When i put my car in drive the indicator dash keeps indicating that My rear left and rear right lights are not working but they do work this has been happening for about 3 months now what is causing this how do i get rid of this no one has given me an answer to this problem is there anyway to fix this without changing the bulbs the bulbs are actually 5 months old

I drive a Audi A4 Cabriolet Someone told me that that its something in the trunk not connecting but theirs thick cables in the trunk that are covered I'm not going to take out my lights just to get nowhere and sometimes my break lights will be on for no reason they'll be on until I press the break

SO please can anyone help me

2005 Audi A4 Cabriolet