Hello all I have an interesting issue going on. My wife told me that on occasion the headlights and the dash lights will blink when she lets off the gas. Well last night on her way home from school she said it was happening a lot and really made her nervous. Today I checked the battery and alternator and both are good. After setting all night the battery was bouncing around 12.5 to 12.6. The alternator with no load is putting out 14.5 volts. Also I checked all positive and negative connections and all are tight. With the lights on the ac on and in defrost mode the alternator is putting out 14 volts. I could not replicate the lights flashing. I am going to drive it to work tomorrow to see if I can replicate the problem. Any info will be much appreciated. Thanks in advance. Side note the BCM was replaced in October.

 

The BCM plug is the first thing I'd check if I were you. It sounds like it's either loose or has some corrosion in it. Disconnect your battery ground cable and then try unplugging and plugging the connector back in several times. This will help to "sweep" the contacts clean. After you do this, hook the ground cable back to the battery and see if that helps. If not, I'm guessing you may have a funky headlight switch.

 

I forgot to mention that it has been doing this sporadically for years. But its always few and far between but apparently got really bad last night. 'll look into the bcm plug. Am I correct in assuming that it's behind the glove box?

 

I'm not sure where it is on your car. I'm used to finding them behind the passenger side kick panel on most vehicles, but I'm more familiar with Mopars than GM products.

 

Ok thank you ill look for it this weekend. I drove it to work this morning and it happend one time. Ill continue to monitor it. I googled it and it seems like its a common problem with the l200 and a lot of people took went to the dealership and were told its normal.

 

I'm going to take a wild jump and suggest you check the tensioner and belt -- sounds kinda like the belt is slipping on the alternator pulley ...........

 

I applogize for the late response. The belt tensioner and belt are in perfect shape. There is no evidence of the belt slipping. I found out that my wife was only driving the car 1 day a week maybe 40 miles round trip for school. After we started driving the car more consistently the problem seems to have stopped. I havent had the time to sweep the BCM plug but If it starts back up again I will let you know. Thanks again for all the help.

 

That may turn out to be something you never figure out. Be sure to stay active here, or you'll have to register again if it starts acting up.

 

Just wanted to give an update on the problem. It seems to have gone away. Im not sure if its because we drive it more or its just one of those gremlins that likes to show its ugly head. Ill keep you guys posted on what happens. Thanks again for all of your help

 

Enjoy your ride, keep the oil at the proper level, and make sure the tires are inflated properly. It should last you a long time ....