Wish I could change the main title of this post. It seems confusing now.

Thank you for the advice about the pre-relay connection causing resistance.

I guess what is happenning is that although I have voltage, I do not have enough amps to keep the glow plugs happy.

Has anyone ever bypassed/replaced the hot wires that feed the relay ?

I hate having a non-standard/stock car, but at 30 years old the wires
are getting hard, probably breaking down a bit.

The wires themselves could be part of the problem.

Anyone ever run a bypass line to feed the relay ?

Thanks everyone.

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80 300D 340K Owned 30 yrs
83 300SD 440K Owned 9 yrs - Daily Driver 150mi/day
02 Z71 Suburban 117,000
15 Toyota Prius 2600 miles
00 Harley Sportster 24k
09 Yamaha R6
03 Ninja 250