Hi,

I'm a new forum member so please forgive me if this is the wrong part of the forum. Hope someone can help - I have searched a bit and not found a similar problem.

Issue : brake lights ( all three ) stay on whenever headlights are on and ignition is on (engine on or off).  If headlights are off, normal operation of brake lights.

Ford Focus Estate 1.8TDCI mk1 year 2002. Towbar and electrics fitted.  No other problems or major work for a long time.

Any ideas where to start looking?

Thanks for any help anyone may be able to suggest.

Edgar

Sounds like a short over from another circuit, I suspect a headlight specific source like the numberplate lights.

The likely cause is a damaged wiring loom in the rubber conduit between the roof and hatch.

First try pulling both bulbs out of the plate lights and see if this stops the problem (would definitely point towards a wiring fault between the live feeds).

Next is to gain access to the wiring loom, pull the conduit back and see if any wiring insulation shows any cracking and if so be prepared to chop out any damage (plus a bit extra to remove any discoloured/oxidised core) crimp or solder in some new wire lengths to recommission the loom.

The reason I suspect the wiring there is because it is a known problem spot due to fragile insulation on aged wires which forms a flex point on the loom and eventually snaps the cores (or at least allows for water ingress which shorts power across between wires causing various problems).

Sent from my SM-G930F