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Discussion Starter #1
Originally posted here: http://www.focusfanatics.com/forum/showpost.php?p=6887265&postcount=13


Originally Posted by InfraredZTW View Post
Car runs great now.
The only thing i noticed is:
- upon a COLD START only - all lights will go from dim to bright about 3 times, then the smart charge kicks in (as shown by the handy batt/alternator tester plugged in the cig. lighter) and slowly comes up to perfect alternator voltage output
- on HOT START - car starts perfectly with no light flicker
- after engine heats up, if i turn accessories on (ac, defrost, etc) the alt voltage drops and stays down at idle.
My car is having pretty much the same issues. More info:

- Problem was first noticed about a week ago.

- On a cold start (cold is not cold outside - maybe 60-65 ambient Fahrenheit), when first driving (night, headlights, HVAC Defrost, Rear Window Defrost On), lights will alternately dim down heavily. Most noticeable with the instrument cluster lights, but you can tell the headlights and HVAC lights are dimming also.

- This is not a mild dimming issue - cluster goes from bright to almost unreadable, lights are obviously much dimmer than normal. (I don't keep the dash lights super-bright, but I would estimate the lights with the dimming are not as bright as they would be with the engine off and only the battery powering them.)

- There doesn't seem to be a pattern to the dimming. Lights DO NOT vary with RPM. I've seen the lights go dim as the RPM is increasing and vice versa. No real time pattern either - sometimes they will dim for 2-5 seconds and then be normal before repeating, sometimes for only a 1/2-second or so.

- Once the engine reaches normal operating temperature (190-200 degrees) (3-5 miles of driving), the problem goes away and won't happen again until the next morning (that I know of - I don't usually drive at night.)

Troubleshooting info:

- Car is a 2002 Ford Focus SE Comfort ZETEC Automatic Sedan with 143K miles. (It's blue.)

- Alternator was replaced 4-months ago. Autozone alternator replacing defective older Autozone alternator.

- Battery is Autozone 40R-72, 30 months old, 24-months free replacement, 72-months pro-rate.

- Yesterday evening, I checked battery terminals: tight, cleaned off minor corrosion; and fluid level (at bottom of split ring but above plates, added a slight bit of water to bring level to top of split rings), battery surface voltage was 12.71 to 12.35 - but this was warm temp after driving the car home. No real change in the morning - duration of dimming might be slightly less, but still occurred. Did not check alternator connections.

- During the day with a DMM - readings are normal (i.e. 12.65 surface volts, 12.3 volts after lights on for 30 seconds without engine running, 14.1 volts with engine running and lights and defrost on).

- About a month ago, I replaced the dome, trunk, HMSL, and license plate bulbs with LEDs. Likely unrelated, but that is the most recent semi-major change to the car.

- I added heavier ground wires years ago between the engine and the fender and the battery negative and the fender.

Theories:

- The battery could be going out, it's about time (just after the free replacement period), but the post above said a new battery made the issue worse, so ...

- I suppose something could be drawing the battery down overnight so that it still had enough juice to start the car, but was loading down the alternator - but I would expect the dimming to vary with RPM, then.

- Possibly something with the new alternator - It is lifetime parts warranty and I think still within the labor warranty (a shop changed it, it died away from home four months ago).

- Possible voltage regulator (which means new alternator).

- Possibly bad ground points, but I'm not sure how to check these.

- Possible wiring connection issues - I've read of Focus's having problems with the alternator connector plugs, but I'm not sure what I should be looking for.

Questions:

I am considering having AutoZone run a free "cart test" on the alternator, but not sure this would find the issue if it is wiring and since it is intermittent and only with the engine cold.

I don't have an easy way to test the voltage output while driving - I have an Ultraguage, but it is the older model and doesn't read battery voltage on the Focus - http://www.amazon.com/INNOVA-3721-Battery-Charging-Monitor/dp/B000EVWDU0/ref=cm_cr_pr_sims_t would work - but I hate spending $14 to find out the voltage is dropping in the morning, which I can already tell.

Thanks in advance for suggestions!!!
 

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THe main battery ground is by the airbox. Remove it sand down the fender-well contact point to bare metal, do the same to the connector on the ground wire, wire brush the bolt too. Re-attach and cover with dielectric grease.

Post results.
 

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For voltage checking, you can use the test function of the odometer. Just hold the reset button while starting, and after started you can page through functions with repeated presses to find voltage.

Old school method would be hooking up a voltmeter, plugging a spare aux. power connector into the port is the easiest way.
 

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Discussion Starter #4
For voltage checking, you can use the test function of the odometer.
I forgot about that, but the problem is that the regular odometer doesn't work while you are in that mode. It's not bad for a quick check, but not something I would want to do daily until the problem is resolved.

I'll try the grounding and grease suggestions and report back.
 

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Discussion Starter #5
It didn't FIX the problem, not sure if it helped or not. The number of times the lights dimmed and the duration of each time MIGHT have been less, but it could have just been a co-incidence as well.

BTW - I did five ground points, the main one by the airbox, the small wire to the outside of that, the small wire in front of the passenger motor mount bracket, the ground on the passenger shock tower, and the ground on the engine lift ring bracket.
 

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this likely isn't wiring since the problem goes away when the car is warm.

In my guesstopinion it is the voltage regulator. The issue is when the car is cold it has to be recharging the battery since you just sucked a lot of power out of the battery when starting the car.

You need to get an assistant to cold start the car while you have a voltmeter on the battery terminals. As soon as the car is started and running voltage on the battery terminals should go to 13.8-14v and stay locked there. My guess is that during the dimming the voltage is jumping all over the place. By the way the kind of voltmeter that uses a needle is easier to see this kind of thing with.
 

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Discussion Starter #7
Most of the other threads were saying VR also - which I understand is internal to the alternator ...

Some more questions:

  • Could it instead be a problem with the main power wire on the alternator and/or the pigtail connection and is there an easy way to check for this? (It seems like the same logic somewhat applies - if there is a weak connection there, the dimming occurs at cold start b/c the battery was discharged, but there is enough of a connection to maintain the battery after the engine warms up.)
  • Would a faulty VR be diagnosed on the little roll-out cart test at AutoZone even after the engine had warmed up?
  • I suppose I would have to check with the shop, but the alternator (and VR) is lifetime warranty from AutoZone, and I think the install had a 12-month warranty. Is it unreasonable to expect the shop to install the replacement alternator for free - even though I basically supplied them the replacement alternator and it wasn't their install that likely caused it to fail?
  • Any really better options for repair/replacement? It's free at A/Z and the car is old enough that I don't want to put a lot of money into it, but the alternator is enough of a pain to swap out that even if they are free, swapping one every five months is not a good deal.
  • What is the downside to doing nothing - i.e. if everything works fine after the car warms up - is it an option to just live with the lights dimming for the first five minutes of the drive, or am I likely to fry the ECU or PCM or something expensive if I just ignore the problem?
 

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sounds like a weak battery to me. I'd buy one and run it for a couple days, and by process of elimination rule that out. if it doesn't fix it take the battery back.
 

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Discussion Starter #9
The AutoZone roll-out test will check the battery as well, I guess.

The issues I'm having with that:

The thread that I originally posted to, InfraredZTW was having the same issues and he said a new battery didn't do anything for the issue (but he might have the same symptoms and a different problem.)

The battery is 30 months old, and I'm getting tired of AutoZone batteries as well. They seem to never last longer than 3 years and also never fail until after the free replacement period. Ideally, I would like to get the pro-rated portion of the battery credit back and go back to a Motorcraft battery, but the parts store doesn't like to do that.

I'm not sure most store will let you take the battery back after you install it.

(And I don't want to put a battery in the car, find out that wasn't it, put an alternator in the car, find out that wasn't it, and then end up doing a simple wiring fix that would have solved it for $10 to begin with ...)
 

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TM's suggestion on testing is a good one, need to confirm just what is happening when & where.

You're on the right track on the installation warranty, no problem with the install means they shouldn't be doing it again for free.

When a shop sources parts, then the whole job is warrantied. They make a profit on the parts alone, but some of that goes towards handling parts warranty issues & repeat work in the case of a parts failure. Parts picked by a shop are usually more expensive even before their cut, the choice is based on good experience with reliability & service when there is a problem. Parts that fail, even if warrantied, are a loosing proposition for a shop.
 

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Discussion Starter #11
Okay - I got some rough numbers.

(Don't try this at home, but I managed to turn on the map light, hold the DMM probes in the cig lighter with my right hand, and drive with my left hand.)

Numbers are from memory though.

Initially, voltage was around 12.3 (engine off, map light on) - a bit low, but not awful.

Started the engine, turned on headlights - voltage dropped to around 10.5 (???) and quickly came back up to around 14.2 (maybe 10-15 seconds).

Driving - voltage randomly dropped and rose - lowest was probably 11.3 and highest around 15.8. This gradually damped down and settled to around 14.3-14.5.

So - the dimming is obvious b/c the voltage is dropping well below resting battery voltage and rising well above normal alternator output. And the voltage is somewhat like a dampening sine wave - high initial amplitude, then dissipating.

So the remaining questions are:

  • This is seeming more like a voltage regulator issue - but I'm not sure why it only works improperly in the first 3-5 miles of driving and then seems to work fine.
  • Not sure if it could be a weak battery - seems odd that the voltage is normal right after starting the car, then drops down after I start driving.
  • Not sure how bad leaving this alone would be, but with voltage occasionally approaching 16V, it's probably not helping anything.
 

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It seems like a VR issue but it's not, actually. You have a wiring issue. Bad grounds or whatnot.

Look at it this way. The battery is a giant pool of electricity. It is at 12 volts normally. When things are running the electrical system raises the voltage to 13.8 and that causes electricity to flow into the battery much like if I stood next to a swimming pool and turned on a hose, trying to raise (charge up) the water of the pool.

But, the electrical system cannot make the battery voltage go below 12 volts because if it does the battery starts flowing power into whatever in the electrical system is sucking power. And the battery can flow a LOT of power FAR MORE than me and my garden hose. It would be like I dug a hole next to the swimming pool then tried digging into the pool to get the water level to go down, the moment I broke through the pool would flood me to it's level in an instant.

The fact your seeing low voltage below 12 volts while driving means there's a high resistance connection from the battery to the rest of the system - specifically from the battery to the alternator. It could be broken wires in the alternator plug, or a bad connection in the harness or bad grounds or whatnot. Or it's a poor or corroded or burned connection. That resistance is preventing the battery from forcing the system's power level to at least 12 volts. And that resistance makes the voltage regulator wildly swing the field current in the alternator around which makes the alternator output go crazy. the resistance is essentially making the voltage regulator "see" a lower voltage than what is actually there, so the regulator jacks up the alternator output quite high.

Eventually an equilibrium is reached and the system settles down. Either that or the vibration makes the poor connection rattle a bit and shine up some metal a bit so that power flows better.

Unfortunately this kind of thing is a bitch to troubleshoot. You need an electrical diagram, and you need to trace each wire in between the battery, and the alternator, and the grounds, and the harness connectors. Usually in these systems, the part of the harness in the engine compartment starts to disintegrate first, due to the heat and vibration underhood. Someone with experience knows where all the weak spots are and they will go check them first. if it was me I would look very carefully at
the wiring behind the alternator. Any very sharp bends in the wire should be suspect. Wires are not support devices but when hoses and such break free underhood and lay on them, then the wires take the stress for a while then start breaking a strand at a time inside the insulation. You can have a wire that looks perfect but the conductor has fractured inside and the 2 ends are grinding together so it won't come up on a casual voltmeter check.

Get the electrical diagram and some modern books on automotive electrical theory and read the sections on how the alternator and battery and regulator all work together until you understand what is supposed to be going on. Then start testing with the voltmeter under the hood at the alternator terminals, battery terminals, and other test points in the system, then think about what happens here when voltage there drops.
 

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^^^^ Hmmm - Battery to harness/power distribution for a first check?
 

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Discussion Starter #14
Hmmmn - okay ...

I got some other info before I read the above.

  • The battery has an $82 credit on it if if is bad (portion of warranty remaining)
  • AutoZone has a new alternator (not rebuilt) for $30 more than my existing alternator - which is under warranty
  • I stopped by AZ yesterday - they said the battery was bad, but the alternator was fine - but the car was hot, so the system was working normally, so I suspected an alternator issue.
  • I stopped by the Ford dealer (planned to get a new battery), but they had closed for the evening. One of the Service Advisors said it was unlikely to be the battery, but they could check it - but it seemed like an alternator, bad ground, or wiring fault and not a battery issue. The basic check was free, but diagnosis was around $100.

Questions:

Where do I go from here? - obviously I want to check connections for tightness at the main alternator connection, but beyond that.

Looking on FordParts - the positive battery cable looks like it lists for $92 and includes the alternator wire. The alternator pigtail lists for $50 but I'm not sure how to reliably splice it or how to know which one I need.

I'm okay with just spending $92 on a new harness and putting that in, but don't want to find out that wasn't the problem - I also might just take it to a mechanic if that ends up being the best solution.
 

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Where do I go from here? - obviously I want to check connections for tightness at the main alternator connection, but beyond that.

Looking on FordParts - the positive battery cable looks like it lists for $92 and includes the alternator wire. The alternator pigtail lists for $50 but I'm not sure how to reliably splice it or how to know which one I need.

I'm okay with just spending $92 on a new harness and putting that in, but don't want to find out that wasn't the problem - I also might just take it to a mechanic if that ends up being the best solution.
Wow, $50 for an alternator pigtail!!!!!! Check Summit Racing for P/N PCO-5716PT (I think that is the correct pigtail anyway).

As for new cables, if you are considering having a mechanic do it, then perhaps an audio installation place might be something to consider. They could make you custom upgraded cables and also install the pigtail for you. Anyone else care to weigh in on this? Better ideas????
 

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Get the battery load tested again for a second opinion, since it hasn't been replaced yet.

If it fails, you can be sure nothing will work right until it's replaced so start with that.
 

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Discussion Starter #18
The saga ends ...

Pretty sure it was the battery - even though the Ford Service Advisor thought that was unlikely (as did I since the car started right up) - but it was a free test at Ford, so I figured it couldn't hurt to confirm what AutoZone showed me.

  • I got a new battery installed from the Ford dealer.
  • After I got home, I disconnected the power wire at the alternator sanded the terminal down, slapped some (dielectric) grease on it, took a fairly sharp bend out of it, and put it back on. Also took off the pigtail, slapped some grease on it, and plugged it back in.

The lights worked fine this morning - it could have been the battery or the contacts at the alternator, but I'm guessing most likely it's the battery.

Anyway - glad to have my car working properly again and that it was relatively simple to fix!!!

Not completely happy with how things were handled at the Ford dealer, though ...

http://machenry.com/documents/batteryspecs.pdf

  • I was sent to the quick-lane, which was fine.
  • He ran the tests and said the battery was weak and the alternator was marginal at 12.9 V. Although I suspected a possible alternator problem, I mentioned that the alternator was an AutoZone, but was only 5 months old. He ran that test again and said the alternator was doing fine under load (which means he didn't run the headlights the first time and the alternator wasn't charging b/c it didn't need to be charging).
  • No mention was made of price - I knew from asking the day before that the 3-year free replacement battery was $120 (same as everywhere else - I was fine with that). The two-year free replacement was $100 ($10 less than most other places) but they try not to sell that - which is okay, but …
  • Not sure why, but the service advisor, the quick lane manager and another desk person at quick lane said the batteries had a 3-year free replacement, 5-year pro-rated warranty. The specs on the side of the battery show 100 month pro-rated warranty, as does the documentation. It's not a huge deal, as I've typically haven't gotten 3-years out of AutoZone batteries and 5-6 years is about right for OEM batterys, but it is the difference between getting 40% credit toward a new battery and no credit if the battery dies after 5-years.
  • Somewhat on me, but I said I needed the old battery back and he said they need to keep it - then he said there was a core charge on it - which he thought was $10 (it was $18). I said I'd pay that as the old battery was worth $82 at AutoZone.
  • He brought out a BXT-96R battery. My battery was a 40R series. I asked about that since FordParts showed both working for my car and he said the VIN showed a 96R was supposed to go in my car. I pointed out that the 40R had more CCA. He started to say the 96R was what was supposed to go in the car and would be fine, then said he'd have to see if he had a 40R if that was what I wanted. I said it was, and he found one. The point is that is never hurts to have a higher-CCA battery - especially if they are the same price - the only drawback is he has to find another sucker to buy the 96R battery. (Other than maybe weight - but this isn't a track car.)
  • This is more on me than them - but I have a 9V battery adapter that plugs into the cig lighter. The JVC radio takes about 20 minutes to program all the settings into it. I said I wanted to plug that in - which was no problem, but apparently at some point he had disconnected the battery already b/c it didn't save my settings and it had when I used it in the past. No big deal - but a minor annoyance.
  • Anyway - in the end I got a new Motorcraft battery for $60 ($120 plus $18 core - $82 Credit from AutoZone) and the car is running fine, so I am happy.

(And it might not have started today or tomorrow with the old battery as the first semi-cold snap of the season is coming.)
 

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Now that everything is working, do the test with the odometer that shows battery and charging system voltage. And measure with a voltmeter at the battery terminals after starting, and write everything down.

The 2 different batteries are specd for that car because on some of them Ford put this insulating "blanket" thing and the battery tray is smaller - those take the 96R batteries while on other cars the blanket is missing and the battery tray is larger - those take the 40R. The blanket thing is useful if your in northern states or Canada, otherwise it will shorten the life of the battery (since it keeps it hotter) The hold down bracketry is different also. There seems to be no rhyme or reason for using one setup over the other in models.

Cleaning up the terminals probably helped as much as the new battery. If the old battery wasn't being properly charged (over or under) that would have shortened it's life.

Most car batteries in the US are made by Johnson Controls, (your Autozone battery and Motorcraft battery were both made by them) Exide, Delco, and GNB.
 

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Discussion Starter #20
What I'm thinking (and one good question the dealer asked) is that when the alternator died five months ago, I didn't change the battery.

The alternator just plain died on the car - no warning lights - driving along and the speedo and temp gauges go to zero. Pulled over to turn the car off and re-start it and see if they will reset themselves and the car won't start. Walk to a shop and get a mechanic to jump start the car and the car dies as soon as he removes the cables.

I'm guessing the older alternator was probably acting flakey and that shortened the battery's life (although 6 months after free replacement seems about right for an AutoZone battery to die).

It just confused me b/c I was used to "Lights dim at low RPM = Alternator", "Hard to start or won't start = Battery". "Lights dim after starting and driving regardless of RPM, then work fine = weak battery" was new to me.

Not sure what battery the car should have had, but the 40R is more CCA, so that's what I wanted. I think the car had one of those blankets initially, but it hasn't had one since it got it's first replacement battery. OTOH- even the 40 has a lot of space (fore-aft) in the tray and isn't really locked in place by the hold-down. (So it seems like I got the larger tray and the blanket thing - ...)

Thank you again for helping sort this out for me!!!
 
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