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Chevrolet Cavalier 2004 Wiring Problem Solution

My daughter was having intermittent problems with the headlights on her 2004 Chevy Cavalier. In short, they sometimes worked, sometimes didn't; sometimes using the "brights" shut them off completely. Sometimes when you started the car, they'd flick on and off seven or eight times and then not work. Or work. There was no rhyme or reason. I thought it was a wiring problem because I'd seen them flicker, so I knew the bulbs were good. I checked first to see if it was a fuse but it wasn't (which made sense). In short, it seemed to me to be a wiring problem--somewhere between the headlights themselves and the firewall. I explained this to the dealership and then angrily demanded my daughter's care back and refused to pay any money after a week and what was approaching a $600.00 bill. They gave in (Yay ME!) and after a little research I discovered that this model uses a lighting arrangement wherein the bulbs turn on as "running lights" when the transmission is engaged (but not in "Park."). Basically, the bulbs themselves have three settings: "running lights," "low beam," and "bright." After consulting with an automotive electrician and trolling some auto-repair discussion groups, I discovered that Chevy's wiring geniuses routed between 14 and 21 wires into what is called a "pin-out connector" that ends up being directly beneath the battery. Batteries leak so over time, so these pin-out connectors (which function as a result of the manufacturing process, not for any reason that helps the lights actually work) get corroded. I asked a friend to simply cut the connector out and splice in new, longer wire to restore all the connections. Which he did. For $25.00. Took all of 30 minutes. Best thing? Took the melted pin-out connector to the dealership the next day to share my find and the service manager (an older gentleman) asked to keep it to use as a "learning" exercise with his young mechanics. He told me that GM would NOT have allowed the repair as I had it done; would have forced the dealer to buy their replacement and the repair could have topped $900.00. I reported this episode to my brother-in-law who has a fully restored Corvette and he said they had the same design flaw. This should have been a re-call because light failure (plus dash, etc) could be very dangerous under the right ("wrong") circumstances. If you have experienced similar problems with older model Chevy's, look directlty under the battery housing to see if a rectangular piece of corroded/melted plastic with a bunch of wires going in one end and coming out the other is the culprit!

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Try changing the bulbs. No. They didn't both burn out at once. You probably drove for a while with one headlight, and didn't know it.

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check headlight relay

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