Flickering headlights and dash under light cornering

[jgbrooks]

Hi folks. New 'speed3 owner, red 2007 GT, and love the car. Was a tad skeptical at first as a lifelong classic Chevy nut, but glad I got it - fun, fun, fun. It developed a personality quirk a few weeks after I bought it, though, and I'm hoping someone has a tip. In short, the headlights and dash lights "click" off in right turn directional changes, like in a sweeping right curve going up a hill at freeway speeds, which is a little unnerving in pitched darkness. I can induce the problem pretty much at will at the same sweeping, climbing right handers on my commute. It's also happened in falling right turns at lesser speeds, but much less frequently. Here's what I've observed: with the stalk in AUTO, headlights will go out completely and dash will go into OFF mode (brighter orange but no blue accents). In the ON position, headlights stay on but dash goes into OFF mode. If the stalk is in OFF position (during daylight, of course), the headlights will come on, but the dash doesn't appear to change (hard to tell though in the daylight). In all cases, it's accompanied by a relay clicking in the passenger side of the dash, as if behind the glove box. Outside of the circumstances described above, the car behaves normally; no funkiness beyond the rare DSC/ABS engagement when it's cold. I'm its third owner, and I know that the first owner had installed a pair of Xentec HID boxes, which the second owner removed along with a "fancy alarm system" because his batteries kept going dead. I didn't notice the problem in the first couple weeks, and voltages all look good, which I would expect given that the issue has some specific criteria to meet while driving before it will greet you. Intuitively, I'd suppose that there's a wire or harness somewhere that's grounding or shorting upon moving a certain way when the car is pulling light G's in a certain direction, then rights itself immediately upon coming just back left, but I haven't a clue where to look or what for, exactly. Any wisdom to share with me on the subject? Related side note - anyone want a Xentec kit with a couple pair of bulbs cheap!? Haha, thanks much!

 

[jgbrooks]

To clarify, this happens only while going up or down hills in a right turn (on ramps and off ramps, for example), but most frequently while climbing. Also, "flickering" isn't the best description for what the headlights and dash lights are doing; they momentarily go completely dark and come back on once I straighten the wheel out. No ideas?

 

[spdjnke]

I would be checking for pinched wires or a strained wire connection. since it's only on right turns...take the steering colum apart turn the wheel to the right and see if it pulls on any of the wiring...I'm assuming someone has messed with it, maybe a turbo timer installed at one time or another and they just cut off the wires and it's shorting on something....just a guess of course.

 

[jgbrooks]

Figured it out. While cleaning battery terminals, checking grounds, and wiggling things to see what might move in an uphill right turn, I noticed that the worm clamp holding the cp-e Xcel intake coupler to the turbo inlet pipe had its shoulder buried pretty deep into a portion of the primary wiring harness just beneath the ECU. Closer inspection revealed frayed electrical tape and a highly polished finish on the worm clamp shoulder, and so removed the intake coupler and wedged a thin mirror in between the harness and inlet pipe, shined a bright light at it and lo and behold, shiny copper showing thru 3 adjacent little color coded wires. I had considered pulling the ECU and unraveling some tape to identify which wires were being shorted, but the color coding looked headache-inducing and there was no guarantee I'd learn anything useful, so I cleaned the area with electrical cleaner, made sure the wires were't damaged beyond the insulation being worn away, and applied several layers of high temp liquid "vinyl tape". Naturally clocked the worm clamp counter clockwise so the shoulder was well away from the harness (comfy gap now) and the issues I described have not occurred since. Lessons here are to give parts that need to move independently of one another plenty of clearance to do so, stainless steel is an excellent conductor, and shorting 3 wires at the main harness across each other makes funny things happen. I'm just thankful the harness wasn't badly damaged - yikes.