Electrical Modifications

  1. 'gnd' Wire Modification (Relay nr. 5 (Horn))
  2. MSD ECU Relay:
    1. Fan Control
    2. Fan Relay 12v Input Feed Reroute
  3. Windscreen Washer Pump
  4. Accessory Power Outlets
  5. Footwell Lights
  6. Heater Fan Third Speed
  7. Handbrake Warning light
  8. Sidelight Bulb Upgrade

i. Gnd' Wire Modification (Relay nr. 5 (Horn)): My first modification was to relay nr. 5 (the two joined purple wires being replaced by a black (gnd).) This to provide the required gnd [return], as the horn relay needs to be a switched-live as opposed to a switched-earth.

The original configured, purple, was looped from terminal 30 (12v live) back into terminal 86 (gnd) so there needed to be a gnd return in this relay. The gnd feed was fed from relay nr. 6 and I looped this back into relay nr. 5 and then into nr. 7. Bit of tape to neaten it all up and job done...

   IMG 6023 snip

ii. MSD Fan Relay:

1. ECU Fan Control: I modified the GD fan relay wiring (relay nr. 4) by replacing the black/green (85) with the MSD ECU fan control gnd wire (the pink wire.) The ECU takes care of the fan operation as it also has the feed from the water temperature sender.

There is also a facility to control a second fan or a booster capability from within the ECU, so everything is in place for future tinkering... I'm toying with the idea of having two [functioning] fans in front of the radiator to provide a more authentic look (my to-do list is amended).

2. Fan Relay 12v Input Feed Reroute: I routed the fan's 12v live through its own fuse and 12v feed. i.e. took the fan relay power feed off fuse #1 (Purple) and put it on its own live feed directly to terminal 30 on the fan relay... Wasn't comfortable with the fan, horn and the hazards warning live feeds going through the same fuse. 

iii. Windscreen Washer PumpThe washer pump was originally configured as a 'switched earth'. With the Vectra steering column, this becomes a 'switched live' so the green wire needed to be replaced with a gnd. Took the earth (gnd) from an unused gnd from the dash loom (L7).

iv. Accessory Power Outlets: I needed a couple of accessory power outlets. One for my phone and Satnav (a 2x USB unit), and one for my tyre pump (12v cigarette type). So one USB unit on the driver's side and one 12v cigarette type on the passengers' side was the order of the day.

The ideal places for these are bolted to the underside of the dash' trays, just by each side of the tunnel, tucked up behind the air vents. This keeps them within easy reach but out of the way of anything... Didn't want these on the dash' front as they would spoil the look.

Power feeds are from a couple of unused dash' loom spurs (L18, and L20) via their own individual fuses.

v. Footwell Lights: I've mounted the LED footwell lights [CBS LED type] on the bottom of the dashboard under-trays. Not got these wired up yet though. Am undecided on how to have these activated.

Options are, to drill holes in the doorframe and put pressure button switches in, or have a couple of hidden micro-switches which would activate and deactivate the lights by the movement of the hinge when the door was opened or closed.

vi. Heater Fan Third Speed: The GD looms facilitates two fan speeds. These being via plugs L22 and C on the dash’ loom, and plugs 14 (M) and C on the main loom… So I needed to get power and control to the ‘max’ terminal on the fan unit.

Specifically: Ran a wire from the Orange (Max) terminal on the fan unit to the third position on a three-position switch… I used the same cable rating and [orange] colour scheme to continue the existing specification from the heater plug to the switch. Essentially, the new wire does what it is supposed to do with respect to the 3-position switch and the 3-speed fan. The other loom cabling taking care of the existing i.e. power, gnd and fan speeds 1 & 2.

vii. Handbrake Warning Light: This is enabled via a microswitch mounted on the handbrake mechanism.

And the microswitch and spring steel actuator

(which is an old steel ruler cut and bent to shape)

viii. Sidelight Bulb Upgrade (Post IVA): Replaced the supplied 'Capless' sidelight bulbs for LED’s. Did this because the standard bulb takes 5w and an LED takes 0.37w, and it gives a whiter and brighter light.

(Yes this comparison is the sidelights)