Take five strands of solid copper wire cut from romex, strip both ends of each. Stick one end of each into the glow plug harness after it's unplugged from the relay, twist the five other ends together and run a jumper wire from that twisted group of five over to the positive post on the battery.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13