[mtc]

Figured I'd post it since I'm not sure it's common knowledge...

09 Cobalt LS, 2.2 Ecotec LAP. I'm investigating some P0010 problems and dug into the wiring a couple weeks ago to check everything out. The wiring is not the issue (I suspect a bad oil change record) but I discovered something rather interesting anyway. The slot marked "Engine Valve Solenoids" in the fuse box is actually a blank; i.e. putting a fuse there will not connect anything. The VVT solenoids are actually powered off of the same circuit as the sidemarker bulbs (labeled "parking lights") on the fuse box cover. This circuit receives its power from a miniature relay soldered onto the printed circuit board inside the fuse box. That relay, in turn, is controlled by the BCM.

I didn't believe it at first, but it seems the wiring was just a bit of an afterthought at GM in this case...

 

[hellship]

Thanks for sharing. And just when I thought I've seen the best of GM and its infinite wisdom

 

[MP81]

Kind of like how the cruise control and the third brake light are wired together. Our Cruze diesel had issues with the cluster constantly turning on and off (along with the HVAC), as well as the infotainment screen fuse constantly blowing...all caused by shorted out side detection sensors in the rear bumper.

Cars these days (not even just GM) have some occasionally strange wire routings.