Im no expert and may very well be talking out of my Auto Start Stop, but you may be correct if it's a simple SPDT switch. But if the ECU is checking or expecting to always see it in it's default "on" position, it may be throwing it off or going into some sort of protection mode.
If the...
Useful thread. Thank you for posting information for future folks.
I was considering doing this with my 22 basesquatch. I ended up going the route of aftermarket. I went this way for simplicity, greater amp ratings and switch count. I choose a solid state option over a traditional...
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It's nice to see guys discussing more of the technical side of things.