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Blinking Battery Light

New 10/10/05

If the battery does not have enough juice to start the car then the first thing you have to do is completely recharge the battery. This will take at least 6 hours, over-night on a self-regulating charger is the best.

At the end of the recharge the amps going into the battery should be under .75A High amperage when fully recharged is an indicator of poor battery condition and it's time for replacement. This is also very dependant on the charging equipment too. Some aren't very good and some are great at regulating charge rate when the battery is fully charged.

Then you check the voltage once it's been setting for at least 4 hours with the charger off. ~12.3V minimum. This also depends on battery type. Serviceable cells are lower whereas the sealed cells will be a bit higher.

Install the battery then start the car. Voltage should be at it's highest point about a minute after the car is first started and the engine is running at 1500 rpms. ~14.4V

Next turn on all the electrical accessories, headlights, A/C on max, brake lights and check the voltage should still be ~14.4V

As the battery is recharged, after about 15 minutes of high way driving the voltage will drop. This is caused by the battery reaching it's stable state and temperature, hotter=lower voltage. The voltage should stay above 13.0V under load as the bottom end of service.

To check the MEGA fuse connection see what the voltage is on both sides of it. The + battery terminal, starter cable end, megafuse both sides and alternator rear bolt should all be within 0.1V of each other. If the voltage is lower there is a connection that is not 100%. This will worsen with load. Also the major ground points should read less than 0.5 ohm between the - battery terminal and the starter and the smaller ground near the air cleaner box on the fender.

When idling with a full load the voltage should still stay above 12V. The alternator is not capable of good output until at least 1200 rpm engine speed. As an alternator ages the peak voltage seen will slowly drop. A new regulator with new brushes will usually fix things. If the bearings are bad it toast and needs to be rebuilt or exchanged. But the regulator/brush thing is a breeze to do on the work bench.

Paul Nimz

This (below) from Dave Garber on Bad Battery Vs. Bad Alternator


The generator (GEN) (10346):

With the ignition switch in the RUN position:

With the engine running:

Section 14-02B: Generator, Integral Regulator—Internal Fan and Regulator Type
1997 Taurus, Sable 3.0L (4V) and 3.4L (4V) Engines Workshop Manual

Voltage Regulator

The voltage regulator (VR) (10316):

The generator output voltage will vary with temperature. The output voltage is typically higher in the winter (cold) and lower in the summer (hot).

The voltage regulator will turn the generator warning indicator on for the following conditions:

Refer to Section 14-00 for diagnostic procedures if the generator warning indicator stays on with engine running.

With the system functioning normally:

The generator warning indicator comes on when a problem is detected in the:

Section 14-02B: Generator, Integral Regulator—Internal Fan and Regulator Type
1997 Taurus, Sable 3.0L (4V) and 3.4L (4V) Engines Workshop Manual


Item Specification
Generator (10346) F5OU-AA
Generator Rating (idle/max. rpm) (130 Amp max)
Generator Ratio (gen. crank/rev.) 2.4:1
Regulator Type (10316) Electronic/Integral with Generator
NOTE: The voltage regulator (VR) (10316) is the only internally serviceable component on this generator (GEN) (10346) .



Is voltage drop less than 0.25 V?
Yes No
GO to B2 SERVICE excess voltage drop in Circuit 35 (O/LB). CHECK Alternator Fuse (30A) and connectors in Circuit 35 (O/LB) and SERVICE as required.


Is voltage greater than 1 V?
Yes No
GO to B3 SERVICE high resistance in Circuit 904 (LG/R).


Are all ground connections clean and tight?
Yes No
REPLACE generator. CLEAN or SERVICE grounds as required.


The Saga Continues 10/11/05

Ok, Second NEW ALT installed this past Sunday. Had this one benched tested in front of me at advance to make sure it worked fine. Tested on the bench as perfect. Walked home with new alt (fat man caring a 20lbs alt 1 mile SUCKS let me tell you! lol) Well installed NEW alt and still getting battery light. Finally give up around 9pm after checking lines and running new fuseblock - alt cable.... (6gauge) Decided to take to Generator / Alt shop about 20 mins away. This guy rocked and knew his stuff (Southern Generator in Milton FL if anyone needs something rebuilt or repaired) He tested everything from the fuse block to the alt ... He by passed the fuse block mega fuse and when he went from the alt to the battery the alt kicked in per his meter and was working fine. He told me to take to a "real" electrical shop (car) and have them track down the issues but he wireed up some 10 gauge fuseable link between the fuse block where the alt cable comes from directly to the battery.

WORKED FINE though out the day. Roughly 6 hr of driving / slacking off enjoying the day off and the nice drop in temps (83 deg here yesterday)) Well went to leave the house a few hours later and had to stop the gas to pull out into traffic and right before redline (told you it was pulling out into traffic lol) The freaking battery light came on!!!!!!!!!!!!!!!!!!!!!!!!! Automattly pulled into advance had them check it (sad they know me by name now lol) 8amps coming off the alt ... took to O'Reillys for second opinion and same thing..... WTF????????? Did the hard acceleration burn out the ALT?? or Possibly rock the engine enough to cause the cable to pull just a little lose from the connection at the alt?

Also if anyone has a wiring diagram of where the 2 pwr leads go when they leave the battery terminal ?? I'm taking it they go to the starter and the fuse block ?? its the correct? its there a fuseable link in that line anywhere? I know the mega fuse it good since there is pwr at both post BUT the ALT only worked when we bypassed the fuse block/mega fuse and went straight to the battery..... ?

HELP!!!!!!!!!!!!!!!!!!!!!! Car is not even 2 months old and I have over 500 in it woohooo So bout to pay my 500 deductible on my insurance and have it totaled. lol Man this sucks this is such a beautiful and fast car!

Thanks for any help and all the help you all have provided already.....



OK new update to my wonderful alternator saga. Well after killing another battery from sears (dead cell per them from totally discharging the battery quite a few times over the past 3 weeks.....opps but they replaced it for free) OK well broke down and decided to replace the ALT from Advance Auto Parts (Palladium P778646G) with another one from them, I just figured there was NO WAY I could get 3 bad ALTs in a row right? Well didn't get to find out since they didn't have any in stock even though their online system and store system said it was in stock. Had to fight with the manager to get my core money back then walked the 2 miles to O'Reillys Auto Parts and get another reman from them (ULT 01-3651) For $1 more then Advance and $10 cheaper Core so made money back on switching to O'Reillys! Had them swap the SHO pulley on and walked my 2 miles back home, you know alternators are not that heavy until you walk 2 miles carrying one! lol

Well 25 Min's later had car cranked up and no battery light! WOOHOOO Not to be to over excited I drove it around most of the day and took it to O'Reillys and to Sears to have the ALT and the Battery Checked and everything was good! OMG I'm so freaking excited that its working!

Spent the rest of day taking the new battery I bought on Friday (day I killed the sears battery) back to advance then went to local junkyard (http://www.butlerautorecycling.com/upullit.htm) and paid $3 for a alt core out of a windstar and returned that for my Core charge. =-)

I want to thank you all on the list and off the list that sent me very good info.

I'm not going to get to super excited about the newly installed ALT working for a while BUT its great knowing I don't have to be home before the damn street lights come on anymore! Drove with the high beams on last night and the AC ON! Man I've missed AC! lol



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