Some people (on a V8) modify the front fog switch wiring to operate the rear fogs. I prefer to tamper with the original wiring as little as possible, so I fit a new switch. (V6 cars do not have a fog switch anyway so you have no choice but to fit a new one in that instance.)

You need an illuminated switch. It should be visible from the driving seat ideally in order to pass a test. I use an after market one and site it near the regular light switch. You can see where I put it from the picture below: 

Such a switch has three terminals.

1) Live in to operate the red LED in the switch, and to feed the switch. (Switch “in” if you like) I take this feed from a front sidelight (some people use a dipped headlamp, but then it tends to go off on main beam). This means the switch will only be powered when the lights are on as it should be. 

2) One terminal is an earth, merely to complete the connection for the  red LED in the switch. Just take one from the under dash metalwork. 

3) The third terminal is the wire that will be fed down to the boot to operate the fog lamp relay that you will fit. (Switch “out” if you prefer.) 

In the boot, you will have a relay you allocated for your fog light. This wire down from the switch will go to terminal 5 on your Omron relays. Refer to the relay page for relay wiring.

The “E” means Europe. Hence American lights are not usually ”E” marked. (The fact that they exceed ours for safety in most regards cuts no ice with Brussels.)

The short version: If a light has an “E” mark on it, it means it has supposedly been approved – somewhere in the EU – as compliant with the myriad of bullshit European regulations applicable to such things.

Chances are, if your light has an E mark, your VOSA tester will not get too involved seeing if it complies to some obscure Brussels rule – he will merely assume it does because it has an E mark. That said, he reserves the right to check something himself if he is not happy with it. My experience suggests they look for an E mark, and when they find it, they say, “Ahh, thats OK then”.

That is not to say that your non E marked American light is not compliant with the rules. It might well be, but he is more likely to check it with light meters and tape measures, etc. if it doesn’t have an E mark.

We are referring here to VOSA testers though. MOT testers seldom have the knowledge or the inclination to get involved in the minor detail of EU regulations and associated Euro babble. I tend to E number the car up for SVA test, and then fit what I want to fit straight after (if it differs).

Below is some Euro babble about light bulbs. If you can struggle through it, you can see why I gave you the potted version above.

An E-mark guarantees an automotive product complies with European vehicle legislation. In the UK, national implementation of Construction and Use Regulation 95/54/EC has made it a criminal offense to use a car with a non-E-marked part fitted. The automotive bulb market is covered by Regulation No. 37, revision 4, defining which bulbs necessitate an E-mark. In general, bulbs that are fitted in external positions on a vehicle must abide by this legislation, although some interior lamps, for example those used in the courtesy lights on the vehicle doors, also require approval.

Furthermore any lamp unit that is E-marked must have E-marked bulbs fitted. The number accompanying the E-mark is not an indication of the quality of the product, a common misconception, but indicates the country in which the testing took place. All countries test the bulbs in the same way against the same standards, ensuring uniformity of the bulbs. Consequently no individual E number can be associated with any superiority in quality.

E1 Germany, E2 France, E3 Italy, E4 The Netherlands, E6 Belgium, E9 Spain, E11 United Kingdom, E13 Luxembourg, E18 Denmark, E21 Portugal, E23 Greece, E24 Ireland, etc. The main checks performed to assess E-mark applicability for bulbs include:

• Dimensional checks ensure a tolerant lamps beam pattern

• Electrical checks certify that the power of the lamp does not exceed the rated value

• The brightness of the bulb, rated in Lumens, is appraised by photometry inspection

• Colour temperature tests check that the colour of the light emitted from the bulb is predominantly white.

It is important to note that life cycle is not part of E-mark testing and therefore differs greatly between manufacturers. It is essential to pick a well-respected brand in order to assert confidence in the longevity of the bulbs.

A legitimate E-marked bulb will have numerous details stamped upon it. These include the E-number followed by a 3 digit approval code unique to the manufacturer and product. The trade mark or brand name should also be issued, along with the rated volts, watts and the letter U if the lamps UV output is tolerable. If the bulb does not possess these stamps, there is a good chance the E-mark is not legitimate.

So what do you do with your old ones? First thing is don’t be a clown and assume that because you paid £130 for your new Euro ones that your old “genuine USA tail lights” are worth £100 of anyones money – they are not!

They are no use to you, and they are of little use to anyone else. I have lost count of the number of US rear lights I have seen on UK eBay with some hopeful soul expecting £120+ for them. They will stay in his garage forever at that price.

The people who will buy them are these folks:

• People who want to occasionally fit US ones for authenticity; perhaps for shows or the American car rally.
• People who are able to convert them to amber indicators and sell them on after they have worked on them.
• People who have a car with converted US lights on who have damaged one of them.
• And… er… thats about it!

The going rate to those folks who can use them is about £50 a pair. Advertise them on one of the Mustang related forums you will find on the page here.

If you do find anyone who is paying a premium for them, tell us all about it using the box below.

The original US spec rear light looks like this:

If you see UK registered cars with these units in, it means whoever did the conversion has used what was the reverse light as an indicator. Not all VOSA test centres will approve this set up now, so unless you can find out that yours will (ie has done recently), dont bother with this set up.

Using the US spec rear lights means you have no provision there for reverse and fog lights, so they must either be fitted in the bumper or below it. There can be further wiring complications with this method covered elsewhere.

Another type you may see are made by a company called “Surrey Mustang”. They convert the US lights to house an indicator in what was a reflector:

These look great and emulate the original US lights better than other options. They are not cheap though, and they will want your old US lights in exchange too. If you can afford them, contact Surrey Mustang through our links page.  This set up still involves tagging a foglight below your bumper.

A popular tail light - one you will see often - is referred to as the “Euro” unit. These are made in Taiwan and look like this:

The inner unit is the fog lamp, the outer is side/tail the centre is the indicator and the reverse is below it. All the lights you need are in this one unit, they are “E Marked” so will pass the test at VOSA. They have a little box on the wiring that takes care of the US tail/brake/turn feeds and you need only add new brake, indicator and fog light feeds.

For the DIY light converter, these are easiest by far to work with. Several places sell them at various prices, but I always get mine from eBay for around £120-£130 including delivery.

For sure, they dont look as cool as the others, but they are cheaper and easier to fit and wire up.

There are a few other LED ones around (that look awful) and converted lights that other companies offer, but these are the main ones. If you know of any others, add the information using the comments box below.