Hey first time on here dont know if anyone can help but any info to help would be greatly appreciated so my moms bf has an 06 Silverado thats been acting real funny for the past month or so he just got this truck 6 or 8 months ago maybe no issues at all till recently fter u start it up the headlights will pulse along with the interior lights not on and off completely just enough to notice the change in brightness and at random times the service air bag service 4wd and service brake system messges all take turns flashing across the message center and it starts dinging like u opened the door but forgot to take the key out of the ignition. Sometimes it lasts a few mins sometimes it does it the whole time you're going down the road and sometimes it doesnt do it at all. When the dinging starts and the messges start popping up on the dash the pulsing in the lights stops. The check engine light is on when tested the code that comes up is for the evaporative emission system vent valve/solenoid circuit. Would this cause all these different problems or would it be something else? Dont know much about it myself just trying to help him out. Thanks for any info that may help.

 

The check engine light code for the EVAP solenoid has nothing to do with this. My truck has had that code for years, and runs fine.

What you are describing sounds like an electrical issue. Back in the day, any time I had a voltage regulator go out, I would notice the headlights would brighten and dim with engine speed. Older cars that was a separate replaceable item, but since the 80's they have built the regulator into the alternator. I would do two things:

1. Check the wiring under the hood, make sure everything is tight and clean, including any ground straps you can find, battery cables, etc.
2. See if a local auto parts store can test the alternator on the vehicle.

Another thing to tell him to do is keep an eye on the VOLTAGE GAUGE on his dash, and note if the voltage is fluctuating when these issues occur. That would explain the lights, and also could trigger computer related malfunctions. A typical voltage when the engine is running should be a steady value around 14V on that gauge on the dash. If it is moving around at all while the engine is running, that's a problem.

 

.Thank u ill let him know. Im pretty sure the voltage guage and even the oil pressure guage fluctuates while everything else is goin crazy. When all this started happening he was out and about put it in 4wd due to bad winter roads and about 1/2 a mile down the road he pulled over and shut it off because it was sluggish all of a sudden (no power) and wasnt driving like it had been before putting it in 4wd and all the service messages started popping up and the dinging started. After he shuts it off wont start back. Notices the voltage guage is bottomed out so he gets a new battery fires right up has plenty of power like before but still service messages popping up and a dinging that u hear in ur sleep if u drive it very far.

 

I would check the alternator first, then dig into wiring issues.