The high mount brake light on my 2003 Ford Focus doesn’t work. There is no power to the unit. The unit has a black wire (ground) and a green/yellow wire (hot). The hot wire is attached to the brake light switch on the brake pedal.
I checked for continuity on the hot wire by checking at the switch and at the light. No continuity. However, when I ran a separate wire from the brake light switch (green/yellow wire) to the light (green/yellow wire) the light stayed on all the time - effectively bypassing the switch.
It doesn’t seem likely that the hot wire is broken some place because as far as I can see the hot wire is pretty secure. Is there something else in the circuit? Any ideas? How can there be no continuity on the hot wire and yet when I run a duplicate wire there is power but the switch is bypassed?
You connected to the wrong side of the brake light switch. You need the other terminal.
You are assuming that a power wire goes straight to the high mount brake light, like the lower brake lights. This isn’t necessarily correct. I can’t bring up a brake wiring diagram from my usual sources, but, your high mount brake lights may have a module between the brake light switch and the high mount brake light. The repair manual usually has the wiring diagram. You got one? The public library may have one. Ask a librarian.