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need help with flickering headlights!!!

Discussion in 'GM Electrical Tech' started by redneckarmyMP, Aug 30, 2012.

  1. The Heater

    The Heater Member 2 Years 100 Posts

    Make sure you save the instruction sheet for that battery. I have the Optima Yellow Top for my truck. If you drain the battery too low, you have to hook up a lead acid battery in parallel and then attach the charger to the lead acid battery until you get a certain voltage reading, after which you can hook the charger directly to the battery.
  2. PantheraUncia

    PantheraUncia Active Member 2 Years 1000 Posts

    I had flickering before I had my hid kit installed. I started going away when I put the new alternator in and upgraded to 2 yellow op batteries under the hood.

    I was also told that you could replace "The Big 3" meaning the main 3 battery cables in the truck by going with a heavier gauge wire than what the stock wires are.
  3. The Heater

    The Heater Member 2 Years 100 Posts

    The only wire you need to think about altering is the wire going from your alternator to your battery. You could make it larger like 8 or 4 gauge, if you had put in a larger output alternator. Your other battery wires should work fine.

    And you don't need two batteries unless you are running off road and have a winch, or are running other external accessories like in a camper or travel trailer (but the latter would have its own batteries). The OEM battery in a deep cycle version should work fine for main stream accessories. I am running three amplifiers in my truck and I am not using a second battery or a power cell. No problems at all. And running a trailer with lots of lights and dual axle electric brakes was also not a tax on my battery or alternator, which is 170 amps (which is certainly not a super gonzo alternator).
  4. PantheraUncia

    PantheraUncia Active Member 2 Years 1000 Posts

    I thought the stock GM alternators were 105amp and 135amp, 170 seems like an upgrade? I was thinking about a 250amp, or dual 250 am alternators.... its not about what I have in the truck now, is about what i am adding on later. :)

    And while that second yellow top may not be needed for normal use, it did smooth things out with the electrical in my truck.
  5. SurrealOne

    SurrealOne Former Member ROTM Winner 1000 Posts

    If memory serves the alternate/larger size is 145 amp?
  6. PantheraUncia

    PantheraUncia Active Member 2 Years 1000 Posts

    For my Truck:



    105amps is the standard and 135 is what they install as "heavy duty" on a 1500

    For you 2004 Sierra:



    105 is the standard and 145 is the heavy duty

    On a 2010 Silverado 1500:



    145 is the standard and 160 is the upgrade...

    I am seeing a pattern here....

    It would be nice if they just put 250 amp alternators in and called it a day, unless it need a dual upgrade or something like an ambulance, etc.
  7. The Heater

    The Heater Member 2 Years 100 Posts

    My truck came with a 100 amp alternator. I had one built in the OEM case that has higher output, thus the 170 amp unit.

    My point is simply that you don't need to overthink your electrical. If you put in two AGM batteries, you now have double the charging load. If you don't have a need for it, why put it in if it is just going to be asking your alternator to recharge it?

    If you upgrade to a 250 amp alternator, one deep cycle battery can work for whatever you have going on, short of say a large winch or electrical from a camper or something similar.
  8. Need Mo Tools

    Need Mo Tools New Member

    I had this issue on my 99 Tahoe. At first I also was looking at the grounds and battery cables. I have never been a fan of the side post terminals. I cut the red plastic boot off of the positive cables and separated the two positive cables discovering a lot of corrosion between them. I cleaned the cables and with a longer cable bolt from Advance Auto I put them back together with a crown washer between the two cables and between the cables and the side of the battery. I corrected my intermitent start issues but did not correct the headlight flickering. I traced the headlight to the alternator, bearing failing emitting red rust dust throughout the alternator causing arching. I suppose it was really messing with the the internal voltage regulator. I had been hearing the rumble of a bearing failure however I was thinking the belt tensioner was failing. I replaced tensioner and still heard the noise and then noticed the red rust dust coming out of the alternator. I replaced it and solved the problem. It has been fine ever since. I think a lot of starter motors have been replaced because of these side post cables and when you get corrosion between the cables the starter cannot get enough amperage to spin the starter.
    Good luck.
  9. The Heater

    The Heater Member 2 Years 100 Posts

    Yellow Top Optima is what I am using.
    1 person likes this.
  10. Skippy

    Skippy Member 2 Years 100 Posts


    Great information. Excellent post to keep others aware. I appreciate you following up with the solution!

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