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Discussion Starter · #1 ·
Hey,

I finally got some free time and I want to hook up my DeFi boost gauge. The problem I have is I can't figure out which wires to hook it up too and was hoping someone could give me some direction. I do have a shop manual and have spent hours going through it trying to find something useful. Meanwhile, the instructions for the unit say I need four wires:

- Battery (Constant) 12V
- Ingition 12V
- Lights 12V
- GND

So far my best bet is to hook into the "Auto Light" plug. It has all three I think but I have two problems/concerns...

1) The wires are really high up and it'll be tough to solder the connections (not impossible though)

2) The lights line is 12V when lights are off, and then drops to 1.5V when the lights are on. This seems backwards to me. Is this what the DeFi wants?

So... long story short. Can someone please put me on the right path here?
 

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Hey,

I finally got some free time and I want to hook up my DeFi boost gauge. The problem I have is I can't figure out which wires to hook it up too and was hoping someone could give me some direction.

I do have a shop manual and have spent hours going through it trying to find something useful. The instructions for the unit say I need four wires:

- Battery (Constant) 12V
- Ingition 12V
- Lights 12V
- GND

So far my best bet is to hook into the "Auto Light" plug. It has all three I think but I have two problems/concerns...

1) The wires are really high up and it'll be tough to solder the connections (not impossible though)

2) The lights line is 12V when lights are off, and then drops to 1.5V when the lights are on. This seems backwards to me. Is this what the DeFi wants?

So... long story short. Can someone please put me on the right path here?
[/b]
Ignition, and lights just get the power from the Cig lighter wire (you might want to add a fuse in line to be on the safe side)

Battery still havent done it myself so I lose all my settings each time I turn the car off but the easiest way would probably be to runn a wire from the battery. (definetly with a fuse)
 

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Discussion Starter · #3 ·
Ignition, and lights just get the power from the Cig lighter wire (you might want to add a fuse in line to be on the safe side)

Battery still havent done it myself so I lose all my settings each time I turn the car off but the easiest way would probably be to runn a wire from the battery. (definetly with a fuse)
[/b]
Is there an easy way to get to the cig. lighter wires on the drivers side or do I have to take the dash apart? (Was really hoping I could avoid that).

Am I correct in thinking that the light wire goes "high" when the lamps are on, which dims the gauges?
 

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Take everything to the fuse box.
 

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Am I correct in thinking that the light wire goes "high" when the lamps are on, which dims the gauges?
[/b]
This is correct. I placed my controller in the center console.
I wired my unit into the seat heater switches. One of the wires on the switch is a constant 12v when the ignition is ON, another is a 12v supply when the lights are turned on. I used a constant 12v lead that I found in the radio harness and grounded to some bolt in that general area. Obviously this is only an option on the GT model, but I thought I'd throw out my install info. I would imagine you could get the same thing out of the lighter/ashtray harnesses like strtfghtr mentioned. You don't have to take the whole dash apart, you can take out the cup holder and then pull up on the part that surrounds the shifter, the ashtray is part of that piece.

I would not recommend connecting +12v and +12v Lights to the same source. The +12v Lights is used to dim the gauge and light up the buttons when you turn the exterior lights on.
 

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Discussion Starter · #6 ·
Oh, I didn't think of using the seat heaters. Thanks a bunch for everyone's help. My hope is that I can tap into the wires as they come out of the fuse box by using the colors and the wire schematics from the shop manual.

I'll attempt to use:

- The +12V Ignition from the Cig Lighter (my assumption that 99% of draw will come from here)
- The +12V Battery from one of the interior lights (I suspect it'll use very little draw to store settings while car is off)
- And the +12V Lights from the heater (little to no draw, since I suspect it just uses this as a digital switch to detect headlights)

That should spread out it's draw w/o bringing down anything serious if the unit goes haywires. I'll post my experience up assuming all goes well... although I've managed to screw at least one step up in every install I've done so far! (Yay for being a noob :p).

Hehe, I should make a what-not-to-do guide... but at least I'm trying to do it all myself.
 

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Just some food for thought. Not sure if these little details matter to you or not.
If you notice the stock gauges light up when the Ignition switch rolls to ON. If you tap into the cig lighter your gauge will turn on, then off while the car cranks, and then back on. Also, if you turn your ignition to ACC the Defi will light but your stock gauges will be off.
When you wire the +12v Ign. to the seat heaters 12v source, it turns on when your ignition is in ON or START so it doesnt cut out while the engine is cranking. I prefer to have it this way so that all the gauges light up at the same time, and to prevent unnecessary on/off of the Defi while cranking.

You are correct about the +12v Lights having a very very low draw, it is more of just a voltage sense wire.
 

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You need a digital multimeter. You can get them for a couple bucks and it will save u a lot of time. Everyone should have one in their tool box.
[/b]
yes, definately. I should have mentioned it, thats how I found my leads.
One of the most handy tools when it comes to mobile electronics.
 

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Discussion Starter · #10 ·
yes, definately. I should have mentioned it, thats how I found my leads.
One of the most handy tools when it comes to mobile electronics.
[/b]
I actually have a multimeter, but I couldn't figure out a good way of testing the wires without jamming a pin through 'em. With that aside, there's literally dozens of wires coming out of the fuse box, I didn't want to start wreaking havoc without at least some direction.

Is there a "trick" to multi-metering them? I mean, it's hard enough just crawling under the steering wheel while on my back, little to no illumination, and both hands on each lead for the multi-meter...
 

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power from the Cig lighter wire (you might want to add a fuse in line to be on the safe side)
[/b]
I did this, but with out the fuse? What amp fuse? 10 amps??? or higher?
 

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Discussion Starter · #13 ·
Alright. So last night I pulled the center console out and managed to solder the IGN, Light, and GND wires to the front cig lighter.

I tried and tried to find a battery line in the bundle of wires next to the shifter to no avail. All I managed to do is make the bundle of wires look like they got attacked by a rat... and I was getting worried I would screw something up so I just gave up :(.

For now I've just wrapped and taped the battery line to the ignition, which works okay but I lose the warning settings everytime I shut it off.

So, anyone know where I can tap into a battery line easily? I'm about 10 seconds away from running a line from the battery itself, but I'm sure there's got to be at least one easily accessible place...
 

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Alright. So last night I pulled the center console out and managed to solder the IGN, Light, and GND wires to the front cig lighter.

I tried and tried to find a battery line in the bundle of wires next to the shifter to no avail. All I managed to do is make the bundle of wires look like they got attacked by a rat... and I was getting worried I would screw something up so I just gave up :(.

For now I've just wrapped and taped the battery line to the ignition, which works okay but I lose the warning settings everytime I shut it off.

So, anyone know where I can tap into a battery line easily? I'm about 10 seconds away from running a line from the battery itself, but I'm sure there's got to be at least one easily accessible place...
[/b]

Just go to the ignition harness, the wire should be black/yellow.
 

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Discussion Starter · #15 ·
Just go to the ignition harness, the wire should be black/yellow.
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Is that the one attached to the bottom of the steering wheel? Can I remove the bottom panel for better access?
 

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Is that the one attached to the bottom of the steering wheel? Can I remove the bottom panel for better access?
[/b]
Yes and Yes.
 

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You can also probe one of the Red wires in the radio harness. There is a constant 12v wire in there that retains radio presets. I have mine wired in there with no issues.
 

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Discussion Starter · #18 ·
You can also probe one of the Red wires in the radio harness. There is a constant 12v wire in there that retains radio presets. I have mine wired in there with no issues.
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I considered that but it looked pretty hard to get too. How did you get access to it? Did you take the radio out?
 

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I considered that but it looked pretty hard to get too. How did you get access to it? Did you take the radio out?
[/b]
Oh yeah, I forgot about that minor detail. :)
Yes, you have to remove the radio.

Where are you planning to put the gauge?
 

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Discussion Starter · #20 ·
Where are you planning to put the gauge?
[/b]
Excellent question! Right now the plan is to also get an EGT and Oil Pressure in the very near future so I'm planning for a three gauge setup. I bought one of the 45mm Lotek pods and I'm hoping I can dremel it to fit in three 60mm's although it's going to be tight.

If that doesn't work out then I'm going to try and mount them on the underside of the flip up hatch where the navi would have been. But I'll only do that if I can still close it properly which would give me that stocker look.

I did consider the using the column like you did, but I really don't want to have to worry about what would happen if that airbag were to deploy. I know it's only supposed to deploy from the top, but if that panel pops off the gauge could end up shooting at my passenger or something.

I've already taped the control unit to the bottom of the dash on the right side of the steering column. That was just too perfect of a fit and place to pass up.
 
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