brake lights not working

[tonytech]

Brake lights have no connection to the horn (other than being on the same page)
Reading the diagram:
Bulbs M9 and M10 earth somewhere in the engine bay, They each seem to share an earth with the reversing lights, so if your reversing lights work the earth should be OK.

[clift_d]

I think all the lights in each of the rear clusters share a single return feed to earth, so if there was a bad earth to either of the clusters then none of the lights in that cluster would work. The fact that both brake lights aren't working suggests that the problem occurs at, or before, the engine bay junction box, which is where the single brake light feed from the front of the van splits into two.

If as you think, you have 12V to the switches then you should, as lloydy says, try bridging the two sides of one of the switches with everything connected. If the brake lights come on when you do this then it's the switches that are kaput. If not then it is a connection issue somewhere further down the line.

Tracking from the brake switches, the feed (red-yellow) and return (red-black) wiring from both switches should go via the same two pin connector behind the dash (T2g on the diagram on pg 12), into the front end loom and from there into the fuseboard through multi-pin connector-C on the back of the fuseboard (see the diagram on pg 1). From the fuseboard the feed then comes back out via multi-pin connector-E (pg 1) into the front end of the main loom.

At the back end of the van the main loom connects via a 7 pin cylindrical(?) connector in the engine bay junction box (T7 on on pg 12) to both feeds for the rear light clusters.

In the morning, track all the connectors as above and check they are all snug. If that doesn't work, stick a couple of house bricks on the brake pedal and use your multimeter, where you can, to track how far the +12V feed is getting, which should then narrow down where the fault is.

Good luck with it.

[chuckle-bus-tom]

Bridged the terminals with a bit of wire and lights came on, so I changed the switch and all is good now. It was possible to do without draining the system, and I only lost about 2 tablespoons of fluid in the brief seconds between switch changes. Caught most of the fluid in an aerosol cap stuffed with tissue. I wanted to drain the system and replace all the fluid, but there was no way in hell the bleed nipples were coming undone!

Thanks for the help guys!

[clift_d]

If you haven't already done it, you probably need to consider replacing the other switch as well - it sounds like they were both knackered.

Well done.

[chuckle-bus-tom]

If you haven't already done it, you probably need to consider replacing the other switch as well - it sounds like they were both knackered.

Well done.

Thanks!

And yes, I was wondering about the other switch. It took me a while to make up my mind which I needed to change because neither Haynes or Bentley acknowledge it, so I didn't know what it does! I assume it's the same type of switch to buy?

[clift_d]

I assume there are two switches for reasons of redundancy, presumably it is the same kind of switch in both.

[Lollypop]

hi guys sorry to jump on the post but I have same problem, ive just bridged spades as lloydy said and bingo,brake lights came on,i have two switches,are they both the same and should I change them both ?,replies ,advice appreciated,thanks Laurence.

[chuckle-bus-tom]

I just changed the one that's half way on the master cylinder and my lights work fine now. I still can't find conclusive answers about the switch at the front, but when I get five minutes I'm going to change it for the same type. For now I've cleaned up its terminals, just because that's the kind of thing that these vans seem to like. Kind of like a cat being tickled under the chin.

[clift_d]

Exchange whichever one is easiest in the first instance and the other when it's convenient - it sounds like they're both knackered. The two switches are both on the same circuit and read the same thing. If the brake lights aren't working and come on when you bridge the contacts of one of them then both are dead.