Xenon OEM Headlight Retro-fit Guide

I have recently performed the relatively simple task of upgrading my 2005 Mondeo from ordinary halogen headlights to the Xenon HID headlights.

Wiring Diagrams

The wiring diagrams for the halogen headlights are pretty simple, and show the connections to and from each of the pins on the 7-pin headlight connectors (C146 & C147):

It is worth noting that Fuses 16 and 18 (both 7.5A) have to be upgraded to 20A to support the xenon lights.

The wiring diagram for the Xenon HID headlights is a lot more complicated, but we only need very few details from it. Again, it shows the connections to and from each of the headlight connectors:

As you can see, there are a lot more wires going to the xenon headlights, most of these are for the automatic levelling system, which connects to sensors in the axles of the car to ensure the xenon lights remain aimed properly (to aviod blinding oncoming drivers). To get the xenons to work, this is not needed (the manual headlight adjusted can be made to control the xenons instead).

Headlight Connectors

The halogen headlights have a white male connector built into the rear of the light unit, and the car's loom plugs straight into this with a balck female connector. As you can see, different colours of wiring are used on the car loom and inside the headlight. Both are shown below:

The xenon connector for the Left (N/S) headlight is shown below, with only the wires required to get the xenons working labelled:

Conversion Loom

I cut the wiring from the inside of an old halogen headlight unit (bought from scrap yard for £5 as the lens was broken) as I didn't want to start butchering the car's loom. This left me with the white male connector with a good 6 inches of wiring going to each pin.

I then cut the connector off the xenon headlight (this is an expensive point of no return) and joined the relevent wires to those connected to the halogen male connector, using ordinary 15A connector blocks.

I was then left with a xenon headlight with a halogen connector, ready to plug into the car's existing loom. The advantage of this method is that the xenons can easily be swapped back to your ordinary halogen headlights in a metter of minutes.

Materials Required

• Pair Mondeo (2000>) Xenon Headlights (eBay is best bet for these).
• 2x Mondeo (2000>) Halogen Headlights (broken ones from scrap yard, as all you want is the connector)
• 14x Connector Blocks (15A)
• Lots of black electrical tape
• Wire Cutters
• Wire Strippers
• Flat Screwdriver

Hope this helps, photos to follow!

Submitted by dazedconfused