No Brake or Reverse lights

[oldie]

Just replaced aftermarket reverse light on my MY2010 Puma trayback. And now the reverse and brake lights are not working. Are they related or is it a coincidence.
Checked fuses. After initial install of new lamp only had 7.7 volt on reverse power lead at the back. Now 0 volts. Because it is c/chas trayback from factory, rear wiring is not plug and play, but it all worked fine until my intervention yesterday.
I have wriggled connector on gearbox reverse switch for no joy. Reverse lights work if disconnected from main loom and external power applied.
Tail lights and blinkers work fine so earth is good.
So I had a look at stop light switch. There are 2 on the bracket. Why ? Is there something tricky here ? Don't want to cause any more problems.
Where to look next ?

Oldie

[Tins]

Just replaced aftermarket reverse light on my MY2010 Puma trayback. And now the reverse and brake lights are not working. Are they related or is it a coincidence.
Checked fuses. After initial install of new lamp only had 7.7 volt on reverse power lead at the back. Now 0 volts. Because it is c/chas trayback from factory, rear wiring is not plug and play, but it all worked fine until my intervention yesterday.
I have wriggled connector on gearbox reverse switch for no joy. Reverse lights work if disconnected from main loom and external power applied.
Tail lights and blinkers work fine so earth is good.
So I had a look at stop light switch. There are 2 on the bracket. Why ? Is there something tricky here ? Don't want to cause any more problems.
Where to look next ?

Oldie

Did you use led replacements? If so then polarity is important.

[oldie]

Thks Tins

Replaced a failed led lamp with identical and it tested OK with the old incandescents it is in parallel with.

I now think the reversing light problem is likely a warn gearbox switch.

The brake light problem has gone away as quickly as it appeared. Turned out to be a dicky crimped connector which I must have bumped when chasing the reversing light problem.

Oldie