bypassed the ambient light sensor. Hooked up a 680 ohm and 10k ohm resistor to a relay harness. Triggered relay with trailer parking light fuse in fusebox. (the fused side, terminal furthest from cab) though im not sure if 18 gauge wire is enough to pop the stock 15A fuse, or if my wire would burn up with short) I might add a tap and put a smaller fuse in, though the wire is loomed up and in safe locations..
View attachment 401663
red wire (30 terminal) goes to the white wire in ambient light sensor (i de-pinned it and heat shrunk the wire on it in case it didnt work)
blue wire went to brown park lamp circuit (fusebox in my case)
all other wires are grounds, but two (87a and 87 terminals) with resistors soldered inline and a bunch of heat shrink to keep them from stressing the resistor leads.
no more dimming in the daytime, adjustable dimming at night.
UPDATE: One weird behavior.
When turning lights off, the dash display goes from nighttime dim, to off, then on daylight bright.
Does not cycle off when going from daytime to nighttime.
Not sure why, maybe the sudden change in voltage going from 10kohm resistance suddenly to 680ohm is too fast for the BCM to adjust?
That or some other electrical behavior I don't understand.. Any suggestions on how to wire a fix?
Reading up on something called a flyback diode.. something about voltage spikes when power to coil is cut, which would make sense why it happens turning lights off.
Ordered a relay with diode, but I'm not sure that's the issue.
also swapped my 85 and 86 (coil terminals) around. Sounds like conventionally 85 is -, and 86 is +.