Flickering lights

[solli5pack]

coming back to this, did you actually pull the fuse box top off and inspect or just inspect the upper fuse area?
with all that other corrosion showing I would really suspect there to be at least some on the fuse box pins as well

I had the entire fuse box off...looks good underneath

 

[Doubeleive]

I had the entire fuse box off...looks good underneath

are you able to replicate the flickering?
like can you turn the headlights on and heater or something and make it happen while parked? or is it completely sporatic

 

[Doubeleive]

i'm asking because you might want to try and see if you can find the "source"
like I would get a meter and connect the ground to the battery post and the lead to the alternator output and monitor the voltage, the move to the battery positive post and then to the 1st end of the mega fuse, then to the other side of the mega fuse and so on...... and see where it changes if possible.
basically troubleshooting it section by section.

 

[solli5pack]

are you able to replicate the flickering?
like can you turn the headlights on and heater or something and make it happen while parked? or is it completely sporatic

It's constant and gets worse with increasing RPM's..Its a thousand times better after cleaning the corrosion and replacing battery cables but still noticeable. Goes away completely when disconnecting the alternator by removing the two pin plug on the back and running off of the battery.

 

[solli5pack]

i'm asking because you might want to try and see if you can find the "source"
like I would get a meter and connect the ground to the battery post and the lead to the alternator output and monitor the voltage, the move to the battery positive post and then to the 1st end of the mega fuse, then to the other side of the mega fuse and so on...... and see where it changes if possible.
basically troubleshooting it section by section.

Done that like 10 times...everything checks out fine.

 

[Doubeleive]

It's constant and gets worse with increasing RPM's..Its a thousand times better after cleaning the corrosion and replacing battery cables but still noticeable. Goes away completely when disconnecting the alternator by removing the two pin plug on the back and running off of the battery.

ok so I know you replaced the battery cables, have you replaced or tried bypassing the charge cable from the alternator to battery positive?

 

[Doubeleive]

have to tried doing the same with a meter on OHM's and taking the reading on the ground cables, while the issue is happening if is it not on the power side then one would presume it is on the ground side.

 

[Doubeleive]

I'll just add I had a not the same but similar issue on the silverado, really screwy electrical issue the radio would cut off and on, cluster would flicker, heater would turn on/off, tons of errors like brake error, service this/that errors. etc
tried dam near everything one could think of to fix it, dealer even replaced the cluster and pretty much could not find the issue.
I finally gave up and told the dealer to put there best tech on it and don't call me till you find it.
took the tech2 about 2 hours with a oscilloscope to find that my alternator was throwing 800ma electrical "burst's" and this was causing the bcm to think the ignition was being cycled and just causing all kinds of havoc.
not saying your issue is the alternator but it might take a scope on it on various sections until it is found.....
if that electrical short is faint enough you might not see it with a regular meter

 

[solli5pack]

I'll just add I had a not the same but similar issue on the silverado, really screwy electrical issue the radio would cut off and on, cluster would flicker, heater would turn on/off, tons of errors like brake error, service this/that errors. etc
tried dam near everything one could think of to fix it, dealer even replaced the cluster and pretty much could not find the issue.
I finally gave up and told the dealer to put there best tech on it and don't call me till you find it.
took the tech2 about 2 hours with a oscilloscope to find that my alternator was throwing 800ma electrical "burst's" and this was causing the bcm to think the ignition was being cycled and just causing all kinds of havoc.
not saying your issue is the alternator but it might take a scope on it on various sections until it is found.....
if that electrical short is faint enough you might not see it with a regular meter

I was thinking maybe a scope might be neccessary. I have had a total of four different alternator's on the truck so I do think that's it. My Yukon is pretty rusty underneath including the engine block so I'm wondering if somehow that's connected to the issue.

 

[solli5pack]

When I get some time I'm gonna do some testing on the charging system with the Tech 2 and see what comes up.