The relay has some minor intelligence and it senses resistance and current draw if I remember correctly in each plug among other things. During acceleration, the plug will heat up from the energy of combustion and increase the resistance measurement. The sensing circuitry may be returning a "false positive"of plug condition or actually detecting a fault in one of the plugs.

One other thing first, You mentioned you checked voltage to each plug with a DVM--check resistance, cold they should be in.4~.5 ohms, warm .6~.7 ohms.

Pull the larger 6 pin plug from the top of the relay and ohm out each plug--takes ten minutes.

The light on after start is a "check glow plug integrity" light so to speak.

I've included the condensed versions of chapter 15 from the 602-603 shop manual. The last page talks about fault detections.

Ensure you plugs are 100%, and if they are it's the relay.

Attached Files

	15-0705a.pdf (472.5 KB, 488 views)
	15-0705b.pdf (457.3 KB, 431 views)

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Mark
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