatever you do you should fuse the power wire. You need to decide if you want it powered all the time, only when the key is on, or only when the motor is running. As for a good ground there is a spot in the console alongside the radio on the right side that is a good grounding point. A good point to tap for power is off the lighter. No one uses it anymore and it has a nice, heavy line. Do not use any "critical" circuit such as brake lights or fuel pump. You do not want to be stuck just because the radio or I pod took out a fuse and now you can't drive home!
David Teitelbaum

[sdg3205]

Whatever you do you should fuse the power wire. You need to decide if you want it powered all the time, only when the key is on, or only when the motor is running. As for a good ground there is a spot in the console alongside the radio on the right side that is a good grounding point. A good point to tap for power is off the lighter. No one uses it anymore and it has a nice, heavy line. Do not use any "critical" circuit such as brake lights or fuel pump. You do not want to be stuck just because the radio or I pod took out a fuse and now you can't drive home!
David Teitelbaum

Couldn't agree more!

The new power outlet i bought came with an inline fuse so I should be in good shape.

[SBL]

Another always on spot on the passenger side is the wire going to the glove box light. That is what I used for my interior under the dash LED courtesy lights.

steve liggett
005983

[sdg3205]

I went with the cigar lighter. I also fixed the illumination light while I was in there!

Since its always live, I put in a fuse and a switch.

Ultimately it would be nice to put in a DMC switch in place of a dummy switch. That way i could charge an iPod without needing my keys. Believe it or not that seems to happen a lot.

[Farrar]

I simply removed the stock cigarette lighter, plugged the hole, taped off the lead for the light, and extended the remaining two leads underneath the console to behind the passenger knee pad, where I installed a double 12v socket underneath. I figured if something goes haywire in one of my accessories and I blow the fuse, I can still drive home without the radio and clock.

Farrar

[sdg3205]

I've got collector plates and can't modify the interior! But good call!