Building an auto VDC off module



From Nissan 350Z & 370Z Wiki

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Annoyed by having to always turn off the VDC? This tutorial will walk you through the installation of a relay that will turn the VDC off at engine startup, while retaining the ability to turn it on or off again using the stock button.

Notes

  • Adding a toggle in line with the relay will allow you to set the prefferred startup mode, i.e. startup with VDC either on OR off depending on how the toggle is set.

Contents

Parts List

  • Time delay relay (Amperite model 12DP.1-60CI,$53.74 at Newark Electronics (www.Newark.com),part #95F1590
  • Radioshack non-insulated butt connectors - size 16-14 (contained in part #64-3036 ; $1.69)
  • four 1-foot long wires (24-gauge works well) - (I used 4-conductor Radioshack Rainbow Wire: Part #2780858; $3.89)
  • miniblade type auto fuse (any amperage) - Radioshack part #270-1093; $1.59

Wire the Relay

You have to attach 4 wires to the relay. Each needs to be about 12 inches long. For clarity I will refer to each wire as a separate color (red, black, white green), but of course any color/type of wire would be fine.

  • Attach one end of each wire to the butt connectors (little hollow cylinders that will slip over the thick pins on the relay itself). I shoved the stripped wire inside one end, soldered it, and then put electrical tape over the entire exposed metal part (connector and all) to insulate.
  • Using the butt connectors, connect two wires to the +/- pins on the relay. Red wire to + (pin 2), black wire to - (pin 7). These are the wires that will be hooked up to the 12V power source to drive the relay. Connect other two wires to pin 3 and pin 1. These two will be hooked up to the VDC switch. You can look at the diagram on the web site if you have questions about the wiring.
  • You are going to hook the other end of the Red wire directly to the fuse box. The fuse box uses miniblade fuses. Take one of the fuses you bought, cut in half to separate the two insertable flat blades, break off the plastic and you should have a little metal piece that you can solder the red wire, with a protruding piece that will be pushed into one of the open slots in the fuse box.
  • Cover all the unused pins with electrical tape to make sure they don’t accidentally connect with something.

Get Access to the Switch

This is the hardest part, because the wires on the VDC switch are short. Also PLEASE be careful not to scratch the soft plastic on the dash during these procedures.

  • Use a small flat-blade screwdriver to pull the VDC switch out of the dash. It will only come out about an inch before you use up all the slack on the wires. Use that same screwdriver to disconnect the switch from the wire connector.
  • Directly beneath the VDC switch is a black hole cover: directly to the right of the hood release. Reach behind and push out the black hole cover.
  • Using your contortionist skills, push the wire connector down behind the dash until it comes out the hole you just made by removing the black piece. The wires should be just long enough for you to see the back of the wire connector. You should see 4 wires grouped together on one side of the connector. The two outermost wires nearest the edge of the connector are the ones you want

Connect the Relay

All work is going to be done from the inside of the car, on the driver’s side. All “front” “right” and other directions are from the orientation of someone sitting in the driver seat facing the front of the car. I will not go into details how where to run the wires, but make sure you think about avoiding areas with moving parts, and making a clean install.

  • Move the driver’s seat all the way back. Take out the driver’s floor mat.
  • Use a large flat blade screwdriver to loosen the two screws on the plastic dead pedal and remove it.
  • Take off the fuse door cover that had been partially blocked by the dead pedal.
  • You are going to remove the plastic trim piece (A) that the fuse door cover was just removed from. Use your fingers to loosen and remove the black plastic nut that was under the dead pedal. To remove the rear end of A, first pry up the second trim piece that is at the door jam to clear the edges of *You can then loosen the rear end of A, and remove A completely, by pulling to the right.
  • Look at the back of the fuse door cover for info about the fuses already installed. There are two rows. On the bottom row (starting from the left) there are three 10amp and then two 15 amp fuses with an open space between the two 15 amp fuses. That open space is the one you want. There are two slots for inserting the fuse in this open space. The top slot should have 12V ONLY when the ignition is in the ON position. Use a multimeter to confirm this in your coupe. Plug the flat blade attached to the end of your red wire into this slot.
  • Attach the black wire to any convenient ground (such as the sheet metal screw/bolt that holds the entire fuse box to the body of the car: directly above the fuse box).
  • Attach the white and green wires to the outermost two wires on the VDC switch connector (either wire on either spot is fine). I did this by bending the ends of the stripped wires and simply jamming them into the correct spots in the connector: they hold quite firmly.
  • The relay has a dial with 10 spots marked. Set it at 1. Start your engine and see what happens. If VDC OFF lights transiently but does not stay on, see if the VDC switch still works to turn VDC OFF. If it does, raise the dial setting slightly. If VDC switch does not work, your setting is so long that the computer has locked out the VDC switch circuit: so lower the dial setting. In either case, turn off the engine and try again. If the VDC OFF light lights transiently and then stays on, you are done. Use a magic marker to mark the setting on your dial before proceeding further.

Mount the Relay

This is personal preference. I shoved the relay up into the dash just to the rear of the fuse box, with the dial facing down. Make sure wires are routed well away from moving parts. When the trim pieces are remounted, the knob is just barely peeking out with the rest of the relay above and forwards. Reinstall all the trim pieces by reversing procedures.

GOOD LUCK AND HAPPY DRIVING!!!

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