Engine running on

[Slo]

Well the cluster is fine inside clean as a whistle and I made sure the brake and tail bulb wasnt touching contacts together.

[Capncol]

Not sure which is causing it but i disconnected the os rear cluster and its stopped doing it im just going to open it up for a look.

How the hell can the brake light circuit hold the igntion and radio on lol

Rear lights can cause some weird faults, specially with can bus.
Have you tried it with all the bulbs out of the o/s cluster?

[Slo]

No never thought to try it while I had it apart, I just assumed it would be fouled up but when I saw it was spotless I just reassembled it.

In all the time i've had this car whenever I brake the front o/s sidelight lights up too, could be related.

[Capncol]

Have a close look at the O/S brakelight bulb. The filament may be touching.

[IanL]

I've just checked the SEDRE, and the brake pedal switch is supplied from the ignition, so, if the ignition is off, there must be a short between that conductor and the non-ignition-fed side. The most likely place would be in the BSI, but it could be in a cable loom.

You might be able to pin it down by selectively pulling fuses until it stopped happening.

[Slo]

Aye but whats making it frustrating is it only does it with the headlights on and pedal pressed so a double feedback/bleedthrough somewhere. I could live with it except for the front offside sidelight lighting up when i brake.

It can only be a faulty earth or something has been bypassed somewhere

[Slo]

Decided to investigate this annoying problem again as i've now got no brake lights. Well actually thats not acurate it lights up both stop and tail on the nearside and tail light on the offside but when ive got the lights on there on permanent so no different when pressing the pedal, ive had the entire dash out, bsi out and stripped, all relays click when probed and all points re-soldered, put it all back together and its exactly the same except now instead of the front offside sidelight lighting up when braking its now changed to the nearside.

So i doubt it will be the bsi as the loom for the rear clusters corners off through the bulkhead to the engine fusebox.

Tomorrow its coming out and getting stripped and inspected.

IanL can you see on sedre where the power feed comes from for the stop and tail lights, im sure its the engine fusebox, according to autodata it is but it just shows it comes from it not where abouts.

[Powellct]

Not sure which is causing it but i disconnected the os rear cluster and its stopped doing it im just going to open it up for a look.

How the hell can the brake light circuit hold the igntion and radio on lol

Rear lights can cause some weird faults, specially with can bus.
Have you tried it with all the bulbs out of the o/s cluster?

Ford used to suffer terrible in the late 80s, albeit it never fed back to the ign circuit. Can you swap the cluster r with a known good one from anyone local? Just a thought.

[IanL]

IanL can you see on sedre where the power feed comes from for the stop and tail lights, im sure its the engine fusebox, according to autodate it is but it just shows it comes from it not where abouts.

No, its from the BSI. Right Brake Light Fuse 20, Left and center Fuse 21. Taillights, surprisingly, are not fuse protected and are fed directly from the BSI processor.

The loom from the BSI is 46HAB, and all the connections to the tail clusters go from socket 16V NR. Now, there's a thought (crud in the plug/socket?)



Of course, all power to the BSI come via the engine compartment fusebox.

[Slo]

Thanks IanL Ive just had a look F20 is 10 amp and F21 is 15 amp, that plug 16V NR is black and looks clean as a whistle, oddly non of the wires going into it match the colours of the wires going to the cluster, they all go into the engine fusebox. Ive got my fusebox off now in front of me and its loaded with relays but am unable to open it as its one of those soldered together types......

Also another oddity to me but may be perfectly normal the earth on the bulbs in the rear clusters is infact live and feeds are earths is that correct?

[IanL]

That is all very different to what I see in the SEDRE. Perhaps I have not found the correct data for your car. Can you post or PM the last eight digits of your VIN.

The SEDRE is not detailed enough to check the polarity of the bulbs. Of course, which terminal the positive is applied to is just convention - it would have no practical effect, unless the bulbs were LEDs. I assume your battery is not connected positive to earth - that would be most unlikely these days.

[Slo]

Well my mate has broughgt his 51 plate 2.0 hdi and its got a first gen engine fusebox. Despite them being different and with ignorance weve swapped them over and his car is working fine and mine is exactly the same so that rules out the fusebox entirely and I can confirm that they are interchangeable too.

No its not a positive body on the car that would be silly, in the rear clusters the earth as you would expect that links all the bulbs together is positive, dunno if this might be the cause or not but only thing left to try is the rear clusters now.

[Slo]

FIXED by re-reading old replies and Col was right on the money (I did try taking the bulbs out at that time of posting and it made no difference ), took all the bulbs out and reinserted them one by one and it turned out that the ns stop n tail bulb was somehow arcing power to its other circuit so with it removed the o/s worked fine, put sidelights on and reinsert the ns bulb and the ns bulb sidelight would work ok but the os brake light would come on too then when pressing brake pedal no difference at all.

Put some new bulbs in and its working perfectly except the boot brake light strip no longer works.

IanL thanks again for that insight into the sedre information that was helpful. Can you find out where the middle brake light joins the left hand brake circuit?

Can't believe ive taken the entire dash out and stripped the bsi and engine fusebox completely out twice over time and all it was was a sodding bulb lol

The engine no longer runs on as before either, however it opens up the possibility to bypass the immobiliser if you need to get one to run if you have immobilizer problems.

[Capncol]

Glad it's sorted.

[IanL]

Can you find out where the middle brake light joins the left hand brake circuit?

It is fed from the BSI on a wire which is separate to that for the LH cluster, but comes from the same Pin No 1 in 16V NR. It then goes via the same harness, 46 HAB, into a passenger compartment harness to boot lid harness interconnector (ICKO 9V NR, Pin No1) , and thence via 79 COF to the lamp fitting.

(Btw, NR = noir = black)