PotM GrandMarq.NET - Panther Headquarters Forum Index PotM
GMN Chat Room GMN's STORE!! GMN's Gallery Please!!
Page 1 of 2 12 LastLast
Results 1 to 20 of 36

Thread: Alternator Not Charging Battery?

  1. #1

    Default Alternator Not Charging Battery?

    Car: 1989 Mercury Grand Marquis
    5.0L EFI
    OEM Alternator with External Regulator
    Observed Condition Car is dying while driving or idling. (Lights Dimming, Clock Dimming)
    Apparent Cause: Insufficient electrical energy in the battery to sustain engine operation.
    Background: Condition arose during test drive after recent replacement of heater core and brake line. (Car sat for approximately 5 weeks and is not my daily driver) Battery has been replaced (judged defective by parts store and replaced under warranty) and alternator is new OEM unit with approximately 6,000 miles on it. The engine has been replaced with a rebuilt unit (by me) and around 6k miles were put on the car before the heater core and brake line failed.

    My Analysis: I've had the alternator bench tested and it bench tests ok. It puts out ~14.5 volts at ~800rpm. The battery also bench tests as OK. I've put a multimeter to the battery with the car off and it measures 11.7 volts. (It's not completely charged) The voltage at the alternator with the ignition off is the same. This is grounding to the chassis. Once the car is started, the voltage at the battery drops slightly and continues to slowly drop as the car runs. The voltage at the alternator continues to be the same as what is at the battery. As a result, I have a feeling that the alternator is not taking over and charging the battery. The measured voltage drop as measured directly from positive terminal on the alternator to the positive terminal on the battery is almost zero. I suspected that the alternator may not be ground correctly but I manually ground the small (secondary?) ground on it to the chassis and saw no change in performance.

    I'm now thinking that the external voltage regulator may be causing the problem. I've replaced it with the old OEM unit (It has been replaced before as part of trouble shooting a short circuit after a previous engine swap.) and also saw no change. The only two questionable things that I see are that the plug for the voltage regulator shows some exposed wires. I will check the connectivity today. The only other thing is that there is a coupler between the alternator and voltage regulator carrying two ground wires for which the pins on both sides do not seem to be oriented correctly to ground the alternator. This has, however, not been changed since the engine swap.

    My requests, for the group here are for answers to the following questions:
    Is there some change point from the heater core change (Whole dash came apart) that could affect this condition?
    Is there any more analysis that I can perform before resorting to a professional mechanic? ;-;
    3G upgrade?

    Thanks in advance. -MJ
    Last edited by july7543; 03-15-2009 at 09:56 AM. Reason: Corrections to Spelling

  2. #2
    I post a lot... turbo2256b's Avatar
    Join Date
    Apr 2006
    Location
    MI
    Posts
    2,817

    Default

    Start checking the fuseable links. Open up the wire loom coming into the alternator. Followit up about a foot towards the drivers front fender for one of them. There is also one coming from the starter solinoid follow the wires from it going towards the back side of the headlight / behind and along the side of the battery.. Things could be a bit different but its were to look on a 87
    Last edited by turbo2256b; 03-15-2009 at 11:28 AM.
    Scars are tatoos of the fearless

  3. #3
    I'm an air-conditioned gypsy gadget73's Avatar
    Join Date
    Jan 2005
    Posts
    26,460

    Default

    What he said. There are fuse links between the big plug on the alternator and the plug that stuff connects to on the driver's side fender. When they melt, the alternator has no charge ability.

    86 Lincoln Town Car (Galactica).
    Drivetrain: 5.0 HO, Explorer cam, FMS 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley, SuperCoupe stall converter

    Suspension: Bridgestone Protenza G019 225/60/16 on LSC turbines, 1 3/16" wagon front bar, 1" PI rear bar, cargo coils, KYB GR-2 front shocks, F150 rear air shocks, big front brakes, ES poly front suspension bushings, 00 CVPI steering box, ES poly body mounts, rear disc brakes

    91 Lincoln Mark VII LSC SE, triple black (Timewarp) - poly front bushings, KYB struts and shocks.

  4. #4
    not embarrassed on a scooter 85crownHPP's Avatar
    Join Date
    Sep 2004
    Location
    central VA
    Posts
    12,210

    Default

    Is it that way for the 86+ boxes with the external regulator?? My ex-reg 85 only has one fuse link near the starter solenoid. Regardless, it too could use a check, likewise.

    They say the 'battery' light is critical for alternator function too... has the light come on in the speedo while you are discharging? if not, maybe the filament in the bulb broke while man-handling the dash.

    I had this mystery no-charge problem once - it turned out the stupid small push-on stud connection for the 'excite' one wasnt making a good connection.
    After replacing damn near everything, I gave that little connector a squeeze and put a little electro-grease in it, and it was right as rain. Id check yours out before you do anything else...

  5. #5

    Default

    Currently, at ignition on. I get the low fuel, check engine, engine, and seat belt light to pop on.

    The amp light is not coming on while driving. I disassembled the exterior parts of the dash and checked the the bulb. I connected it to a AA battery and it glowed nicely. I also tried swapping it with a working bulb the same four lights illuminate. I checked the signal to the bulb in the connector and I do see a voltage there. I am going to carefully try some electrogrease in there to guarantee a connection. (While avoiding a short circuit hopefully) If that will trigger the Amp light then I will judge that to be the cause of why the amp light is not coming on. Can anyone confirm with their cars, if the amp light pops on at startup for a 'gauge check'?

    After this, I'm going to investigate the fusible links.

  6. #6
    Fastest Box In South Jersey 86VickyLX's Avatar
    Join Date
    Jan 2007
    Location
    Westmont, New Jersey
    Posts
    9,292

    Default

    Quote Originally Posted by july7543 View Post
    Can anyone confirm with their cars, if the amp light pops on at startup for a 'gauge check'?

    After this, I'm going to investigate the fusible links.
    Yes, mine will light up key on engine off. If it doesn't light at all, there's something wrong. Have you tried checking the voltage at the battery?
    "Vicky" 1986 Ford LTD Crown Victoria LX ..................................."Blue" 1992 Mercury Grand Marquis LS

    Vicky
    Too much stuff to list in my signature...
    Blue
    Mods So Far:
    5.0 HO Swap from 92 Cougar (Courtesy of Lincolnmania, Gadget73 and SVT98t), Electric Cooling Fan, Autodimming Mirror With Compass, Frankensteined but fully functional JBL Premium Sound System, HPP wheels, Working A/C, more mods to come soon!





  7. #7
    I post a lot... turbo2256b's Avatar
    Join Date
    Apr 2006
    Location
    MI
    Posts
    2,817

    Default

    Its a lot easier to check the fusable links first, yes when you turn the ignition to on most of the check lights come on. Thiss is to let you know the bulbs are good.
    Scars are tatoos of the fearless

  8. #8
    I'm an air-conditioned gypsy gadget73's Avatar
    Join Date
    Jan 2005
    Posts
    26,460

    Default

    Check the links. If nothing, check the bulb in the dash. If the bulb doesn't work, the alternator won't charge. There are also connectors at the fender that the wires to the alternator plug into. if those are damaged, or the wiring between the fender and the alternator is damaged, nothing works. The stuff between fender and alt has a habit of melting down under that split loom.

    Pete: seems to change per year. 86 2g has links only at the starter relay. 87+ seems to have links between the alternator and the fender. Those harnesses are different per year too. Not sure about the externally regulated jobbies but I think they may be only at the starter relay.

    86 Lincoln Town Car (Galactica).
    Drivetrain: 5.0 HO, Explorer cam, FMS 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley, SuperCoupe stall converter

    Suspension: Bridgestone Protenza G019 225/60/16 on LSC turbines, 1 3/16" wagon front bar, 1" PI rear bar, cargo coils, KYB GR-2 front shocks, F150 rear air shocks, big front brakes, ES poly front suspension bushings, 00 CVPI steering box, ES poly body mounts, rear disc brakes

    91 Lincoln Mark VII LSC SE, triple black (Timewarp) - poly front bushings, KYB struts and shocks.

  9. #9
    Fastest Box In South Jersey 86VickyLX's Avatar
    Join Date
    Jan 2007
    Location
    Westmont, New Jersey
    Posts
    9,292

    Default

    I remember when I had the instrument panel out of the car, the alternator would not charge the battery. You need to make sure that there's a good connection for that bulb.
    "Vicky" 1986 Ford LTD Crown Victoria LX ..................................."Blue" 1992 Mercury Grand Marquis LS

    Vicky
    Too much stuff to list in my signature...
    Blue
    Mods So Far:
    5.0 HO Swap from 92 Cougar (Courtesy of Lincolnmania, Gadget73 and SVT98t), Electric Cooling Fan, Autodimming Mirror With Compass, Frankensteined but fully functional JBL Premium Sound System, HPP wheels, Working A/C, more mods to come soon!





  10. #10
    Graham: Your source for car repair and smartassery. 91waggin's Avatar
    Join Date
    Feb 2008
    Location
    Portland, OR
    Posts
    1,558

    Default

    91 had links between the alt and the fender.

    to OP:

    Go 3g! Fire hazards are bad news, and your headlights will get brighter.
    Quote Originally Posted by gadget73 View Post
    There is nothing more permanent than a temporary fix.
    91 Mercury CP, Lopo 302, AOD, 3.08LSD. 3g upgrade, Moog wagon coils up front, cc819s in the back. KYB GR-2 police shocks. Energy suspension control arm bushings. Smog deleted.
    93 F-150 XLT, 302, Mazda 5-spd, 4wd. Stock for now
    99 Subaru Forester (wife's ride). 2.5 NA 5-spd. 95 Subaru Legacy Wagon--red--STOLEN 1/6/13

  11. #11
    Mazda5: the Anti-Van! 1987cp's Avatar
    Join Date
    Dec 2006
    Location
    Michigan-ish
    Posts
    5,808

    Default

    So you *have* tried a new regulator?

    We do have 1G wiring schematics posted here somewhere (I made readable versions in MS-Paint back when someone was forgetting to tell us he had an ammeter in the mix), or you can get them out of your Haynes or Chiltons manual.
    2012 Mazda5 Touring | Click below to buy my cool '81 LTD:

  12. #12

    Default Update

    So it would appear the bulb does work. The resistance across it is not open and when connected to a AA battery, it does glow. There is voltage at the connector (~12V) but only about .02A will flow through it. Is that enough? I know that the AA will probably put out more than that for a short period of time. This is suggest to me that I might have a short circuit with something wired in parallel. Should I try shorting the connection that the amp light would be connected to and see if the voltage at the alternator increases?

    In any case, how can I judge the quality of fusible links? Will they completely melt (including the black plastic wrapping) if they go bad? Do I simply measure the resistance across it?
    Last edited by july7543; 03-21-2009 at 05:31 PM. Reason: Correction or poor spelling and grammar :(

  13. #13
    I'm an air-conditioned gypsy gadget73's Avatar
    Join Date
    Jan 2005
    Posts
    26,460

    Default

    Unplug the voltage regulator, and ground the green/red wire. The bulb should glow brightly with the key turned on. If ot doesn't, you've got some sort of wiring issue between the ignition switch, the lamp, and the voltage regulator plug. If it glows, then the problem is with the regulator, alternator, or the harness between the two.


    You can check the fuse links both by looking at them, and with an ohm meter. If they're melted, they're shot. If they look OK, check for battery voltage on the output stud on the back of the alternator to ground and the A terminal on the regulator to ground. If you have battery voltage in both places, the links are OK.

    If you want to isolate the problem, you can do some tests. Unplug the regulator, and measure from the F wire on the plug to ground. You should read between 4 and 250 ohms. Less means a short in the field, more means an open in the field circuit. Since the alternator tests OK, this probably means the wires between the regulator and alternator are the problem.

    If thats OK, with the regulator unplugged, jump a wire from the A to the F terminal on the regulator plug. You should see the battery voltage increase. This is a full field test on the alternator. If you get voltage, the alternator itself is working, and your issue is with the regulator. If nothing, jump from the output stud on the alternator to the F connection on the alternator. If you get voltage, then you have wiring problems between the alternator and regulator. If nothing, your alternator is no good.

    86 Lincoln Town Car (Galactica).
    Drivetrain: 5.0 HO, Explorer cam, FMS 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley, SuperCoupe stall converter

    Suspension: Bridgestone Protenza G019 225/60/16 on LSC turbines, 1 3/16" wagon front bar, 1" PI rear bar, cargo coils, KYB GR-2 front shocks, F150 rear air shocks, big front brakes, ES poly front suspension bushings, 00 CVPI steering box, ES poly body mounts, rear disc brakes

    91 Lincoln Mark VII LSC SE, triple black (Timewarp) - poly front bushings, KYB struts and shocks.

  14. #14

    Default Update

    Thanks to Gadget's and others' help, I have some updated information. I can confirm that both applicable fuseable links are OK. I see voltage at both the alternator and at the A connection on the regulator.

    When I connected the LG/R ground that leads into the cabin, the amp light did light up with ignition on. The coupler that it connects into, oddly enough, does not even have a pin to ground this connection. It looks like it is setup to not ground the light green/red wire at all. I have attached some pictures to try and show this.

    When I jumped A and F terminals on the plug I did see the voltage at the regulator spike. Also, when i connected the positive terminal on the alternator to the F terminal, I also saw a voltage spike.

    Something I did discover is that if I separate the coupler that the Amp light comes into the engine bay from, and ground the orange/black wire from regulator exposed via the coupler, the alternator voltage jumps up to around 15 volts. If, I try to check the resistance of the black wire to ground (the one that meets the orange/black wire in the coupler) to ground, I get an open circuit. If I check the light green/red wire, I can confirm that it is a closed circuit.

    Effectively speaking, I could manually ground the regulator and Amp light ground and it just might work. Something does seem strange about that coupler though. :/
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	DSC00263.JPG 
Views:	162 
Size:	127.4 KB 
ID:	15937   Click image for larger version. 

Name:	DSC00264.JPG 
Views:	187 
Size:	128.7 KB 
ID:	15938   Click image for larger version. 

Name:	DSC00265.JPG 
Views:	162 
Size:	117.9 KB 
ID:	15939   Click image for larger version. 

Name:	DSC00266.JPG 
Views:	158 
Size:	126.4 KB 
ID:	15940   Click image for larger version. 

Name:	DSC00267.JPG 
Views:	173 
Size:	129.7 KB 
ID:	15941  


  15. #15
    not embarrassed on a scooter 85crownHPP's Avatar
    Join Date
    Sep 2004
    Location
    central VA
    Posts
    12,210

    Default



    It looks like some one has been monkeying with your wiring - the pins in those connectors aren't in the right spot to make a connection... if you have some small enough picks you can get the pins out and shuffle them in those connectors. Id match those up and try to find where the loose ends of the wire coming out of that connector should go.

  16. #16
    Mazda5: the Anti-Van! 1987cp's Avatar
    Join Date
    Dec 2006
    Location
    Michigan-ish
    Posts
    5,808

    Default

    Sounds like time to make your own harness with at least 8 AWG for the charge cable.
    2012 Mazda5 Touring | Click below to buy my cool '81 LTD:

  17. #17
    Fastest Box In South Jersey 86VickyLX's Avatar
    Join Date
    Jan 2007
    Location
    Westmont, New Jersey
    Posts
    9,292

    Default

    Quote Originally Posted by 1987cp View Post
    Sounds like time to make your own harness with at least 8 AWG for the charge cable.
    Why go through all the trouble of making a harness for an obsolete alternator. If you're gonna run a new harness, go to a 3G alternator. And buy the pigtail from your auto parts store, and run a brandy new charge cable to the starter solenoid.
    Last edited by 86VickyLX; 03-23-2009 at 02:33 PM.
    "Vicky" 1986 Ford LTD Crown Victoria LX ..................................."Blue" 1992 Mercury Grand Marquis LS

    Vicky
    Too much stuff to list in my signature...
    Blue
    Mods So Far:
    5.0 HO Swap from 92 Cougar (Courtesy of Lincolnmania, Gadget73 and SVT98t), Electric Cooling Fan, Autodimming Mirror With Compass, Frankensteined but fully functional JBL Premium Sound System, HPP wheels, Working A/C, more mods to come soon!





  18. #18
    Mazda5: the Anti-Van! 1987cp's Avatar
    Join Date
    Dec 2006
    Location
    Michigan-ish
    Posts
    5,808

    Default

    Actually, a 2G harness is readily converted to 3G, and vice versa. I'm still running a 2G in the formerly-3G-equipped P72 with the 2G stuff just piggybacked right on (so it can be put back to 3G configuration without cutting).
    2012 Mazda5 Touring | Click below to buy my cool '81 LTD:

  19. #19
    I'm an air-conditioned gypsy gadget73's Avatar
    Join Date
    Jan 2005
    Posts
    26,460

    Default

    The ground at the voltage regulator comes through the mounting screws. There is no ground wire in that flat plug. If you have rust under the mounting screws, it won't work properly. Try pulling the regulator and cleaning that area up with a wire brush.

    The wiring does look sort of bitched up. You can re-wire it fairly easily. F on the regulator goes to FLD on the alternator. S on the regulator goes to S or Sta (i forget how its marked) on the alternator. Thats really about it, the circuit is pretty simple.

    86 Lincoln Town Car (Galactica).
    Drivetrain: 5.0 HO, Explorer cam, FMS 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley, SuperCoupe stall converter

    Suspension: Bridgestone Protenza G019 225/60/16 on LSC turbines, 1 3/16" wagon front bar, 1" PI rear bar, cargo coils, KYB GR-2 front shocks, F150 rear air shocks, big front brakes, ES poly front suspension bushings, 00 CVPI steering box, ES poly body mounts, rear disc brakes

    91 Lincoln Mark VII LSC SE, triple black (Timewarp) - poly front bushings, KYB struts and shocks.

  20. #20

    Default Update

    Well, after taking Gadget's advice. I cleaned up the ground connection to the regulator and I am now seeing 14.5volts of output from the alternator at idle.

    I do now, however, need to work on the fact that the Amp light does not lightup at startup. I will light up if I ground the green/red wire that is in the coupler. However, currently that wire is set up to do nothing. The wiring diagram in the manual shows that there are two wires connected to the amp light negative side. A R/LG and a LG/R wire. One of them is not used. I can only guess that the one that should be used is not being ground. (Or my wiring is no good and that is the one that should be grounded)

    I should note that with regard to the coupler, there are plates at the back that force the wires into the locations that they are in. It is reasonable that the light green/red wire is the one that is not used and that the black wire is intended to run up into the car.

Page 1 of 2 12 LastLast

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
GMN Approved Links!


www.rockauto.com www.adtr.net