I have the pin style glow plug kit for my 77 300d but am conceptually unclear on a few issues. I understand the old plugs and grounding strap are to be removed and new plugs installed, but the wiring from the plugs to the vehicle is unclear to me.
It looks to me from the directions, that all the existing system is bypassed, the new timer wired directly to the battery and into the fusebox. This bypasses the heavy 80 amp fuse. Is this correct?
When I bought the kit from Foreign Automotive Parts, I was told I would need an additional relay for my vehicle, but there is no mention of it in the directions. Does anyone know if I really do need this additional relay and how it is wired in?

With the existing glowplug system bypassed, does the wiring into the fusebox result in the key actuating the new timer and heating the glowplugs? There is no explanation in the Bosch paperwork of how this new system works once installed. There must be an existing timer of sorts somewhere in the system, is this being bypassed somehow or is the relay I was sold intended to take the place of the existing timer? If so, where is the existing timer on a 77 300d?
As you can see, I am confused.

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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