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Getting code p1637. What to replace?

Discussion in 'Chevy Trucks' started by CashinH&P, Dec 29, 2014.

  1. CashinH&P

    CashinH&P Senior Member
    Messages: 448

    The battery light in my 04 chevy came on, and would flash. The display screen says "battery not charging". I would assume that means replace the alternator. I hooked up the code scanner and it says p1637 Alternator L terminal Circuit. Googled that and not really getting a clear answer, any one have an idea? Or is it as simple as I thought and just replace the alternator?
     
  2. leolkfrm

    leolkfrm PlowSite.com Addict
    Messages: 1,403

    check it for charging at the battery with a volt meter, may be a fault with the internal regulater, it sends 2 signals, one to guage and one to computer for warning light

    mine stopped charging put in rebuilt and light was on, changed it again and all has been good for 4 yrs
     
  3. chevyzrule810

    chevyzrule810 PlowSite.com Addict
    Messages: 1,238

    Most likely it is an alternator.Check and make sure the connector on the alternator is good and tight and free from any corrosion
     
  4. chevyzrule810

    chevyzrule810 PlowSite.com Addict
    Messages: 1,238

    You can also remove the alternator bring it to autozone have them test it to see if it is any good,and if it is you already have it out.
     
  5. CashinH&P

    CashinH&P Senior Member
    Messages: 448

    Alternator was junk replaced and good to go thanks guys
     
  6. chevyzrule810

    chevyzrule810 PlowSite.com Addict
    Messages: 1,238

    Nice glad to hear
     
  7. Plowtoy

    Plowtoy Senior Member
    Messages: 929

    If the battery has not been replaced recently, you might consider replacing it now too. Seems that once one goes, the other is not far behind. I cant tell you how many times at the dealer I would replace a battery or altornator (even if the other tested good at the time) and a week later, the customer would come back and be needing the other. Just my $.02
     
  8. chevyzrule810

    chevyzrule810 PlowSite.com Addict
    Messages: 1,238

    My battery is almost 3 years old and the truck still has its original alternator 2006 2500hd with almost 80,000 on it