Technical Dash warning light for lights when breaking

[Jaka Cvajnar]

Im having a small problem with my dashboard warning lights in my mk2b 5door.

Every time i press the brakes a yellow warning light for lights comes on.
I had this one time before (christmas efect) when i had a corroded ground pin on one of my rear lights,cleaned that and fixed it.

This time i checked all my rear lights, no corrosion(still cleaned it even more), all the lights work as they shauld, even brake lights work normaly when i press the brake. The warning light is always there when i brake, the lights always work properly, tested for 15minutes and every time everything worked fine. What shauld be causing this problem?

 

[Ziggy122]

Correct bulbs fitted?
Not put 5w sidelights in the rear when it needs 10w....

Not put led lights in?

Is it only when braking?
Which means its the brake light circuit

Give all the connections a clean
I often stick a little wd40 in the multiplug and shake excess out before fitting and refitting the plug a few times

This helps restore a poor connection and prevent water foulin so fast

Ziggy

 

[Jaka Cvajnar]

Correct bulbs fitted?
Not put 5w sidelights in the rear when it needs 10w....

Not put led lights in?

Is it only when braking?
Which means its the brake light circuit

Give all the connections a clean
I often stick a little wd40 in the multiplug and shake excess out before fitting and refitting the plug a few times

This helps restore a poor connection and prevent water foulin so fast

Ziggy

No bulbs were changed before the warning started, not halogen nor led.
Only when breaking.
Cleaned the multiplug with wd40 2 times, doesnt change.

Brake lights always work, even when error shows. atleast the 15minutes i tested at home, i dont know if anything changes when i drive.

 

[BILL33]

Dont you get a message saying which light has the problem?

 

[Ziggy122]

Dont you get a message saying which light has the problem?

No
Just a bulb malfuncton indicator thats it

It warns of a fault on the lighting system just not where

Puntos a basic car in technology terms


Ziggy

 

[Jaka Cvajnar]

Update.

I noticed that my left side rear brake light stoped working now(dashboard error like before)

I changed bulbs, still doesnt work.Went to buy another brand new, still didnt work.
I have 2 sets of rear lights at home so i tested the other left light cluster with 3 differant bulbs, brakes DIDNT work there eather, so i rulled out a faulty complete light.

After fidling around i noticed that my rear fog light ( same light) doesnt work eather...


I went to check pins with multimeter and noticed that when brakes are pressed i get around 8v on brake light an around 5v on foglight (even thou fog light is turned off), like the foglight takes voltage from brakelight

Noticed that my foglight uses 5v nonstop even if brake isnt pressed.

So something is wrong with the foglight wiring? any ideas?

I could probly resolve this problem by just cutting the foglight wire, but would leave me without it.

 

[Jaka Cvajnar]

cutting the fog light off did not help, as the wires still draw 5v of power from brakes. this is really confusing.

i removed the rear foglight fuse/relay, and it still supplies 5v to the back of the car?? help

 

[Jaka Cvajnar]

I fixed my left rear brake by cutting the wire before the connector for brake light and tapping the wire on the right side brake wire and feeding it to the left side wire in the connector. The brake lights now work on bouth sides from one wire and no dash warning light. But im still left with a faulty left side brake and foglight wiring, currently just cutted and sealed so they dont make contact with anything. I can live with this as i barly use my foglamp and brakes work just normaly. but would much rather fix the issue than just baypass it. if anyone has any ideas let me know.

 

[varesecrazy]

Hi.
Doesnt sound like an EARTH issue..

But did you check it?

 

[Jaka Cvajnar]

Hi.
Doesnt sound like an EARTH issue..

But did you check it?

i cleaned the plug terminals before i realized it wasnt the problem there. i had all my earths redone my a mechanic a few weeks ago because i was having some other problems.. i dont suspect earth problem as position lights and blinkers run fine. ( and they have same earth as all the lights)

the problem is that my foglamp wire is getting 5v from somewhere even if not turned on ( if turned on its still only 5v) and my brake wire only gets 8v when i press the brakes(thats why the light doesnt work and i get a dashboard warning)

 

[g8rpi]

i cleaned the plug terminals before i realized it wasnt the problem there. i had all my earths redone my a mechanic a few weeks ago because i was having some other problems.. i dont suspect earth problem as position lights and blinkers run fine. ( and they have same earth as all the lights)

the problem is that my foglamp wire is getting 5v from somewhere even if not turned on ( if turned on its still only 5v) and my brake wire only gets 8v when i press the brakes(thats why the light doesnt work and i get a dashboard warning)

How's the weather? Sounds like you might have water in the fusebox or relays.

Other possibilities arre mice chewing the wiring or chafed insulation. Need mehodical continuity (ohms) and voltage checks at all connector and juctions in the wiring for the lights.

Robert G8RPI.

 

[Jaka Cvajnar]

How's the weather? Sounds like you might have water in the fusebox or relays.

Other possibilities arre mice chewing the wiring or chafed insulation. Need mehodical continuity (ohms) and voltage checks at all connector and juctions in the wiring for the lights.

Robert G8RPI.

wheather was nice the past month, no rain. i doubt its water as i checked fusebox and all was fine.

the other option is posible, but im not that good to check all that

 

[Ziggy122]

wheather was nice the past month, no rain. i doubt its water as i checked fusebox and all was fine.

the other option is posible, but im not that good to check all that

Its a common earth lighr setup

So as a result - you may find ghost voltage from earth to another light
As a multi meter measure electrical pressure (voltage) and not unless settings swapped to electrical force (amperage)
If you stuck a consumer on that circuit like a light - the ghost voltage would disappear


As for why suddenly youve lost a brake light - sounds like a short to earth somewhere
So either as suggested water is in a fusebox (not known like GP) or a failing body unit
Or a wire rubbing through somewhere

You dont happen to have towbar wiring do you?
Id be chasing wires back to next connector (probably fuse box) and checking there
You would need a wiring diagrsm

Ziggy

 

[luqluq]

Same thing happened to me last year on the left light. Got suggestion that it may due to earth connection at the rear. So I removed, clean and returned back the rear earth connection. No change.
After more checks, found out that the rear light plate that connect the -ve supply was corroded. So, gave it a thorough rub and smeared some grease ... and it did the job. The bulb light on the dash never shows anymore.

 

[Jaka Cvajnar]

Same thing happened to me last year on the left light. Got suggestion that it may due to earth connection at the rear. So I removed, clean and returned back the rear earth connection. No change.
After more checks, found out that the rear light plate that connect the -ve supply was corroded. So, gave it a thorough rub and smeared some grease ... and it did the job. The bulb light on the dash never shows anymore.

thanks for the info,

i assume that by reart earth connection you mean the main connection. i heavent touched that yet as i assume that if that was the problem bouth rear light wouldnt work. i cleaned only the light plate connection and that didnt fix the problem for me.

 

[BuiltByRobots]

Correct bulbs fitted?
Not put 5w sidelights in the rear when it needs 10w....

soooo wish I'd read that 2 days ago. actually, there were several faults to sort on our 2006 Punto, but this finally cleared THAT issue just airbag lights to sort now.