HOW TO DIY YOUR FOG LIGHT WIRING LOOM
Comments and suggestions are welcome, detailed pics will be inserted over next couple of days, but let me know if there's anything I need to show in more detail - bear in mind I am a complete amateur at this! Note also that I am wiring mine as 'standard' - the foglights will only operate if your lights are switched on, so you can't swan around with just your foglights on using this build. If you want that, you need to take a positive feed from a permanently live wire rather than the sidelight wire highlighted below. The following assumes you have sourced and fitted the foglights and brackets to the bumper, but let me know if you need any advice for that (dead easy).
Rover 75 fog light loom - paid £20 off ebay for mine, free from scrappy (check connectors match that shown in pics below, other Rover/Landrover looms may be suitable)
Front Fog light Switch
Relay (I used the older chunky yellow relay YWB10012 as it fits into the mounting bracket)
Relay Mounting Bracket/bolt for mounting
17amp wire (Halfords) I used just red and black but coloured would be useful for tracing
Male/female spade connectors (large enough to fit relay posts, approx 6-7mm wide, and switch posts, approx 3-4mm)
Earth ring connectors
Scotch clips (temporary measure only - replace these with 'proper' connectiors, e.g. soldering or piggyback spade connectors at earliest opportunity)
In-line fuse holder and fuse (25amp)
Basic tools (wire stripper would be handy though)
PLEASE TAKE ALL THE USUAL PRECAUTIONS WHEN WORKING WITH AUTOMOTIVE ELECTRICS - DISCONNECT YOUR BATTERY NEGATIVE (BLACK) WIRE BEFORE COMMENCING. AS WITH ALL HOW TO'S, FOLLOW THESE INSTRUCTIONS AT YOUR OWN RISK.
First of all, identify the hole blanking grommet, and remove. Pierce a small hole in the centre of this grommet and REMEMBER to thread wires through the grommet as you pass them through the hole. This helps hold the wires in place and preserves the seal. Poke a long cane or rod through this hole and wiggle until you can see the rod in the passenger foot well, behind the glove box (it'll be behind the carpeting if you can't see it). Use the rod and some tape to help you maneuver wires through the bulkhead hole. With all wires, ensure you leave some slack to play with BEFORE you cut the lengths - better to have wires that are slightly too long than too short! Finally, before we start chopping up wires, identify the area where we will mount the relay bracket so that we know where we are running our wires to - I have chosen to use a pre-existing mounting hole near to the fuse box to attach the bracket, hopefully you have it too. Mount the bracket using a suitable bolt (but leave the relay for now).
1) Remove centre console (link
), and remove blank for fog light switch. (Note that the bank of switches here are 'keyed', but you can remove the 'key' using a sharp blade and rearrange the switches/blanks however you wish.)
2) Examine fog light switch Connectors, on rear of switch labeled 1 to 5.
5 = ground, 4 = Relay post 86, 3 = not used, 1 and 2 = Positive feed from sidelights
3) Switch connector 5 is to be grounded. Run wire from under bonnet area, through the grommet and bulkhead and into passenger foot well, then behind the centre console and through the switch hole in the console. Connect end of black wire to a small male spade connector, wrapped in electrical tape to prevent it contacting neighboring posts, and attach to connector 5 (see pic above). Run the other end of the wire to the grounding point behind the right hand headlight, shown below, and attach an earth ring connector. Don't connect just yet.
4) Switch connector 4 will be connected to post 86 on the relay. Instructions are identical to above except I used red wire, and terminated the wire with a large spade connector close to the mounting hole for connection to the relay later.
5) Switch connector 3 is not used.
6) Switch connectors 2 and 1 will require a positive feed from sidelights (in order to trigger the relay and illuminate switch). Instructions are again identical to above (I used red wire), except you will need to use a scotch clip to branch the wire so that you can connect it to both terminals. Under the bonnet, you must splice the other end of the wire onto the sidelight positive feed. This should be a red/black striped wire in the cluster behind the right hand side headlight unit (you may need to strip off some of the black tape to get a decent exposed length). Piggyback your wire onto this one.
7) You can now install the fog light switch and replace the centre console. Tuck your wiring up behind glove box and dash and secure with cable ties or similar.
8) Next we will connect the fog lights themselves. You can reach up under the bumper and fit the connectors from the loom, no problem at all. It's also easy to route the wires up along the right hand side of the radiator. My loom had two wires, a positive and a ground - the positive had a spade connector, and was routed up near to the mounting hole for attachment to the relay later. The ground wire had an earth ring connector already attached (put one on if yours hasn't) - route this near to the same ground point as previously shown, for connection later. Any slack wiring hanging from below the bumper needs to be secure up out of the way using cable ties.
9) We need to run a wire from the battery to the relay. Run a red wire from the battery positive terminal to the mounting hole - at the relay end of the cable, attach a female spade terminal - at the battery end, fix an earth ring connector and attach the ring to the battery positive clamp, underneath the existing bolt. The in-line fuse connector (with fuse) needs to be spliced into this wire, close to the battery.
10) We're now ready to install the relay. I found it useful to write the terminal numbers on the side of the relay at this point, as you won't be able to see underneath once it's in the bracket. Slot the relay into the bracket.
11) You're now ready to make the final connections. Connect the wire from the battery to relay terminal 30. Connect the wire from the switch to relay terminal 86. Connect the positive wire from the fog lights to relay terminal 87.
12) Relay terminal 85 needs to be grounded, so prepare a black wire with a spade connector at one end to be attached to relay terminal 85, and an earth ring connector at the other end. Remove the bolt from the ground point as shown earlier, and attach the three earth rings you have made - from the relay, switch and lights.
13) Test! Reconnect battery negative terminal, switch on sidelights and press the button. Fog lights should now illuminate.
14) Finish up by tidying all wiring and taping into place. I also used tape to seal and secure individual connections, especially around the relay and any that seemed exposed. If you used scotch clips (tool of the devil) then remember to replace them for more resilient connections in the future - I'll be soldering mine.
That's it, good luck!