Spoiler brake light

[MRBILLYUK]

Strange problem this.
I'm replacing the led pcb in my spoiler brake light.
I have 12 volts coming through the wires in the spoiler. The replacement led pcb works when I plug it into a 12 volt supply in the house.
When I connect the wires together, the leds don't come on and the voltage drops by about

half to 6.5volts 🤔

I'm no electrician so haven't got a clue why this is happening.
I wonder if anyone could shed some light on this problem?

 

[Louis]

You've a high resistance somewhere.
Car engine on, brake pedal pressed in?

 

[MRBILLYUK]

You've a high resistance somewhere.
Car engine on, brake pedal pressed in?

Yeah. Engines on and brake pedal pressed in. The 2 normal brake lights are working just the spoiler won't light up.

 

[Mr Trailer Man]

You've a high resistance somewhere.
Car engine on, brake pedal pressed in?

Could be high resistance in those solder seal connectors?

 

[Louis]

What amps it drawing on the power supply?

 

[R3k1355]

Bad earth somewhere, it's always some fucked up rusty earth point.

 

[MRBILLYUK]

Could be high resistance in those solder seal connectors?

They worked with the last led board I had it in there. It only failed because it got wet so I cut the wires off the failed led board so I had more to work with when I came to replace it. It was a bit of a t**t to solder them because the wires aren't very long, they're almost inside the spoiler.
I might have to desolder them and use the new wire on the new led board.

 

[MRBILLYUK]

What amps it drawing on the power supply?

I haven't had time to check today. I'll have a look tomorrow if it's not pissing down 👍

 

[MRBILLYUK]

Bad earth somewhere, it's always some fucked up rusty earth point.

Where would the earth be for the spoiler? Any idea?