I would like to get some advice on sequential turn signals. I have a 69 hardtop and when i'm driving there is a horrendous buzzing sound coming from the "black box" or the relays in the trunk. the buzzing sound goes away when I apply the brakes and is intermittent when the turn signal is activated. the left rear works like it should, sequentially i mean, but the right does not. only the first light comes on. I have replaced the flasher units and all bulbs as well as making sure all of the relays are grounded. I can't stand the buzzing and I love my car. can anyone please help?