Hello,

I just recently purchased a 1980 MB 300TD, really beautiful. It's a bit chilly in the NE USA right now, and it idles rough. Decided to ohm test the glow plugs. I found that there were 7 wires/posts on the relay, not 5 as I was expecting. There seems to be an additional connection between cylinders 1&2 and 2&4 (first forward couple and second forward couple), a hex key blank between 4&5 (3rd forward couple), and then a heater line between 5&3 (rear-most couple).

When I ohm test them, it's bizarre which is which. One on the relay does correspond to glow plug for 1, but also for cyl 3?? and 2 on the relay is to the sensor(?) between 1&2, and I can't really figure out what is going on with the others. Do I have the wrong relay in this car? PN on the relay box is 001 545 78 32. What are those sensors? Quick googling seems as though it should have relay PN 001 545 98 32?

Thank you! I'll post some pictures of the car in a showcase topic sometime soon.

Vincent

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1980 MB 300TD
1975 Jeep J10
1975 DAF 66 Marathon Coupe
1965 DAF Daffodil 31