The light is just an idiot light, more of a recommendation based on the ambient temp. The relay will run the full cycle no matter if its freezing or a hundred and five, at least on the older models, like non-cdi's. Its only the timing of the light that changes with temperature. I'm assuming you're asking this about your '85, which will not have an afterglow feature built into the stock relay, meaning that as soon as the relay senses the starter engaging, the gp's kick off. I'm not sure if an afterglow relay can be purchased for the 123's or not. The plugs will always be on at full power when they're engaged, no half power setting.

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Seth

1984 300D 225K
1985 300D Donor body
1985 300D Turbo 165K. Totaled. Donor Engine. It runs!!!
1980 300SD 311K My New Baby.
1979 BMW 633csi 62K+++? Dead odo