[Intrigued]

My old '83 Pontiac diesel had a big honkin' relay which would engage for about 4 seconds before kicking out, to send power to the glow plugs. It was all automatic,and temperature related somehow. One of the other mechanics at the dealership said that something like 10 seconds would burn out the glow plugs, so I paid attention to the sound. It should be real easy to wire up something yourself, with the idea in mind of how long Benz glow plugs will last before getting zorched...