Mechanics

FLASHING ALTERNATOR LIGHT

Ford Taurus

1994 Taurus SHO, 3.2L, A-T, 202,000kms

A while ago the Alternator warning light would illuminate when the RPM's were below 1800.
Revving the engine to above the 1800RPM point would see the light go off, and normal operation continued even at RPM's below 1800. At times the light would not come on again, but then reappear sometimes minutes later, sometimes only the next day. At times the lightwould not go off until the revs were over 2500-3000. Semed to be geting worse.
At times in order to keep the light off, I would have to turn off the OD so that the engine speed would increase by 1000RPM's, and thus allow for the light to go off when vehicle speed was low, or in urban situations run the car in 2nd gear(A-T) so as to pick the RPM's up, and get the light out.

Today I had the alternator(Bosch replacement 20 mths ago)bench tested, and all 5 times the test was run, it came back good. I thought it may have been the internal regulator(diodes)problem. Not they said.

Re-installed the alternator, started the car, light was out, but after a while it started to flicker on and off again whilst at normal idle. As it warmed up, it took higher RPM's to get it to go off, as much as 3000.

After allowing the engine to run for a while, the ABS light came on, the Tach dropped to ZERO, the engine died. The car would not restart, as the battery was drained.

Recharging the battery has everything running normally once again. All lights out.

Note that the 6 year old battery was replaced a month ago, as it died(tested BAD).

The alternator light issue was happening before and after battery replacement as well.

Connections at battery, and alternator are solid.

Further connection checks discovered that at the starter solenoid, were the Positive battery cable is attached, is loose. Not the connection itself, but the whole gizmo to which the wires are attached. It can rotate. I don't believe this should be happening!

I suspect that there may be a bad connections within the solenoid.

Or could it be that when bench tested cold, it was good, but with once run, and thus the alternator gets warmed-up, that the diodes/etc start to fail.

Is the charging system integrated with the starter/solenoid, and possibly causing the issue, and the battery drain?

Your thoughts are appreciated! ?
Avatar
Amoeba
August 26, 2007.




HELLO. Thanks for your reply!

Did the clean as you suggested, and rec'd reading
of 12v engine off, and 12v engine at idle.

Also moved blk wire(grounding lead} to another grd location, same results.

Note that I recharged the battery overnight, started the SHO up, Alternator light flickered at idle, and the longer the engine ran, the more revs it took to get the dash warning light out. Eventually the ABS light kicks in, and shortly thereafter the engine dies. Battery is dead. Recharge, same as above again.

?
?

Tiny
Amoeba
Aug 27, 2007.
HELLO. Many thx for your response! : D

12V was using a analog meter(250V scale lowest available), therefore difficult to attain precise read.

Found my digital, and read as follows: - 12.60V engine off
- 11.96V engine idle(800rpm)
- 12.01V engine rpm's upped to the point were
warning light goes off(3000rpm)
- 12.62V charger on, test on cable clamp ends
- 12.62V charger on, test reading on post
- 16.20V cables off posts, charger on cables only

Battery drains after about 5 - 7 miles, but vehicle has Daytime Running lights, so that'll empty the battery quicker.

Many thanks! : D

Tiny
Amoeba
Aug 27, 2007.
Hello !

Yes, 12.62V reading with charger on and engine off.

I'll get you the other readings tomorrow, as I'm in the Eastern time zone, and it's dark out now.

Thanks again! : ) 8)

Tiny
Amoeba
Aug 27, 2007.
Good Afternoon(EST) : )

Thank for all your input first of all.

You asked for a reading, ". Would also like one at the alt. B+ post and cable. Engine off. This is the yellow/white wire coming from your starter solenoid.&Quot; I'll have to get under the car for that and check for the color coded wire you mention.

Aside from the big + cable connected to the Alternator, I have a plug-in connector which has
3 wires, WHITE, BLACK & GRN & WHT.

NEXT. Post reading, cable off after having charged (trickle charger) battery overnight is: 12.74V

ENGINE did not DIE when I pulled off NEG battery cable, nor did it DIE when I put the NEG back on and pulled off the POS cable.

VOLTAGE test, POS connection(big cable)on alternator and tester negative lead on Neg battery post gave a reading of: 12.74, engine off.

Interesting is that it seems that when the engine is cold, the Alt warning light doesn't sometimes illuminate, but seems to appear more often once the engine components have warmed up.

Today, on 1st start-up, the warning light didn't light up. Shut off engine, restarted, light on @ idle, and off with RPM's over 1000. Upon the engine being run for a minute or 2, a shutdown, then restart have the RPM's at 1200 before light goes out. It seems to progessively get worse the longer/warmer
the engine gets.

In my 1st post I mentioned that the Solenoid housing can be twisted(it's loose). Is that due to design, so that the cables attached to it don't break with engine flex? The starter works fine, but is there any connection within the Solenoid that may be the culprit with my chargin/warming light issue?

Looking forward to your thoughts! : D

Tiny
Amoeba
Aug 28, 2007.
Howdy. 8)

Serpentine is 3 mths old, and as well the SHO
uses a pulley/tensioner to keep the optimum tension on the belt. I've replaced the Serpentine a few times since I've had the vehicle since new, I find that a socket on the end of a pull bar works beautifully. Very little effort required.

RAD. Replaced last summer, and upon checking today, no debris, etc. Spotless! Good thing!

I will pull the starter and check out the Solenoid and respective connections.

I'll keep you posted as to the outcome! : )

Tiny
Amoeba
Aug 28, 2007.
Howdy 8) : )

Pulled the starter & solenoid, and though there was a little movement in the casing, it was not affecting it's operation. It's electromagnetic, thus no wiring internally. Checked other starter connections, all OK.

SERPENTINE BELT. Though it was 3 mths old,
I picked up another one when I picked up the solenoid.

Installed the Serpentine, and all seemed to working well, but I noticed an ever so slight squealing(nearly inaudible), and then noticed the dash warning light come on. AGAIN!

I took it for a drive, light would go out at approx. 1000 RPM, and go on again at idle, and off once RPM above 1000. The more the engine ran, the higher the RPM's had to be taken to get the warning light to go off.

Up with the hood, pull bar and socket onto SERP-
TENSIONER PULLEY nut, pushed it is the opposite direction(towards firewall) of loosening belt, and lo & behold, fixed the problem. For now.

I believe it is the TENSIONER, and a it's internal spring.

I will replace TENSIONER, and let you know the outcome.

8) 8)
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Tiny
Amoeba
Aug 29, 2007.
August 30th/2007

Well, replaced the Serpentine belt, and had the Tensioner tested, and it's good!

Problem is back. Warning light came on at idle again, and then off again, and progressively higher RPM's needed to get light to go out.

Battery drained, engine died. Charged battery up againe, started engine, and at idle pulled NEG battery cable, and this time it stalled the engine.

I am still thinking that once the Alternator heats up, and that's when the light starts coming on, that the unit is defective, though it bench tested GOOD.

What do you think, is that possible? The Charging diodes/regulator starts to fail with heat buildup.

Your thoughts once again would be appreciated.

Thanks 8)

Howdy 8) : )

Pulled the starter & solenoid, and though there was a little movement in the casing, it was not affecting it's operation. It's electromagnetic, thus no wiring internally. Checked other starter connections, all OK.

SERPENTINE BELT. Though it was 3 mths old, I picked up another one(your suggestion to replace) when I picked up the solenoid.

Installed the Serpentine, and all seemed to working well, but I noticed an ever so slight squealing(nearly inaudible), and then noticed the dash warning light come on. AGAIN!

I took it for a drive, light would go out at approx. 1000 RPM, and go again at idle, and off once RPM above 1000.

Up with the hood, pull bar and socket onto SERP-
TENSIONER PULLEY nut, pushed it is the opposite direction(towards firewall) of loosening belt, and lo & behold, fixed the problem. For now.

I believe it is the TENSIONER, and a it's internal spring.

I will replace TENSIONER, and let you know the outcome.

8) 8)[/quote: ceffacc50e]

Tiny
Amoeba
Aug 30, 2007.
HELLO : D : D : D

Last night, after a week of frustration, but with a load of helpful suggestions & knowledge provided by
JUSTANOLD, and after having checked all pulleys that the Serpentine motivates, and finding them spinning freely, I stopped & rehashed how & when the problem showed itself.

OK. READY, I've found the problem, and the issue is fixed! YEAH!

The flashing Alternator light never came on when the vehicle was cold, but as it warmed up, the RPM's, as mentioned in my previous posts, needed to be increased in order for the light to go out. And ultimately, as the engine ran for longer periods, the light wouldn't go out any longer.

SO. When cold it was GOOD, NO GOOD when hot.

Though I had the Alternator bench tested near the beginning of the problem, and it had come back as GOOD, I was still thinking it was an issue with heat.

Last night, I pulled the Alternator out when it was HOT, took it to be bench tested, and lo & behold, it failed the test! Ordered a new unit, and when I picked-up it up today, I had the old unit tested again whilst it was COLD. The old unit tested OK!

SO. It was the Alternator afterall, and a internal heat generated issue. I suspect the regulator diodes, or such to be the culprit!

Many thanks to JUSTANOLD, as his thoughts and recommendations were most appreciated, and very knowledgeable, and if it weren't for his input, I would have not eliminated all the other possibilities that may have caused my FLASHING ALTERNATOR LIGHT problem.

Many thanks. : D : D 8)

Tiny
Amoeba
Aug 31, 2007.
HELLO : D : D : D

Last night, after a week of frustration, but with a load of helpful suggestions & knowledge provided by
JUSTANOLD, and after having checked all pulleys that the Serpentine motivates, and finding them spinning freely, I stopped & rehashed how & when the problem showed itself.

OK. READY, I've found the problem, and the issue is fixed! YEAH!

The flashing Alternator light never came on when the vehicle was cold, but as it warmed up, the RPM's, as mentioned in my previous posts, needed to be increased in order for the light to go out. And ultimately, as the engine ran for longer periods, the light wouldn't go out any longer.

SO. When cold it was GOOD, NO GOOD when hot.

Though I had the Alternator bench tested near the beginning of the problem, and it had come back as GOOD, I was still thinking it was an issue with heat.

Last night, I pulled the Alternator out when it was HOT, took it to be bench tested, and lo & behold, it failed the test! Ordered a new unit, and when I picked-up it up today, I had the old unit tested again whilst it was COLD. The old unit tested OK!

SO. It was the Alternator afterall, and a internal heat generated issue. I suspect the regulator diodes, or such to be the culprit!

Many thanks to JUSTANOLD, as his thoughts and recommendations were most appreciated, and very knowledgeable, and if it weren't for his input, I would have not eliminated all the other possibilities that may have caused my FLASHING ALTERNATOR LIGHT problem.

Many thanks. : D : D 8)[/quote: b77814f0ac]

OK. HELP NEEDED AGAIN!

What could be frying my alternator?

Replaced with new one. It lasted 15 miles.
Bench tested. Fried! NOTE, that when Bench tested with Alternator cold, tested good, but
I reinstalled(having recharged battery to 12.7V),
ran engine for 10 minutes, pulled Alternator, it was hot, Bench tested, FAILED!

YES, it could be new unit was defective, BUT, could there be anything else frying the Altermator?

Ground, starter, etc, connections all good.

Battery good(new).

Serpentine NOT slipping. Tensioner is Good.

Pulleys all spin freely.

Symtoms. Flashing Alternator light, progressing takes higher RPM to get it to go out, eventually doesn't go out with higher RPM's, battery drains, engine dies. Recharge battery, runs great, but does same thing all over again.

Do not wish to install new alternator, and have it fry as well!

Any thoughts/help would be appreciated.

Tiny
Amoeba
Sep 4, 2007.
HELLO.

LOL! It was a nice warm feeling for a while! : Lol: My Trickle charger is a 6AMP unit, but I borrowed
my neighbours, and his is a shop quality charger.

Yes, the battery(new a few mths ago)is fully charged at 12.7V.

I believe I mentioned it in my post, but COLD, the Alternator tests GOOD, reinstalled, ran engine(with fully charged battery), pulled Alternator with heat in it, had retested(Bench), FAILED.

Have picked-up new Alternator(warranty)this afternoon, and will install, and let you know!

Many thanks for your feedback.

: )

Tiny
Amoeba
Sep 4, 2007.

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