This is nothing new. 996 models only had one foglight working from the factory, but the bulb holder, bulb and wiring are all present for the opposite side. The non-working side just needs a feed from the installed feed when the foglight is on. Left hand light on right hand drive cars and right hand side on left hand drive cars. Do a web search and there are already guides online; I thought I would add to them.
I have seen examples of wiring running through metal panels with no grommets, wiring connected into the bulb looms rather than the car side of the looms (meaning you cannot remove the light unit when disconnecting the wiring loom at the multi plug), odd routing of the wiring and also any old colour of wire used.
I wanted to run the required wire neatly, protected with an additional sleeve in keeping with factory wiring already in situ, choose the correct wiring colour for the car loom and connect the wire into the car loom as neatly as possible so it doesn’t look out of place. Connecting into the car side of the loom also means when you unplug the multi plug the light unit can still be lifted clear.
You will need:
3m Thin Wall 1mm2 16.5 Amp Single Core Cable. I used Grey with a White trace so it was identical to the factory wiring colour.
3m 3mm Plastic Wiring Sleeve.
A few small cable ties.
Various Tools; T25 Torx, 7mm & 13mm sockets, ratchet, soldering iron, solder, wire cutters, wire stripers, sharp knife.
So basically just under £6 of bits.
The wire and sleeve will need to be cut down.
Time to do the job: Approx 1.5 hours.
First remove the tail lights – Undo T25 torx screws x 2 (engine side), carefully pull the light unit out and towards the centre of the car and then unclip the wiring multi plug (there is a clip underneath the plug). Set aside.
Then remove the airbox assembly. Remove the rubber inlet pipe from the airflow meter to throttle body – loosen 3 x hose clips and lift off. Unclip the air flow meter wiring loom from the 2 clips on the airbox, and unclip the plug from the air flow meter (there is a clip underneath, press firmly and remove the plug and set the loom out of the way.) Undo the 13mm securing bolt from the airbox and carefully lift it clear – take care not to loose the 2 rubber mounts from underneath the airbox that locate into the chassis!!
Starting on the left hand side, remove the light wiring loom rubber grommet (blue arrow) from the panel (gently pull forward) and run the wire through the hole (red arrow).
Now feed it behind the header tank (red arrow)……
and down behind the secondary air pump (red arrow)…….
Once in the engine bay and accessible run the wiring sleeve over the wire (red arrow) …….
until the sleeve appears back through the hole (image below).
Now route the sleeved wire with the loom round in front of the air pump, under the factory wiring looms (red arrows), under the lock/latch mechanism along the back…. Secure the additional wire with a cable tie (blue arrow).
Run the wire round the wiring on the right hand side of the engine bay (red arrows – secure with cable ties) and into the hole behind the right hand light cluster.
Run the single wire through the rubber wiring grommet (red arrow) each side – carefully push a small screwdriver between the grommet and plastic sleeve will make it easier to get the wire through. The end of the sleeving can be hidden inside the grommet (red arrow) then cut the single wire to length where the main wiring loom comes out of the sleeving. (Measure twice cut once.)
Strip about 5-7mm of wire at each end of the newly added cable (red arrow) and tin using the soldering iron and solder. Identify the Grey/White wire in the factory wiring loom where it exits the wiring sleeve (it goes into the multi plug bottom row middle pin) and using a sharp knife carefully strip away a small piece (about 5mm) of the wiring insulation (blue arrow) – do not cut this wire. Tin the exposed wire, then solder the new wire to the existing Grey/White wire in the factory loom. Do this both sides.
Then wrap each new exposed connection with a small piece of insulation tape and tape the new single wire to the existing light wiring loom to keep it secure.
Finish off by securing the new wire to the existing looms (left/right hand side of the engine bay) using a few small cable ties. (See previous pictures).
Push the grommets back into the panels each side, plug the light units back in and refit (align and fix with screws). Test that both fog lights work!! If everything has been done correctly then they will both illuminate as shown in the below image.
Finally refit the airbox and inlet pipe and plug the air flow meter back in and refit the AFM loom back into the two clips on the airbox.