Fitting a 12V accessory socket in the rear side trim

[PARR]

Referring to the posts about the 110V power outlet in the rear right panel and the fact that my 1999 RF2 just had a hole, I decided to fit a 12V accessory outlet there.
There is no wiring anywhere near the position for the socket which could take the power needed.
The rear side panel is fixed by two screws in the ‘B’ pillar by the driver’s seat and two screws in the rearmost pillar by the rear door, plus several strong clips along the top.
So – stage 1 was to get an accessory socket – look at Maplin’s site – there are several from which to choose (the socket I bought necessitated some filing to enlarge the hole to an oval to fit the socket).
Stage 2 was to find an earth point behind the side panel. After removing the sill of the rear door (two screws and lever up – the clips popped out), the two screws holding the side panel, pulling the door seal off and then pulling the side panel away far enough to both see inside and to get a hand and forearm in – I saw one within reach.
I used 17A wire (Halfords) – black for the earth and red for the power source, crimped spade terminals for the socket and a ‘fork’ terminal for the earth point.
Stage 3 was to run the power lead behind the panel to the bottom of the driver’s door – I removed the loudspeaker cover in the side panel and the speaker itself, and found a small opening in the structure through which the speaker wires pass. I used this to get the wire forward and upwards to go above the big pockets alongside the centre seats. It is worth getting the wire upwards to ‘stage’ the passage of the wire and leave it sticking out above the side panel temporarily while making sure of the connections to the accessory socket and the earth point and closing the back up again.
Stage 4 was to remove the sill of the driver’s door (clips only – use a chisel wrapped in a bit of cloth to avoid damaging paintwork) and the door seal on the rear of the opening. I then removed the two screws in the pillar – it was easier with the seat fully forward – and (it’s easier from outside) pushed the upper part of the side panel off the bodywork sufficiently to drop the wire behind from where it was left – making sure there is enough wire in the loop inside so that it doesn’t foul the seat belt. I brought the wire out at the bottom of the side trim and cut it with about 6 inches spare.
Stage 5 was to decide where the (illuminated) switch should go in the dash – I put it between the 4-way flasher switch and the steering column, above the little hatch. The switch I used was from Halfords (a red illuminated rocker) and I made the appropriate hole before removing the dash – there is plenty of room behind there and no wiring too close.
Unfortunately in Stage 6 the next lot of wiring needs the dashboard and the instrument cluster to come out – see my post in ‘General Technical/Speedo Conversion’ dated 15 July 2011 – and to decide how to run the power wire from the battery.
Stage 7 Looking under the bonnet, I found a large grommet behind the fuse/relay box on the off-side which had a large wrapped cable going through it (not the small one with a few separate wires going through) and perforated it using a small screwdriver – I didn’t want to use anything sharp – paralleling the bundle of wires. Then I used a drain-cleaning ‘thingy’ (which looks like a long expanding curtain wire) pushing it gently but firmly through the hole I had made for about 2 feet. I then reached up behind the dash and felt around – finding it fairly easily and pulling gently downwards. Looking at the structure I worked out how to get the cable across behind the steering column cluster position to the position of the little hatch in the dash and wove the bendy wire to it. I fixed the power wire to the bendy wire with tape and gently pulled it back from under the bonnet. I left about 1 foot extra from the anticipated route of the wire to the battery and fixed it to part of the wiring harness with a cable tie so it would not pull back inside! I also left about 2 feet extra inside for connecting later (tag this wire to identify it as the ‘live feed’).
I then used the bendy wire again to run another cable from the switch position back across behind the steering wheel and the cluster position then downwards. After detaching the wire from the guide I just pushed it behind the footwell panel so it emerged at the front of the door opening.
Stage 8 There is a plastic former stapled to the carpet and hooked over the seam – I lifted this up and eased the wire under it (it covers part of the wiring harness), bringing it out at the base of the side pillar where the other wire was waiting.
I made an ‘in-line’ connection, wrapped it in insulating tape, and pushed it behind the door trim. The door seal was replaced and then the sill.
I found it better to fix the earth wire for the switch before refixing the dash – a ‘fork’ terminal slipped behind the right-hand bottom screw of the radio mounting ‘box’ is best (not the dash-fixing screw next to the ‘hatch’ - for some reason that did not work!).
I then replaced the dash, leaving the live feed, the supply to the socket and the earth wire hanging out of the switch hole by about 6 inches.
Stage 9 The switch is marked with the connections, so that part is easy. I had added an inline fuse carrier in the live feed with a 15A fuse. (I intended to use the socket to run possibly two portable fridge boxes so they could well take a fair amount of current). There is plenty of room behind the little hatch for the spare wire and for access to the fuse carrier.
I used a ‘fork’ terminal on the power wire from the battery – there is a small terminal integrated with the pillar terminal so that was easy too.
It did work!
(Apologies for the length of the article – but I think I covered all the bases!)

[Vantastic]

Thanks for the detailed description and great tips. I fitted a rear 12v socket in my other car (which has a battery in the rear so a big clue to what car!!) and used 20A wire. BUT I got a cheap in-line fuse and recently running an electric tyre air pump for a longish time (10 mins) the in line fuse melted. So do check the fuse can carry 15A !

[PARR]

As I wrote, I used 17A cable and a miniature blade fuse rated at 15A - I had considered a tubular glass fuse link but as all three of the family vehicles use miniature blades I decided to stay with them.