"Bulb out" light on dashboard when using rear lightboard

[Shaun]

Ok , so far I have tried two different rear light boards on my bike racks, the first a cheap and cheerfull one and the second is built into the Altera tow bar bike rack .
Both times all the lights on the boards seem to work perfectly but after 5mins driving time the "bulb out " light comes on on the dash and stays on.
Any advice great fully accepted

 

[Stu]

Are you using a 7 - 13 pin adaptor??

I had a cheap one before that wasn't up the job and did the same.

 

[Shaun]

I am using an adaptor with the altera rack but not with my original light board.
I seem to get the same problem with or without the adaptor.