Ian Smith

I have a 51 Plate MK1 Focus Estate and for the some reason the brake lights seem to be staying on? This has me completely stumped. I don't have any access to a Diagnosis machine at the moment so any ideas would be a huge help...

martysmartie

iTrader: (1)

Brake light switch is at fault, no need for diagnostics lol, they woulden't show anything up on these anyway!

Check it has not fallen off the pedal first as the way they are wired sometimes they are normally closed so if it's loose etc the lights will be on.

Martin

Ian Smith

i removed the brake light switch, adjusted the pedal just incase it was resting on the switch and replaced the switch as well all seems to be working however now ive noticed that the headlights now come on under braking

martysmartie

iTrader: (1)

That is very strange, that would suggest the brake light power is somehow being 'transferred' into the headlight relay, you have to trace wiring etc.

Martin

Ian Smith

thats what i thought. could be a bad earth somewhere so im going to have to have a good look at it on tuesday since that is the next time im free to really.
cheers martin

martysmartie

iTrader: (1)

Yes check the earth first.

Martin

Ian Smith

Update, i have looked around all of the earths i could find, through some wiring diagrams, and am still stumped. Upon pressing the brake pedal the side lights come on as well as the lights on the dashboard. I have tried to find an earth in the tailgate but I have no idea where it is since its the only one left to check. This honestly has me stumped...

Ian Smith

Final Update, after 3 days of trying to find the cause of the side lights/brake lights coming on at the same time, after ripping the car apart trying to follow wires, reading wiring diagrams, cleaning earth connections i finally worked out what was wrong with the car.

Ready for this...

It was the wrong type of brake light bulb. Yep it was a single pronged bulb instead of a dual prong and was shorting out the two connections. Either way its finally done and sorted now so now i can finally get on with upgrading some components

martysmartie

iTrader: (1)

This does happen, it's just as you never mentioned you replaced the bulb it never occured to me.

At least it's sorted nevertheless.

Martin

Ian Smith

i never did replace the bulb, it was done by someone who previously worked on the car but yes these things do happen it had alot of people including myself scratching their heads over it