1995 concord not charging battery

Discussion in 'Concorde' started by Joust, Oct 7, 2003.

  1. Joust

    Joust Guest

    i have a 1995 concord that is not charging its battery. the alternator nut
    reads 40vdc. i even tried a new alternator with the same results.
    it starts and runs fine so the ASD relay is most likely good. This leaves me
    the PCM.....
    how much are they?
    what a stupid place to put a regulator....
    can it be anything else?
    Joust, Oct 7, 2003
  2. Well, let's start from the start, here, before we go condemning the
    voltage regulator.

    First, check for codes. There are diagnostic flash codes for the charging

    To check the computer codes:

    With the engine off, switch the ignition key on-off-on-off-on,
    leaving it "ON". Do not
    go to "start", just "on" during this procedure.

    Watch the "Check Engine" or "Power Loss" light. It will turn on, then go
    off, then will begin to flash-out any trouble codes that have been stored.
    For instance, if it flashes:

    flash <pause> flash flash
    <long pause>
    flash flash flash <pause> flash flash flash flash flash
    <long pause>
    flash flash flash flash flash <pause> flash flash flash flash flash

    Then you have a 12 (one flash followed by two) a 35 (three and five) and a
    55 (five and five). 55 means "end of codes" or, if by itself, "No codes
    stored. Check the codes and report what you find.

    Are you quite sure you're seeing "40VDC" and not 40mVDC on your meter? If
    you truly had 40V at the alternator output, you'd be broasting batteries
    and popping bulbs and computer components all over the car.

    What else could it be other than the SBEC (you said "PCM")? Could be a
    wiring fault, could be a faulty original alternator replaced by a
    typically garbageful "remanufactured" alternator.

    And in the end, if you run through all the tests and find the voltage
    regulation function in the SBEC has failed, you have several options for a
    cost-reduced fix: You can get a used SBEC with a quick search on
    www.car-part.com . Or, if you're reasonably electrically knowledgeable and
    have some basic electrical repair tools, you can install an external
    voltage regulator rather easily. On a '95 you must also install a resistor
    across the original field wires to fool the SBEC into not setting a
    charging system fault code and tripping the Check Engine light, but this
    is a minor additional effort.

    Go do some diagnosis; if installing an external regulator becomes
    necessary, instructions will be forthcoming.

    Daniel J. Stern, Oct 7, 2003
  3. Joust

    Bill Putney Guest

    I had the same reaction to the 40VDC reading. Follow Daniel's advice,
    but I'd be interesteed to know what voltage you measure at the battery
    with the engine off (IOW, if it's not in the 12V range, then the meter
    is not reading what you think it is.

    Do you maybe have a grounding problem?

    Bill Putney
    (to reply by e-mail, replace the last letter of the alphabet in my
    address with "x")
    Bill Putney, Oct 7, 2003
  4. Joust

    Joust Guest


    Thanks for the detailed reply. I'm sure it will be very helpful and much

    So I double checked my voltage reading. It is indeed 40v DC but t is at the
    alternator lug. NOT the battery. This should be before the regulator and I
    expect it to be high. This would be consistent of a unregulated dc source
    with no load I'm sure. Could be wrong though, I'm not the expert.

    I took it for a spin until the engine light came on.

    Stopped and did your procedure.

    The code that flashed is 124755

    Any ideas?

    Wiring looks good.

    I put a second ground jumper on to be sure.


    Joust, Oct 7, 2003
  5. Joust

    Neil Nelson Guest

    Code 47: Charging voltage low.
    Measure the voltage -at- the battery with the engine running.
    Voltage drop the alternator output to battery wire.

    Sounds like there's an open circuit between the alternator
    output and the battery.
    Neil Nelson, Oct 7, 2003
  6. Joust

    Mr. Elbe Guest

    from the Shop manual:

    12 - Battery Disconnect - Direct battery input to PCM was disconnected
    within the last 50 Key-on cycles.

    47 - Charging System Voltage Too Low - Battery voltage sense input
    below target charging during engine operation. Also, no significant
    change detected in battery voltage during active test of generator

    55 - End of codes

    Looks like you are having an open circuit from the Alternator.
    Mr. Elbe, Oct 7, 2003
  7. Joust

    Steve Guest

    No, this leaves you with a broken connection between the alternator B+
    terminal and the rest of the electrical system. The PCM is obviously
    telling the alternator "charge" or you wouldn't see 40 volts there. What
    is not happening is current flowing from the alternator to the battery.
    Steve, Oct 7, 2003
  8. Joust

    Joust Guest

    this alternator does NOT have an internal regulator.
    for some god awful reason of design ingenuity the designers decided to put
    the regulator circuit inside the Power train control module.

    I'm off to trace the wires and connections to the PCM.
    Joust, Oct 7, 2003
  9. Listen to what people who know are telling you: There is an open between
    alternator B+ and battery +!

    Daniel J. Stern, Oct 7, 2003
  10. Joust

    Steve Guest

    WHY? That is NOT where the problem is!

    You have sub-normal voltage at the battery. You have FORTY VOLTS at the
    alternator! You have a BROKEN WIRE between the alternator and the
    battery. The PCM is doing what God and its designers intended- telling
    the alternator to charge like mad because its sensing low voltage at the
    battery. And the alternator is complying, sending its output voltage WAY
    up there. But with a broken connection, current cannot get to where it
    needs to be.
    Steve, Oct 7, 2003
  11. Joust

    Neil Nelson Guest

    I realize that.
    And it appears to be working...
    FWIW, inside the PCM is a much more forgiving environment
    than inside the alternator case.
    Well, knock yourself out, but you should probably check to
    see if you also have 40 volts -at- the battery terminals,
    since you haven't mentioned an exploded battery, I can
    pretty much guarantee that there isn't.

    IOWs, don't let the trees block your view of the forest.
    Neil Nelson, Oct 8, 2003
  12. Joust

    Joust Guest

    please excuse my ignorance guys. I'm into electronics but i cannot make a
    whole lot of sence out of automotive electrical drawings. there is too much
    information missing.

    so a question.
    should the bolted lead comming from the alternator be a dierct short to the
    battery plus terminal?
    it is supposed to go to a fusible link (whatever that is) to the power
    distribution panel. then to the battery
    Joust, Oct 8, 2003
  13. Joust

    Joust Guest

    sorry Steve,
    I did not see your first reply.
    you sounds very much correct. I appologize for not paying attention to you
    in the first place.

    now where would they hide that fisible link????
    would i tbe safe to say that there shoudl be a direct short from the Bolt on
    lead at teh alternator to the Battery Positive terminal?
    that would provide the charging voltage?
    Joust, Oct 8, 2003
  14. Joust

    Neil Nelson Guest

    That only happens on Japanese vehicles.
    The term "short" implies that there is an unintended problem,
    (short to ground, short between feeds, etc.).
    The alternator output stud is almost always directly
    connected to the battery positive.
    100% of the time, the correct test procedure would be to
    connect one of your VOM leads to the alternator output stud
    and the other to the battery positive terminal, start the
    engine, there should be NO MORE THAN .2 (two tenths) volts
    read on your VOM. Any reading higher than that indicates
    high resistance in the circuit that you've parralled with
    your VOM. Very simple, very basic.
    A "fusible link" is a section of wire in series in the
    circuit that is usually a given wire gauge smaller (at least
    two, but can be more) than the circuit in question, this
    section of wire (fuse link) is covered in a Hypalon coating
    so that if it overheats and blows as a fuse would, there
    will be no flame or fire that can spread to the rest of the
    wiring harness (Hypalon doesn't burn).
    A fuse link is nothing more than a fuse that is not quite so
    easily replaced, and it's done that way for a very good
    reason (being, when they burn open, you have a serious
    problem that negates just plugging in another fuse).
    Have you checked the underhood fuses?
    Neil Nelson, Oct 8, 2003
  15. Joust

    Steve Guest

    Perhaps because when its inside the PCM it usually lasts the entire life
    of the car? Failed regulators in the hot, dirty, vibrating environment
    of the alternator case are common, failures of the Chrysler PCM
    regulator are NOT common. In fact, more alternators are probably
    replaced because of failed internal regulators than because the
    alternators themselves have failed.
    Steve, Oct 8, 2003
  16. Joust

    Steve Guest

    Yes, the B+ terminal normally is a direct connection to the battery
    terminal through the wiring harness. I'm not actually sure if your car
    has a fusible link in that path, or if it has one of the oversized fuses
    (located in the under-hood fuse box as opposed to the in-cabin fuse box)
    in that path. Maybe Neil or someone who's fixed that problem before can
    point you the right way, but I'd pop the cover off the under-hood
    fuse/relay box and look there first.

    You can also start tracing the wire back from the alternator toward the
    battery. Its a heavy-guage wire and should be relatively easy to follow
    in and out of various wire bundles.
    Steve, Oct 8, 2003
  17. Joust

    Neil Nelson Guest

    Agreed totally...

    But you've attributed to me the words of another.
    Neil Nelson, Oct 8, 2003
  18. Joust

    Steve Guest

    Neil Nelson wrote:

    OOps. I knew better, too. :p
    Steve, Oct 8, 2003
  19. Joust

    Joust Guest

    I have to hand it to you guys.
    Daniel, Neil and Steve. you all had it pegged.

    I found this morning with your help that the fusible link was indeed open.
    i jumpered it with a 30A fuse in series and the system worked perfectly for
    about 30 seconds, then it poped that 30A fuse.
    i took it to a Crysler dealership. I put on the work order that I suspected
    the fusable link was open. they worked on it (i saw three of their so-called
    experts working) for 3 hours at $85 dollars per hour. After that, they came
    to me with the news that they thought there was an partially open circuit
    between the alternator and the battery and it would take some time to find
    the problem............I lost confidence in the experts here.
    i explained that i knew that and that i told them and put that on the work
    order...they asked me if i would authorise them to continue working with the
    meter running at $85 per hour....ahhhhhh NO. easy answer.
    they put it on the charger so i could get home. after an hour i found out
    the hard way that they had run it out of gas while testing. Why they needed
    to run it that long i couldn't tell you. it had 1/4 tank when i brought it
    in. by this time the night shift had moved in. The experts were gone home.
    The night mechanic seemed to have a head on his shoulders. i had a chance to
    chat while waiting a bit. he was intrigued by the problem. he did a bit of
    poking and some huh-uh_ing he proclaimed that the computer was not doing
    things right. it was driving the alternator to full output all the time.
    He candidly recomended that i put on an external regulator and even
    recommended a place that would do it.

    you told me that "if installing an external regulator becomes necessary,
    instructions will be forthcoming"
    Is this offer still valid?
    Is there an off eth shelf regulator that i can get or do we resort to home
    brew. I can do the home brew type.

    You guys have been very helpfull. I appologize for my ineptitude and your
    forbearance in this matter.
    I am getting it but am a bit thick.
    Joust, Oct 9, 2003
  20. NAPA Echlin VR38, it'll be in stock.
    Also get an Echlin VRC38 connector plug -- usually special order, so call
    tomorrow AM.

    1) Remove your existing field wire assembly from the alternator. This will
    require some cleverness, as it's part of a moulded assembly that includes
    the two side-by-side flag terminals that are the field terminals, and the
    larger ring terminal that is the output terminal. The output terminal must
    stay, but the flag terminals must be removed from the two studs on the
    back of the alternator. Do not damage the flag terminals!

    2) Using an ohmmeter, measure the resistance across the two studs on the
    back of the alternator. Write down the result. You will need to obtain a
    resistor of approximately this value and place it between the two flag
    terminals to fool the computer into thinking it's still in control of the
    alternator. Use a resistor robust enough to withstand 4A current. Insulate
    (wrap, etc.) the flag terminals and resistor assembly so that they do not
    short to anything else. Do this carefully -- neatness and thoroughness

    3) Your VR38 needs to be mounted to a sturdy surface that won't get too
    hot. Try for a firewall or fender location. It also must have a good base
    ground, so if you are unsure, run a wire from one of the regulator
    mounting screws to the alternator's housing ground terminal.

    4) Your VR38 has two electrical terminals, and your VRC38 connector has
    two wires.

    The terminal/wire that's at the "top of the triangle" needs to go in TWO
    directions: To a source of ignition switched +12V, and to one (either) of
    the field studs on the back of the alternator. Wire carefully and neatly
    and make sure you don't overtax any existing circuits.

    The terminal/wire that's on the right side of the triangle goes to the
    other field stud on the back of the alternator. Wire carefully and neatly.

    And...that's it!

    Daniel J. Stern, Oct 9, 2003
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