Jump to content

need Help crazy battery light and service charging system issues. 05 z71

stlucas
 Share

Recommended Posts

stlucas Enthusiast

stlucas

Posted
Posted

I’ve seen a lot about this same issue but no answers or fixes. I have an 05 Sierra crew cab z71 w/103,000 miles. This issue has got me stumped. truck runs fine but when you crank it & set for a minute the battery light comes on & display says service charging system. If you crank it & drive the battery light will come on say setting at an long stop light or driving slow in a parking lot. The battery is good the alternator is good. I do notice when the ac fan is on high the blower speed will increase & decrease when the voltage gage increases & decreases. i’ve checked all the grounds & they are good. It seems to happen when the voltage drops & right before the alternator is signalled to produce voltage/charge the battery, the battery light turns on. I disconnected the battery control sensor  to see what it would do(someone mentioned doing) That caused the battery light to come on soon as the truck was started. I found a video were it mentioned the service  charging system display & battery light. video was of a hummer and under the fuse panel under the hood there is a wire that gets damaged causing this problem. They didn’t specify what wire or how to test for that wire. Also saw a video wasn’t any help were guy just says its the battery control sensor. the battery control sensor is around the negative cable at the battery. Maybe a coincidence but this issue started about 1 1/2 years ago about week or two after i jumped my brothers truck off. When jumping his truck off his ground wire to his frame was loose & tightened it. I also have an hypertech programmer & returned the stock program back to the truck to see if that made a difference. It didn’t but noticed that when clearing the codes and putting the hypertech program back on my truck during the install of the program the instrument display said reduced engine power then went away. now redoing the program it displays briefly reduced engine power when ever i try reinstall of the program. truck runs fine and everything seems to be working. just can’t figure out what would cause the battery light & service charging system to show up randomly. was looking for a way to test the battery current sensor? also if anyone has any idea of the wire that is under the fuse panel is that maybe the issue. if anyone knows what the fix is for this please let me know. i know i’m not the only one. thanks all & GOD BLESS 

davester Senior Enthusiast

davester

Posted
Posted

What did you do to verify that the battery and alternator are good?

When you checked all the grounds, what did you do to each one?  Did you do anything to the power side?

Perhaps get the codes read with a really good code reader (something like a tech ii, or autogenuity w gm enhancement, or something similar, that can read codes from all the computers in the truck)?

  • 1 month later...
stlucas Enthusiast

stlucas

Posted
  • Author
Posted
On 7/30/2020 at 12:38 AM, davester said:

What did you do to verify that the battery and alternator are good?

When you checked all the grounds, what did you do to each one?  Did you do anything to the power side?

Perhaps get the codes read with a really good code reader (something like a tech ii, or autogenuity w gm enhancement, or something similar, that can read codes from all the computers in the truck)?

Put a meter across the grounds the point at the battery & checked the chassis end & the block end. cond good, resistance, good, voltage drop good. Have a Battery tester at work and it’s checked out. Alternator is putting out the correct voltage following the specs of how the charging system works. didn’t happen for 2 weeks then bam happened the other day. When it happened i unhooked the battery control sensor, thats  around  the negative cable, then plugged it back & battery light & service charging system display went away. I see people posting this same issue but no one gives an fix. 

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.

  • Forum Statistics

    250.4k
    Total Topics
    2.7m
    Total Posts

  • Member Statistics

    342,759
    Total Members
    8,960
    Most Online
    DM22
    Newest Member
    DM22
    Joined

  • Who's Online   2 Members, 0 Anonymous, 2,743 Guests (See full list)

  • Latest Articles

  • Posts

    • dna9656
      No low range 4 x 4

      By dna9656 · Posted

      My 2015 1500 LTZ Silverado suddenly won't go into 4 x 4 low. It will go into 4 x 4 high.
    • asilverblazer
      Transmission Woes :-(

      By asilverblazer · Posted

      Yep, just a quick reference point.    My main point being I’d do a thousand other things before I’d pay 10k for a transmission.    Speaking in ignorance cause I don’t look at these trucks, what is it worth? 20k?
    • asilverblazer
      Intermittent no-code issues on 2022.5+ V8 trucks — what did the shop fail to capture?

      By asilverblazer · Posted

      I think users are going to want to pick their monitored parameters, which parameters they want to see first.    It should probably start with baseline at a minimum and adjust to learned, but be able to overlay baseline for comparison.   A simple severity level would be able to determine what type of alerting is appropriate or user selectable.    Why not use the OBD port though?   I think a phone connection would be a good idea, push notifications type deal.   Number 1 issue is having data is useless if you don’t know what the data should be under normal conditions. 
    • Chuck FB
      summer road trips in the 2026 2500HD

      By Chuck FB · Posted

      I thought I would use your thread and add to it as I just did my first longer drive with my truck in the last couple of days. I drove from the Grande Prairie area of Alberta down to Edmonton and most of where I drove in the city was the ring road so fairly free flowing but a bit of stop and go as well in the city. Stayed the night and returned home and not too many stops along the way each way but every restart and certainly every cold start sets it back for fuel mileage. Why I say that is I see some people will cherry pick a fuel mileage leg after the vehicle had been warmed up driveline wise before hand and its a forgiving ( easy rolling drive leg for example ) and call that their fuel mileage which can give a false perception of reality. I was not heavily loaded at all but never the less the flip bak cover, rubber bed mat, various tools etc and extra jerry cans of fuel all way up to a few hundred pounds of dead weight so its not an empty truck. The cold inflation tire pressures are set more near the freezing point so once they are warmed up driving I was showing 45 front and over 40 rear and realize high inflation pressures would help a little in fuel mileage but certainly not the ride on our crap sections of highway. The weather was good so was not raining as that can really drag mileage down, in fact I had a bit of a tail wind on average driving home. Most people on here would never have driven on that freeway to visualize it but its got a fair bit of rolling type of landscape with numerous river valleys. For the most part I had it on cruise set to 62 although kicking it off if I caught it in time before it started down shifting and self braking going down the grades. Most of the more substantial grades its shifting into 7th I believe as 8th just doesn't have it. Total distance round trip was 643 miles and my overall average and I did refuel three times in all, figured out to 17.65 miles per US gallon. My best fuel mileage section refuel within all of this figured out to 18.46 and these are all hand calculated figures. I find if anything that the trucks computer can be over optimistic, sometimes its pretty close but other times its stretching it. On paper persay in theory the truck would have just about made it on fumes for that whole drive without refueling once.    Which made me think of the topic thread of the wonder if these trucks could do 20 mpg and that is a good question, certainly would have to be on an easy going flat highway, no head wind, the right temperature, not packing around a bunch of dead weight and puttering along even slower than I was I would suspect and going steady and not stopping to smell the flowers or take a piss !. It probably is possible but not without effort to attain that with the wind resistance and weight of these trucks. Of course on my drive most people are passing me if they have the power as per loaded highway tractors, never mind a lot of speedy vehicles but the speed limit is 68 and most are at or well over that. 
    • Aimatdeer
      Ac not keeping up

      By Aimatdeer · Posted

      Monday looks like a good day for the dealer to test an ac issue. Hopefully it all turns out good.

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...