There's very little on the web about changing a fog lamp, and the handbook just tells you to consult your dealer. My fog lamp was damaged after hitting a stone at speed, I know this has happened to other fellow members of the forum, and will likely affect others in time to come. I changed mine today, here's how:
[b]Purchase links & Info:[/b][/size]
I purchased a fog lamp housing from [url="http://www.amazon.co.uk/dp/B004PZ1GCM/ref=asc_df_B004PZ1GCM4498557/?smid=ASP5LPIHKZKSN&tag=shoppingcommp-21&linkCode=asn&creative=22218&creativeASIN=B004PZ1GCM"]Amazon.co.uk[/url] you can get these parts through Ford, however I've heard quotes of £70-£110+ to have it replaced. This one is £23 and although it's not the official Ford part, it is matching OEM quality. (please note the link is drivers side only)
I then purchased a 55w H11 bulb from [url="http://www.autobulbsdirect.co.uk/h11-55w-headlight-bulbs/?bulb_search=c6779&end=front"]Autobulbsdirect.co.uk[/url] I went for the cheapest to match my other fog lamp.
All in after postage & packaging it came to £40, and two days later they turned up:
[b]Tools you'll need:[/b][/size]
You will need:
A flat head screwdriver
A T25 Torx, preferably with a 1/4" socket ratchet
A Torch (helpful, not necessary)
[b]Step #1: Removing headlamp to access fog lamp[/b][/size]
Firstly remove the main headlamp unit, there's a comprehensive guide [url="http://www.fordownersclub.com/forums/topic/12391-the-mk7-fiesta-bulb-change-guide/"]here[/url] for those who aren't familiar.
[b]Close up of the fog:[/b][/size]
[b]Step #2: Removing fog lamp housing from mount[/b][/size]
The fog lamp housing is held to a mount with 2 Torx screws, and 2 locating pins.
The screws are on the top left and bottom right as you look down on it. It's a bit of a fiddle getting them loose.
The bulb just twists and pulls out of the housing.
Once the screws and bulb are out the housing will just pull out.
If you need to change the bulb there is a small clip on the side to take the bulb from it's holder.
[size="4"][b]Fog lamp mount: (fog housing removed)[/b][/size]
[b]Step #3: Replacing everything[/b][/size]
Replace the new fog housing, fitting the bulb first.
Use the locating pins to line up the two torx screws, and tighten.
Quick test, then replace your headlamp and job done.
If you have any questions, just ask, I know the guide doesn't go into great detail but hopefully this guide will help someone, sometime.