tail lamp gremlins

I'm having trouble with the right rear turn indicator on my 89 Range Rover. It works perfectly until I apply the brakes or switch on the headlamps, at which point every bulb in the cluster except the indicator flashes. Also, if I apply the brakes with the headlamps on, the tail light goes out when the brake light comes on. Has anyone out there encountered this problem? Thanks

it sounds very much like a bad earth. you need to clean up all contacts especially the earth contact to the body.