Haven't had time to troubleshoot this, but I thought I'd throw out the symptoms to keep me away from any dead ends. 1981 300D, 200K: 1. Started and drove car twice in AM yesterday. 2. Sat for 3.5 hrs and then was completely dead- no starter action, no lights, interior lights work, some dash indications, all dying when cranking attempted. Chattering coming from glow plug relay. 3. Given the totality and suddenness of these symptoms, I'm wondering about a short that just happened during this short interval of rest. 4. Tried jumpering - no response, and the cables got warm at the source vehicle. 5. As car was in downtown Seattle and would have been towed, I got it home as is. 6. Are these symptoms of the warned-about voltage regulator going south? My second guess would be the starter, or something in the circuit that would drain the battery at rest and short out a jumpered input. Thanks, pebermynte