CX battery light glows at night
  • Register
  • Help
Results 1 to 8 of 8
  1. #1
    Fellow Frogger! marc61's Avatar
    Join Date
    Jul 2013
    Location
    Stamford, UK
    Posts
    331

    Default CX battery light glows at night

    I get the battery light glowing dimly when a fair bit of load is connected at night. Headlights, blower, radio and wipers are enough for it to glow faintly - it goes out if I switch the wipers off. I've just been and swapped the alternator for a good spare and still the light comes on!

    Advertisement


    At idle I'm measuring 14.5V across the battery and with everything switched on 13.1V. Car starts from cold fine, so don't suspect the battery or the alternator now. Battery positive and earth leads and connections are all good. Beats me. Any suggestions appreciated.

    Marc
    Cheers, Marc.

    1987 CX GTi T2 Maikonics
    1972 SM 2.7 carb
    1972 DS21 EFI

  2. #2
    Now go make me a sandwich Hotrodelectric's Avatar
    Join Date
    Nov 2010
    Location
    San Diego, California, USA
    Posts
    3,534

    Default

    How old is the alternator? I would suspect the brushes are pretty worn. This will cause a weak output.

    Try all this first: go through the wiring, especially at the front left corner behind the battery and make positively sure all grounds are attached to clean metal and tight. Check the connections at the alternator and (if your CX is old enough) at the regulator. If there is a ground strap for the alternator, it MUST be attached. Check both ends of the battery cables.
    The measure of your character isn't what you do when people are watching- it's what you do when they aren't watching.

  3. #3
    Real cars have hydraulics DoubleChevron's Avatar
    Join Date
    May 2000
    Location
    Ballarat,Vic,Aust.
    Posts
    16,428

    Default

    you'll probably find this is normal behavior. I'll have to see if mine still does it now I've replaced the starter cables, alternator cable, earth cables etc.... I imagine the answer will be *YES*

    seeya,
    Shane L.
    'Cit' homepage:
    Citroen Workshop
    Proper cars--
    '85 Series II CX2500 GTi Turbo I
    '63 ID19 http://www.aussiefrogs.com/forum/citro%EBn-forum/90325-best-project-car-you-have-ever-seen.html
    '72 DS21 ie 5spd pallas (last looked at ... about 15years ago)
    '78 GS1220 pallas
    '92 Range Rover Classic ... 5spd manual.

    Yay ... No Slugomatics


    Modern Junk:
    '07 Poogoe 407 HDi 6spd manual

  4. #4
    Fellow Frogger! marc61's Avatar
    Join Date
    Jul 2013
    Location
    Stamford, UK
    Posts
    331

    Default

    Have established the alternator brushes are fine, battery connections are fine and I cleaned up the main earth, all cables are good. But it still glows in the dark when lots of stuff is switched on, whether the car is idling or driving along. Its very dim and flickers a tiny bit, but I cant make it any brighter by switching everything on. Its not bright enough to see in the daytime.

    I'm thinking it's trying to tell me the alternator voltage is below the battery voltage, at worst I'm measuring 12.9/13.0V across the battery with everything on and the engine idling. Guess it must take a very small voltage difference to illuminate the light.

    Maybe it's an early sign that the battery is on its way out - if we get any proper winter weather here I guess I'll find out one cold morning.

    Would be interested to know if yours still does it Shane.

    Cheers

    Marc
    Cheers, Marc.

    1987 CX GTi T2 Maikonics
    1972 SM 2.7 carb
    1972 DS21 EFI

  5. #5
    Contented Peugeot Driver addo's Avatar
    Join Date
    Jun 2005
    Location
    Don't remind me!
    Posts
    16,609

    Default

    Are you sure the rectifier pack is OK?

  6. #6
    Real cars have hydraulics DoubleChevron's Avatar
    Join Date
    May 2000
    Location
    Ballarat,Vic,Aust.
    Posts
    16,428

    Default

    Quote Originally Posted by marc61 View Post
    Would be interested to know if yours still does it Shane.

    Cheers

    Marc
    Works brilliantly ... quite literally. I tested all the electrics before I fitted the radiator/fans/condenser/etc back into the nose, and everything worked perfectly. Obviously now it's back together I fired it up to bleed the radiator then gas up the A/C ... and jumped in the car to put everything on full bore to check the A/C pressures .............. To find a nice shiny bright charge light on .... sigh .... Oh well, at least the charge light works well

    seeya,
    Shane L.
    'Cit' homepage:
    Citroen Workshop
    Proper cars--
    '85 Series II CX2500 GTi Turbo I
    '63 ID19 http://www.aussiefrogs.com/forum/showthread.php?t=90325
    '72 DS21 ie 5spd pallas (last looked at ... about 15years ago)
    '78 GS1220 pallas
    '92 Range Rover Classic ... 5spd manual.

    Yay ... No Slugomatics


    Modern Junk:
    '07 Poogoe 407 HDi 6spd manual

  7. #7
    Fellow Frogger! marc61's Avatar
    Join Date
    Jul 2013
    Location
    Stamford, UK
    Posts
    331

    Default

    Quote Originally Posted by addo View Post
    Are you sure the rectifier pack is OK?
    Yep. I took the alternator off, took it apart, unsoldered the rectifier bridge and took it off to check each diode. I've just done the same for the one that was originally on the car and guess what its diodes are fine too! The brushes were a bit more worn and it needs new bearings, but basically I've got 2 good alternators here. Both are Paris Rhone.

    Think I'll get the battery out of my XM tmrw and connect it up to see if that solves it.
    Cheers, Marc.

    1987 CX GTi T2 Maikonics
    1972 SM 2.7 carb
    1972 DS21 EFI

  8. #8
    Real cars have hydraulics DoubleChevron's Avatar
    Join Date
    May 2000
    Location
    Ballarat,Vic,Aust.
    Posts
    16,428

    Default

    I'm still pretty certain this is normal behaviour for a CX. I just noticed your in the UK. I'd be more concerned about the wiring being full of black rot than the alternator itself. Have you checked the wiring from the wiring from the altnerator across to the starter? It gets cremeted and covered in road salt down there (especially if it's turbo charged). Check for resistance and black rot in the main battery cables too. I'd just replaced all of this with solder on heavy duty connectors. I even solder the main battery cables to the new battery terminals (those bolt down/crimp down brass battery terminals tend to just squish the shit out of the wire, eventually allowing the cable to work it's way out of the battery terminal).

    Also pull your spare wheel out and the shroud under it. You'll find a bunch off connector blocks where the engine harness plugs to the body harness. These will need replacing on a salty, soggy pommy car. Good luck with that ... You'll end up meters deep back into all the wiring harnesses trying to find sound wire to solder the replacment wire too.

    Salty soggy UK wiring versus normal wire:



    This CX was imported into australia way back in the mid 90's too.

    seeya,
    Shane L.
    'Cit' homepage:
    Citroen Workshop
    Proper cars--
    '85 Series II CX2500 GTi Turbo I
    '63 ID19 http://www.aussiefrogs.com/forum/showthread.php?t=90325
    '72 DS21 ie 5spd pallas (last looked at ... about 15years ago)
    '78 GS1220 pallas
    '92 Range Rover Classic ... 5spd manual.

    Yay ... No Slugomatics


    Modern Junk:
    '07 Poogoe 407 HDi 6spd manual

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •