Alternator Issue after LED install?

Discussion in 'Engine & Drivetrain' started by Z71 Dude55, Nov 5, 2018.

  1. Z71 Dude55

    Z71 Dude55 TYF Newbie

    Posts:
    5
    Likes Received:
    1
    Joined:
    Nov 5, 2018
    Name:
    Grant
    I have an 03 Tahoe Z71 and just recently installed a few LED lights, 4 in total. I ran two of them on one harness, and the other two on separate harnesses for a total of 3 harnesses. I ran all three to the battery and after driving for about 30 minutes, the "Battery not charging" and "service brake booster" messages intermittently came off and on for the whole drive. Once in awhile it would go back to normal but wouldn't last more than a few minutes. My voltage dropped from 14 to about 12 and slowly just went lower and lower until the battery died. I'm not sure if the battery has been replaced or if the alternator has been replaced but before I change those, I want to see if there is a different solution. I read through other posts but couldn't find much on my specific issue. I don't know much about electrical so that's why I'm asking.
    Any help would be appreciated. Thanks!
     
  2. Z28TWITCH

    Z28TWITCH Member

    Posts:
    75
    Likes Received:
    23
    Joined:
    Sep 18, 2013
    Name:
    Twitch
    Need a lot more information. What kind of leds...like, lightbars, headlights, driving lights? relays, fuses, switches? worked on or around anything else? sounds like your battery connection is junk... but i have no where near enough information to diagnose whats going on.
     
  3. Z71 Dude55

    Z71 Dude55 TYF Newbie

    Posts:
    5
    Likes Received:
    1
    Joined:
    Nov 5, 2018
    Name:
    Grant
    Sorry, One 52 inch light bar, one 22 inch light bar, and two 4 inch pods. They are all on relays with 20amp fuses and have separate switches. I didn't touch anything else, just connected my lights via the relay harness + switches all to the battery. I'm not sure if my alternator is 105amp or if its a bigger like 145. Battery is something like 860 CCA.
    Not sure if its a coincidence but this problem only started happening after the lights were all installed and I installed them all at the same time. Before this, the voltage always read at 14+

    [​IMG] (3 of these just wired to the battery) the 2 pods are connected to just one harness + switch. The other two light bars have their own harness + switch.
     
  4. Z71 Dude55

    Z71 Dude55 TYF Newbie

    Posts:
    5
    Likes Received:
    1
    Joined:
    Nov 5, 2018
    Name:
    Grant
    I also tried removing the light connections from the battery and running it like normal but got the same result, just draining the battery, no charge while driving.
     
  5. Lancem

    Lancem TYF Newbie

    Age:
    62
    Posts:
    13
    Likes Received:
    7
    Joined:
    Oct 23, 2018
    Location:
    West Texas
    Name:
    Lance
    Bad alternator, it was probably on it's last leg and adding the lights just happened to push it over the edge.
     
  6. Z71 Dude55

    Z71 Dude55 TYF Newbie

    Posts:
    5
    Likes Received:
    1
    Joined:
    Nov 5, 2018
    Name:
    Grant
    Ok, yeah I went ahead and scanned it this evening and received a P1637 code for "Generator L terminal circuit" However no check engine that might come with a faulty PCM. I also checked all connections and grounds and they were tight. So I think I will order a new alternator and im sure youre right that it will solve the issue. Thanks for the help.
     
    Lancem likes this.
  7. Rocket Man

    Rocket Man Sometimes A Dumbass

    Posts:
    8,376
    Likes Received:
    10,229
    Joined:
    Dec 25, 2014
    Location:
    Oregon
    Name:
    Mark
    Yeah those lights should have no effect on the alternator unless they’re faulty.
     
  8. Z71 Dude55

    Z71 Dude55 TYF Newbie

    Posts:
    5
    Likes Received:
    1
    Joined:
    Nov 5, 2018
    Name:
    Grant
    So you don't think the alternator is the issue? What exactly is the P1637 code for "Generator L terminal circuit" ?
     
  9. Rocket Man

    Rocket Man Sometimes A Dumbass

    Posts:
    8,376
    Likes Received:
    10,229
    Joined:
    Dec 25, 2014
    Location:
    Oregon
    Name:
    Mark
    I didn’t say the alternator isn’t the problem, I do not know if it’s bad. I just meant a few led bars isn’t enough of a load to cause an alternator to go out.
     
    Last edited: Nov 7, 2018
  10. Rocket Man

    Rocket Man Sometimes A Dumbass

    Posts:
    8,376
    Likes Received:
    10,229
    Joined:
    Dec 25, 2014
    Location:
    Oregon
    Name:
    Mark
    Any updates?
     

Share This Page