My sister's truck gets this awful flickering of everything that lights up, dash/gauges, headlamps, etc.
This is a bone stock truck.

Awhile back the alternator and battery crapped out so she took it to Sears to have it replaced, the flickering happened after she took it to Sears which is why I'm guessing it's something they did.
She took it to Jiffy Lube for an oil change and they didn't know what it was, so she took it back to Sears and they said it was fine..uh ok.
So then she took it to a friend who works at a Chevy dealer and he cleaned up battery acid that Sears didn't when they changed out the battery.
It still flickers, should she just change the alternator and battery? I don't want to deal with Sears, but I guess we'll see what they do.
When she gets back I'll see what brand the alternator and battery are, I think the battery is a Die Hard

 

Sounds like a connection problem to me. But who knows?

 

sounds like a bad voltage regulator, if you have a tester set it to 12v and touch the output terminals of the alternator, it should be putting out a constant voltage then test at the batt. posts. if you don't have one most auto parts stores will test them for you they should also be able to tell you if the voltage reg is built in the alt or external.from what you said, it would make sense that the reg is external and may have been the original cause of the failure, if it is sending erratic voltage to the battery and either over or undercharging it, it can cause both of them to fail but they should have checked for that when they changed them. if you find that either the battery or the alternator is defective, get the parts store to write you a note with their findings. then take it back to sears and tell them to either fix it or reimburse your money. i've stayed away from sears since i saw a consumer reprt thing about them reshelving returned batteries. i don't know if you've dealt with them before but i've had good luck with 4 wheel specialties on sepulveda [not 4wheel parts- they suck] dwayne is the owner, he seems like he knows his stuff. and i've never felt screwed. good luck.

 

Ed... you can have my stock 105A alt if need be. I'll talk to ya later tonight and help diagnose this. I'll be on around 10pm my time..

Eric :Chug:

 

Thanks guys. I checked the connections on the alternator, everything fine. It's an AC Delco alternator, however, I don't know which one. Does AC Delco make alternators that put out less than the stock 105A ones?
The battery tray is all rusted and I talked to the friend at the chevy dealer, he said he cleaned out a huge acid leak and that the battery terminals were all corroded. The problem still exists so I think my sister will just take it to the dealer and see what they say, then go back to Sears and bitch if it's a problem that they caused.