I have 99 venture that has no tail lights or dash lights. the running lights work until the headlights come on and the running lights go out and the tail lights don't come on and all we a have the headlights. I have checked the fuses and checked the boards in the rear lights I didn't see any burnt marks or anything is there something else I should be looking for. Can the board be bad without showing signs? is there anyway to test them?