M

Mackers

Well-Known Member
I did create a thread last week but no one's answered my update so you might have been able to see it?

I'm missing something still. My brake lights work on their own. When I put the side lights on and press the brake pedal, the reversing light comes on and the side lights and brake lights go off. I've moved the earth for the one faulty side light and reversing lamp to a different earthing point (which is a good earth). What's going wrong?
 
Usually it’s a bad earth so run a separate good earth to make sure it’s not that,
Then check bulb holders and the bulbs them selves,
Work back from the rear lights along the loom checking any multi block connections,
 
As I said in your other fred:- ( I was agreeing with @mick the builder BTW )

Disco1BFG said:
+1 - it's always a bad earth - either cos the thing has gone completely open circuit - or like in this case where one circuit has lost its designed / designated earth return, and is therefore "forced" to use another circuit for the return...

bl@@dy 'lectrics! they'll never catch on :rolleyes: ;)
Click to expand...

So, It's a bad earth - jury rig a "new" temporary one with cable outside the vehicle to the light fitting in question, and keep testing.... when the problem goes away .... you've found the problem, and you'll have your answer :)
 
There should be an earthing point at the rear offside of the tub. Give it all a good clean - and run a temporary earth from the battery to it to test if it is causing the faults. There should be an earth connection back from all the lights to it.
 
Check the earth connection in the bulb holder and the actual condition of the bulb holders too not just where it earths to the body.
 
mick the builder said:
So are you absolutely sure what needs to be done now?
Click to expand...
I am, it's just that it only started happening when my bulb melted in the side light, I put two new ones on, all the connectors are fine and unchanged and tight, and I sanded and cleaned the earth. I had a few days where everything was OK, but now it's back to square one. But there's new things to try now :0)
 
Just wondering, why would the reverse light come on instead of the brake light when they're wired separately? I've made sure that both the new rear lamp and the reverse light are very well earthed to the chassis.
 
Mackers said:
Just wondering, why would the reverse light come on instead of the brake light when they're wired separately? I've made sure that both the new rear lamp and the reverse light are very well earthed to the chassis.
Click to expand...


Disco1BFG said: ↑
it's always a bad earth - either cos the thing has gone completely open circuit - or like in this case where one circuit has lost its designed / designated earth return, and is therefore "forced" to use another circuit for the return...

I.E. - the brake light earth is missing/bust/fecked/etc.! , so it is earthing through the reversing light
 
Wrong. I put a new lamp unit in. When it was mentioned on here that it was the earth, I took the earth out of the triple bullet connector which earths the side light and reversing lamp and another AND EARTHED THE NEW PRE-wIRED LAMP UNIT TO THE CHASSIS ON IT'S OWN. I still have the same problem, which is: Brake light out, reversing light ON when I press the brake pedal. So, I have also removed the reversing lamp earth from the bullet and earthed it to the chassis earth point. My thought, could the live from the reversing lamp be earthing to the chassis?
 
Mackers said:
Wrong. I put a new lamp unit in. When it was mentioned on here that it was the earth, I took the earth out of the triple bullet connector which earths the side light and reversing lamp and another AND EARTHED THE NEW PRE-wIRED LAMP UNIT TO THE CHASSIS ON IT'S OWN. I still have the same problem, which is: Brake light out, reversing light ON when I press the brake pedal. So, I have also removed the reversing lamp earth from the bullet and earthed it to the chassis earth point.
Click to expand...

NOT wrong at all - now you explain it as above - it seems you have wired the reversing light to the brake light circuit o_O
 
Did these faults only happen after the melted bits problem? Could you have crossed the wires over? Or do the nee units need wired differently?
 
+1 to it being a dodgy earth of some kind. The wiring is pretty simple, just work through it with a circuit tester on each circuit until you find the issue. Clearly something is becoming live when it shouldn’t.
 
Seriously this is turning into one mother F#@king nightmare. Reverse light going out with brake light. I want to die! Any diagrams or sugg
20191116_122326.jpg
estions?
 
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