Bentley Arnage Project - Boot (trunk) Lights

I decided to give Betty the Bentley a good clean the other day, part of that process involved opening the boot lid so I cold clean round the normally unseen bits. It was at that point I noticed there are two lights in there that I hadn't really noticed before. Both were unlit so I thought I should have a look at why that might be - I just like things to work even if I am highly unlikely to need them. I guess if I got a puncture it would be useful to have a light so I can see the tools and spare if it is dark outside. Anyway it was a damn fine excuse to go back in to fix mode and have a prod about.

First job was to remove the little light units and test them, each one has a single capless bulb in a holder that can be removed with a twist. Both tested ok, they are not massively bright but between them should give a useful amount of illumination. If only they worked.

I checked the voltages - there are just two wires - an orange and black one that is a switched earth and a purple one that is a permanent live. For some weird reason there are two fuses marked internal lighting, both seem to do the same job. One is in the passenger footwell fuse box, the other is in the nearside of the boot hidden by carpet. Both fuses tested fine, which was a shame, a blown fuse would have been so easy to fix.

Next thing was to try to understand where the switch is, I assumed it would be near the latch, like the switches in the doors that cause the cabin lights to come on. No such luck, the wire disappears off in to the loom and I can see no switches or anything else anywhere near the hinges, which is where I would expect one to be if there is no switch on the latch. I am convinced either there is a broken wire, a faulty switch or a bad earth feed, if only I could find the shifty little bastard.

I asked on the various forums but nobody could point me in to the right direction, it seems like maybe I am the first to experience such an issue. It's rather challenging. I found the orange / black wire running down the loom and shorting that to earth caused one light to come on but it didn't really get me much further. There is definitely no wire of that colour going anywhere near the boot latch. All this tells me the best way to deal with this is to cheat. My proposed cheat is to leave the live purple wires in place and to put in a tilt switch to switch the negative when the boot lid is lifted. It's not the ideal way but it will work, it's easy to do and it will take a lot less time than searching out this invisible switch concealed God knows where. I shall get one on order as I don't seem to have one. I have had a look at what's available, it seems that the average mercury tilt switch is only about 250mA max current - not enough as the two lights draw about an amp. What I have found is an anti tilt switch for a patio heater, they handle something like 16 amps so should be totally reliable, they are under a tenner. They are quite big but there is loads of space inside the boot lid to hide it, they have two fixing holes so a simple bracket is all that is needed, it will be invisible when finished. It will have to be mounted upside down so it is normally off and only goes to the on position when the lid is lifted. I'll work it out.

Well it took nearly 2 weeks for the switch to get here, turns out it was located in Leicester, China, rather than the Leicester just down the road that the advert on ebay suggested. It was a bit bigger than I expected but it was the straightforward job I hoped it would be. The mounting bracket for the boot lock release looked like the best place to fit it, loads of room and nothing in the way. I found a small bit of steel to make a simple mounting bracket, drilled 3 holes in it and mounted the thing at such an angle so it comes on just before the boot is fully open and goes back off when it's half closed. I earthed one side of the switch and tapped the other in to the brown / black switched earth of the boot lid lights, the two are in parallel so only one connection was needed. A few tie wraps kept everything neat, with the covers back on nobody would ever know. Should last the life of the car too as it's well under it's current rating.