Got an '05 XC 90 which has been throwing error messages up intermittently for apparently no good reason. Tells me to check the stop lamps, and they're fine. Tells me the tailgate is open, but it's not. Dome light comes on when these error messages come on. They seem to be triggered by hitting bumps in the road but they also come on when starting the car. Not sure if this is a wiring problem or a switch problem (and I realize they're the same system but they're two separate pieces) and was wondering if anyone had any experience with chasing down this brand of gremlin? Dealer checked the fuses as a "courtesy" but wants $$ to really get in there and maybe diagnose it and I'd much rather DIY this if possible. If anyone can point me in the right direction of where to start looking, it would be greatly appreciated. TIA!

Two separate items. The stop lights warning should only come when your foot is on the brake. I suggest taking both of the bulbs out of the rear bulb holders and check for corrosion, and, clean both the bulb and bulb holder to see if that makes a difference. Replacing both of the bulbs is also an option, never replace just one bulb.

The dome light coming on and the rear hatch message could well be an adjustment problem on the rear hatch. 'Closed' to your eyes might not be closed to the micro switch inside the latch. Try spraying a little white lithium grease or WD40 on the latch mechanism and see if that helps. The dealer will normally change the entire mechanism and charge accordingly, usually over kill.

If your rear hatch is slamming down, you might start thinking about getting new replacement struts for it. The constant slamming creates a lot of stress on the lock.

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