M

mattsccm

Member
Any bright ideas of where to go next? Brake lights were working when I last looked , maybe a month ago. Not any more. Was checking the trailer board and no brake lights. Checked that a known good vehicle. All good. So back to the 110. Bulbs swapped out to double check. Nope. Fuses the same , nope. Brake light switch shows current is good with circuit tester. Wiring behind the lights and that area is fine. Earths are not visible apart from the battery. Now of course I could strip out every inch of purple/green plus the black earth but is there something sneaky that I have missed. Newish vehicles like this, 2002 are somewhat over endowed with electrickery and are beyond my skill set. (I peaked at 300tdi) . Could the non working high level brake light be the issue although this has never worked? If I go back though the circuits with a tester and try each and every green/purple junction plus the black earth am I going to eventually spot the problem or is something computery going to mess me about.
Would a generic code reader show the problem. Not got one but I know a chap who has and can use it.
Ta all.
 
You have a brake live at the rear lights?
Put a temporary earth from the bulb holder to earth and see if it works.
Is there an earth point behind the rear lamp inner covers?
High level brake light earths through the heated rear screen earth I do believe, it's very common for them to fail and can be fixed with an additional earth wire going up to the bulb holder. Mine has failed and been fixed sometime when the previous owner had it, think it's also a mot fail.
Edit: Pretty sure a code reader will tell you nothing.
 
Last edited:
Hi level brake light has the usual damaged connectors in the heated screen. . Didn't seem to fail the MOT May just bypass that one day with a bit of twin core speaker wire. No earth behind the inner covers. Just realised that my tail lights wouldn't be good if the earth was screwed. I assume.
Irritatingly the bulb holder has a fancy moulded connector that then goes onto the look with tiny flat pins thus needing a fiddly circuit tester. No power at this point. Grr
 
mattsccm said:
Hi level brake light has the usual damaged connectors in the heated screen. . Didn't seem to fail the MOT May just bypass that one day with a bit of twin core speaker wire. No earth behind the inner covers. Just realised that my tail lights wouldn't be good if the earth was screwed. I assume.
Irritatingly the bulb holder has a fancy moulded connector that then goes onto the look with tiny flat pins thus needing a fiddly circuit tester. No power at this point. Grr
Click to expand...
It would seem you have an earth if your lights work are you sure you have a brake live then?
 
Well that seems to be the issue. Tell me. If I bridge across the two wires heading for the switch, by passing it , will the brake light come on if all is well? Would be a handy way of keeping the circuit "live" rather than jamming a jack handle on the brake pedal or keeping the wife in the vehicle.
 
Have bridged across the stop light switch. Still no live feed so I think I have a break or something in the loom.
Have just found on one of the large block connectors a purple wire, thicker than all the rest with what appears to be a bullet end going into the block. No idea what it does and doesn't appear on the Haynes wiring diagram. Never seen one like this before Tis very broken.
Looks like I just have to go through all the connectors in order. Will having them disconnected and thus other elements having no power be an issue?
 
mattsccm said:
Have bridged across the stop light switch. Still no live feed so I think I have a break or something in the loom.
Have just found on one of the large block connectors a purple wire, thicker than all the rest with what appears to be a bullet end going into the block. No idea what it does and doesn't appear on the Haynes wiring diagram. Never seen one like this before Tis very broken.
Looks like I just have to go through all the connectors in order. Will having them disconnected and thus other elements having no power be an issue?
Click to expand...

Have you check the trailer socket for integrity ?
 
www.ebay.co.uk

Car Circuit Tester Voltage Automotive DC 6V-12V-24V Test Light Electrical Pen ~@ | eBay

[Wide Application] Test a range of circuits from 6V to 24V, ideal for checking to detect open circuits, fuses, tuning. Tester size Tester size: 14.5x7.7x7cm. 1 x Car Circuit Tester. [Easy to Use] The handle will light up if the circuit is good.
www.ebay.co.uk
Do you have one of these?
I am not sure how the circuit works so making some presumptions.
Test for live into the brake light switch if ok then test for live going out when pressed. If ok then test at the bullet connection behind the rear lights, I think osr.
If nothing then get a length of wire to go from brake light switch (output) to the bullet connector, if that operates the brake lights then broken wire somewhere.
If still not working hit it with a hammer!
 
Been through it with a mate who does these things. Switch good and tested. Bulbs good, tested and proved. Fuse the same. Earth good as proved by functioning tail lights. Right through the bulb holders all tests perfectly but stick a bulb in and it doesn't work. Even tried bypassing bulb holders and swapping terminal to see if the system would work with 5w tail light. Nope. 13v when engine running at bulb holder but only 11 without.
Going to try new holders and bulbs tomorrow but each bit works perfectly until I mate bulbs to holders. Got to be the holders. High brake light not attached as terminal to windscreen knackered. Could this be the problem?
 
have you checked the header
 

Attachments

  • brake lamps.png
    brake lamps.png
    199.6 KB · Views: 31
This question probably shows up why I'm no good at electrics, why does the ecm get involved?
Would this be for vehicles with ABS?
 
Well, no further on. Haven't checked the header mentioned for a number of reasons. a) no idea where or what it is. b)Doesn't feature on my Haines manual wiring diagram. Vehicle is 02 not 99 as in the diagram above. c) Still have power into the bulb holder so it should work.
Just fitted new bulbs holders and more new bulbs. No further along. Would a non connected high level brake light be a problem? The wiring for this bear no resemblance to the wiring diagram . See c above.
 
I could be wrong but I don't believe the high level brake light is relevant.
It's very strange that you have 12v into the bulb holder and a good earth and it still doesn't work.
 
Still no further on. Thinking of running a decent earth and live feed from the fuse to a test bulb holder and working my way through each junction until I find the problem. It has been suggested that a dodgy junction may allow enough live feed to indicate on the multimeter but not when loaded with 21w. Clutching at straws a bit really.
 
Well, it's done. Went back painstakingly through the loom from each side. Bypassed the junction box where things stopped working and pulled that apart. What looked fine actually had a broken pin. It could in theory make contact and did if you whacked it closed but wiggled loose. Had something more robust in the shed so replaced the junction with that. Job is done and I even got round to wiring in the high level brake light as well! Thanks all
 
mattsccm said:
Well, it's done. Went back painstakingly through the loom from each side. Bypassed the junction box where things stopped working and pulled that apart. What looked fine actually had a broken pin. It could in theory make contact and did if you whacked it closed but wiggled loose. Had something more robust in the shed so replaced the junction with that. Job is done and I even got round to wiring in the high level brake light as well! Thanks all
Click to expand...
Well done. What junction box are you talking about?
Maybe post some pictures to help others in the future.
 
You must log in or register to reply here.

Similar threads

Seph98
Tail lights only flickering
Replies
10
Views
911
Dippypud
Dippypud
J
110 Defender Side lights
Replies
0
Views
289
Jase B
J
J
Brake lights
Replies
4
Views
784
300bhp/ton
300bhp/ton
C
Help please problem bleeding 110 with ABS new brake master cylinder
Replies
3
Views
742
Civeng
C
MrGorsky
P38A Service Brake right on the MOT limit...
Replies
10
Views
887
roythebus
R