Mercedes Vito with cycle carrier - NO TAIL LIGHTS

[Steham]

Hi folks,

Have a problem which had been driving me mad for months!!

Really need to get my cycle carrier lights working on my Vito towbar socket.
Have a 7 way bypass relay, and can get every light working, apart from tail lights!!

Have tried everything I can think of, nothing!
White wire is earthed on left hand side of 7 way relay, and towbar socket is earthed on the white wire too.

No tail lights....have checked wiring to the terminals in both halves of the towbar socket...no ideas!!

Please someone help meeeee!

 

[ruston]

Take it you have wired both tail light wires to respective connections in bypass relay ? Also check that your trailer board tail lights are not common. (linked together ). If so try one trigger only ,disconnect the black, or separate the link.
Also check the continuity of the trailer board wiring.

 

[Steham]

Take it you have wired both tail light wires to respective connections in bypass relay ? Also check that your trailer board tail lights are not common. (linked together ). If so try one trigger only ,disconnect the black, or separate the link.
Also check the continuity of the trailer board wiring.

The socket on cycle carrier has separate wires for each tail light, so they're separate on the bypass relay too

 

[ruston]

Do you get any readings at the tail light terminals when they are switched on? Are the earths ok at the lamp holders ?
Is there output at the relay connections when switched on?
Have you used Scotch locks to tap into the loom?