Land rover brake lights not working. Fault finding help pls

[2011dandd]

Hi
Got an issue with the brake lights and wanted some advice to have a go at fixing myself.

I’ve got a series 2a and someone put a Isuzu Diesel engine in. Electrics arnt great to say the least. My main concern is that the brake lights are out. I have replaced the units and bulbs and brake switch as it also has a later defender brake servo fitted.
Still no joy on the brake lights so I’m guessing it’s a wiring fault. I have checked all grounds.

Are any of the wires prone to failing in particular places that I could check?

Really can’t a

[healeyneil]

First thing I would do is check if power is getting to one side of the switch

[3.8 MOD]

I seem to remember that the Defenders had wiring inside the rear chassis members going towards the rear crossmember. Maybe the same with a series?

[ARHarh]

Difficult to tell with a 50 year modified car. anything could be going on. The chances of it still having the original wiring is very remote. If you don't understand how to test for electric at various points you are probably not going to fix by guessing.

You need to start by testing for electricity in the bulb holder then work back to the switch then the fuse, The original wiring will have a few lucas connectors in the wiring, these are where the connection will be failing (probably).

[FlipFlopGriff]

Join the 2 wires on the switch (should be on the back of the brake pedal and generally white plastic) and see if they come on. If so its a switch- they are around £5.
Other than that just need to check earths, lives etc as they are most likely connected - one has a feed which loops to the other at the back end. Should be easy to find these wires but they will be hidden under an aluminium cover. Suggest take the o/s off first as thats where the feed will come in from under the tub. If you look under the arch on the o/s rear wheel you should see where a bunch of cables exits the chassis.
FFG

[9xxNick]

If you get one of the books on "how to" for electrical systems in cars, it will be a worthwhile guided learning experience as well as an inexpensive repair.

This one is quite decent: https://www.worldofbooks.com/en-gb/books/a-tranter/automotive-electrical-and-electronic-systems-haynes-techbooks/GOR001643414?keyword=&gclid=EAIaIQobChMI4q6Pg4HF4QIVq73tCh2I2AYbEAQYBCABEgLHTvD_BwE

[838HNK]

Most of my Land Rover electrical issues have been the glass fuses and or the fuse holder getting gogged up ... I ended up replacing the fuse holder with a new one and getting a new set of fuses ... I'd get a cheap multimeter and just go follow the wires !

Edited by 838HNK on Wednesday 10th April 16:38

[2011dandd]

Thanks for all the replies and advice.
As with everything since the bin lids came along. I’m always short on money and time. I will investigate further.

Thanks