Third brake light wiring

[torquewrench]

Hello chaps,
I need to pick your brains again, how do I and wire up a third brake light to my 1995 W202 diesel?. I have tried to splice it into the brake light wiring near the rear offside cluster with the earth bolted to the body. The light does not operate it only blows the brake light fuse. Can anyone please advise, thanks

 

[bigasotonuk]

Fit a relay, with the coil fed from the existing brake light feed, and run a fused feed directly from the battery through the N/O contacts of the relay to the new brake light.
Double check you have the brake light feed and not inadvertantly picked the wrong one.

 

[torquewrench]

Thank you Andy for your quick response, many thanks