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Electrical guides and mods

Fitting HIDs

H.I.D. headlights can be found on expensive cars and 4x4s from most manufacturers, now there are kits that allow you to add HID lights to your car.

Modification Details

Important HID Information

Did you know they are illegal to retrofit?
A normal halogen bulb reflector cannot work correctly with an HID bulb.
Although you get more light, most of it is focused nearer to the car.
This causes narrowing of the pupils causing poor night vision meaning you see less.

For the full info, please read this excellent article by Daniel Stern.
Daniel Stern Lighting - Thinking of converting to HID?

What are HIDs?

High Intensity Discharge lights create an arc between 2 electrodes which reacts with a gas
allowing it to release a massive amount pure light at a much lower wattage.

Although HID lights are said to be more efficient because the bulbs only use 35 watts instead
of 45 watts they also use about 8000 volts as opposed to the 12 volts of the standard lamps.

The 8000 volts is fed from a ballast which increases 12 volts
to around 23000 volts and outputs a regulated 8000 volts.

The resulting light is very bright and very clean, the main drawback is unless you get the lights aligned professionally straight after fitting, people think you have your full beams on.

The 2nd drawback is that even the whitest of side lights look yellow next to the HIDs.

The 3rd drawback is that fitting one of these kits to your car is illegal, see above.

Are all HID kits the same?

No way, the real cheap kits are crap and will give you nothing but problems like a lack of radio
reception, earth problems, blowing fuses, intermittent lights and short lifespan bulbs.

One way to see if a kit is cheap is have a look at it. The ballast box should be metal and ideally should NOT have a separate starter. Higher quality kits have the starter built into the ballast.

A lot of kits use brand name ballasts like Hella or Pilot, Hella are a good name to look out for. They don't make kits so the ballasts are usually coupled together with either generic or name brand bulbs. The other problem is there are a lot of fakes out there. Bosch don't make ballasts.

For more information I would recommend looking at HIDs4U 
The kit shown was not purchased from HIDs4u.

Fitting an HID kit

You will need a set of screwdrivers (depending on how your ballasts are fixed),
a hole saw of the correct size (check the instructions in your kit),
Uprated fuses and smart fuse holders.

Firstly, strewn your kit all over the floor and familiarise yourself with all the parts.
Don't touch the glass section of the bulbs. Here we have the HID bulb,
associated wiring, wiring grommet and connectors.

Here is the starter/ballast and all the extra wiring and connectors.

Firstly you will need to remove the front panel,
click here for info, remove the first headlight you want to work on, click here. Unclip the cover on the back of the H7 dipped beam.

Using the correct size hole cutter, drill a hole through the cap.

Put the Hid bulb and wiring through the hole, fix the grommet in place ensuring a waterproof fit.

Now look at the rear of the headlight with the cover removed.

Swing the metal clip down, disconnect and remove the bulb.

Put the new bulb in place and clip down, connect the spade connectors
on the red and black wires to the original bulb electrical connector.

Tuck the wiring down into the headlight out of the way and replace the cover,

Attach the ballast and starter to the car in a suitable location using the supplied fixings.
Make sure they are secure and don't rub or foul anything.
Tiny decided to be clever and attach them to the underside of the headlight units.
Depending on your kit, yours may not fit in this location so experiement.

Connect all of the wires to the ballast and bulb. Bolt the headlight back onto the car.
Depending on the kit you have you will have to do one of two things.

  • Either change your 7.5A headlight fuses for 15A
  • Wire the power and earth wires to the battery or the SAM unit

    Repeat the instructions for the other headlight and test.

    Refit the front panel and go and have the headlights properly aligned at your local MOT garage. They will need to remove the front panel to do this so don't refit it too well.

    Job done, now drive around in the night in absolute awe of the brilliance of these lights.

    Wiring Difference Between Kits

    As mentioned previously, there are two wiring differences in HID kits.

    Some cheap kits take the power from the original bulb connections, pass it through the ballasts and back to the bulbs. The drawback with this system is you have to increase the ampage of the fuse to cope with the extra power required. Depending on the car you can also get problems with:

  • Stalling
  • Blowing fuses
  • Burnt relays
  • Dim lights
  • Total light failure

The other type (like the one fitted here) uses the original wiring to switch extra relays which switch power directly from the battery or a power connector of your own choice.
The drawback with this system is the extra wiring involved running wires to the battery.Better than the other kit design though

Many Thanks
Thanks to Steve (MCCSmart2002) for the miriad of pictures for me to chose from.
Thanks also to Tiny for fitting the HID kit to Steves car.

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