This autolights.co.uk guide applies to any D1S ballast replacement, if you do not want to pay over the odds for a original D1S ballast then this is the article for you.
For illustration purposes, we are using the Porsche Cayenne as an example, the images take of the  Porsche Cayenne were actual footage shots taken each step of the way during the D1S ballast crossover.
This is an 8 step process.
D1S Cayenne ballast replacement

Porsche Cayenne ballast replacement.

Step 1.
The D1S ballast set up is straight forward.
The D1S ballast has two main connection ports:
The first port is where your positive and negative power cables are attached. This allows the D1S ballast to draw power, so as per this example the Cayenne’s headlights will work again!

The second port and corresponding cable connects to the base of the D1S xenon bulb.

Porsche Cayenne Headlamp Front D1Sballast replacement

Porsche Cayenne Headlamp Front D1Sballast replacement

Step 2.

Well the headlamp is a crucial part!
This headlamp from the Porsche Cayenne was really easy to remove, as with all Porsche’s to date, its a really simple process.

Not Much to see at this stage, but note that the factory fitted D1S ballast is located on the underside of the headlamp.

Porsche Cayenne Headlamp Reverse D1Sballast replacement

Porsche Cayenne Headlamp Reverse D1Sballast replacement

Step 3.

On the reverse side of the Cayenne headlamp, remove the dust cover, by pushing both retaining clips outwards from the centre.
Be careful that the rubber part (as seen here above the orange triangle) does not become dislodged.

 

Porsche Cayenne Headlamp Reverse D1Sballast replacement

Porsche Cayenne Headlamp Reverse D1Sballast replacement

Step 4.

Remove the D1S bulb from the housing, and disconnect it from the power cord (attached to the base of the D1S bulb).

Porsche Cayenne Headlamp Reverse D1S ballast replacement

Porsche Cayenne Headlamp Reverse D1S ballast replacement

Step 5.

Once you have removed the D1S bulb, you will be left with the Connector (power cord) which is in turn connected to the factory fitted D1S ballast.

It is crucial that you either disengage it, or insulate it with a good quality  insulating tape.                                                    We insulated the power cord on the Cayenne and tucked the cord away where it was not causing an obstruction.

Porsche Cayenne Headlamp Reverse D1S ballast replacement

Porsche Cayenne Headlamp Reverse D1S ballast replacement

Step 6.

At this stage, you can remove the factory fitted D1S ballast by removing the torque screws. But we do not see the point.

If you intend to purchse an orignal Porsche Cayenne ballast, then sure, by all means remove the faulty D1S ballast and replace it with a new one.

If you are not going to replace the factory fitted D1S ballast with a like for like, then you must consider that you will be left with a gap on the bottom of the headlamp, this is not good! 

Porsche Cayenne Headlamp Reverse D1S ballast replacement power cables

Porsche Cayenne Headlamp Reverse D1S ballast replacement power cables

Step 7.

Locate the power lines that run within the headlamp. Then using the un-attached end from the wires that connect to port 1 of the D1S ballast, connect the red wire to a live source and and the black wire to an earth (negative)source.

It is probably best to find the main Live and Earth wires that run into the actual lamp itself.

This will allow the D1S ballast that you are connecting to draw power and function correctly.

It is imperative that once you have sourced the correct power lines, and made connections, that ideally the wires are soldered, and just as importantly, they are insulated. 

Step 8.

Tidy it all up!

Reconnect the D1s Bulb

Connect the wire from the second port to the base of the D1S bulb

Place the D1S ballast inside of the dust cover, and close the dust cover.

Your done.

Whether you drive a Porsche with a D1S bulb and ballast set up, or whether you drive a Skoda with the same set up, the above is applicable to all D1S set ups.

The same principle is applied to the D2S ballast replacment sequence.