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I've got a 2008 Chevrolet Cobalt. The passenger front blinker, passenger rear blinker & brake light, and the middle brake light are all out. The hazard lights also do not work on the passenger side.

I've looked at all the fuses I can find that remotely deal with lights in the floor panel & under the hood; no visual issues. I've looked at all the bulbs themselves, and none of them seem busted.

Does this sound like an electrical short somewhere? Maybe the turn signal switch? I don't really know where to start or where to look to diagnose the issue. Any thoughts?

Damon Bauer
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Take a look at the wiring diagram below. The important clue is you said the middle brake light isn't working.

The CHMSL (Center High Mounted Stop Light) works only from closing the dedicated relay. This signal provides power to the lamp, and also instructs the engine and transmission control modules that you are braking.

Unfortunately, this function is provided solely from the BCM (Body Control Module). If that module is bad, it can affect many things - including the CHMSL and the passenger side signals.

If the module is indeed bad, it will be an expensive repair - and involve a special "Tech" GM tool to program your vehicle's specific information.

Alephzero's comment is a good one; I would check the shared ground paths (you can see them as dotted lines in the diagram). However, I doubt the FRONT and the rear share the same ground path, which leads me back to a BCM issue.

Identify the CHMSL relay in the underhood fuse block, and have someone feel it while you pump the brakes with the car on (not running). It should click everytime you hit the brakes. If not, that's bad news and points to a bad BCM.

Good luck.

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SteveRacer
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