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David Gieswein
David Gieswein,
Category: Ford
Satisfied Customers: 89
Experience:  Automotive technician at Doug Gray Dodge/Chrysler/Jeep
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Persistent electrical problems, 2002 Ford Focus SE, Engine

Customer Question

Persistent electrical problems
JA: What is the make/model/year of your car?
Customer: 2002 Ford Focus SE, Engine 2.0L SOHC (Not Ztec) VIN:1fafp34p32w171314
JA: How many miles are on the car? Is it an automatic or a manual transmission?
Customer: 95k ish automatic
JA: Are you fixing your Focus yourself? What have you tried so far?
Customer: Yes, give me a minute to detail it fully
JA: Anything else you want the mechanic to know before I connect you?
Customer: Would not start, Junped it and took to Oriley Auto parts, where battery checked good, and alternater bad.
Replaced with Ultima Alternator P/N 8231B, afterwards battery voltage ranged from about 12.4V (not charging) to 17.2V (way overcharging). The Orileys (on the car) tester said the voltage regulator (in new alternator) was bad. Ordered another new identical alternator, but this time had Orileys bench test it before installing it, it tested good. The second replacement alternator did exactly the same things, 12.4V - 17.2V and (on the car) testor showed bad regulator. The original replacement alternator was also bench tested and found to be good (on the bench tester only).So I have two replacement alternators that test good on a bench tester in the auto parts store, but test bad in the car with very erratic voltage. All connections are clean and tight.Since then I have replaced: the battery, PCM and alternator pigtail. Additionally the instrument cluster is acting up, it goes from 0-140 mph and all other gauges make a similar swing, and the battery light goes on and off at random.
Submitted: 6 months ago.
Category: Ford
Expert:  Chris (aka- Moose) replied 6 months ago.

Welcome, I'm Chris (aka Moose) I prefer to work when others don't, I am here around lunch and after dinner till after midnight.

On the instrument cluster, I would hold off on it till you get the charging voltage right since electronics can mess up when not in the correct voltage range. This is a PCM controlled charging system and this is a finicky system when using cheap aftermarket parts. It could be the less quality alternator not operating correct based on the commands from the PCM causing this. I would like you to do the Ford charging system tests but the results are based on a motorcraft alternator so the results may be incorrect with this aftermarket part on the car. Can you do the tests below.

This is my 1st answer, but does not have to be my only answer. You the website and myself expect you to have a ~~~5 STAR EXCELLENT~~~ experience with my help. Please let me know if you are pleased by selecting a star rating above or by replying and saying your pleased. Not rating or rating 1-2 stars does not benefit you nor me in any way. Follow up and reply as often and when needed, there is no extra charge to do so.

Thanks Moose.

Customer: replied 6 months ago.
I had already performed all of those pinpoint tests BEFORE I replaced the PCM. The greatest voltage drop on any of the legs of the circuits was 30mv. To reiterate, and give a little more detail, I have replaced 2 alternators, both tested good on a bench tester (at O'Riley's) but both tested bad on my car (O'Riley's on car tester shows both have bad voltage regulators). This prompted me to check continuity between the alternator pigtail pins and their two locations in the PCM connector, and the fuse block (under hood). I had continuity between the connecting ends of these three wires (I can get you the pin numbers if you want). I also verified that the two wires between the pigtail and PCM were not grounded or contacting each other. After this test I replaced the pigtail anyway, because it was cheaper than the battery or PCM (connections were soldered and covered in shrink tubing). Then I replaced the battery. Then I replaced the PCM. The erratic voltage and intermittent battery light problem still persists, and the O’Riley’s on car tester still shows a bad regulator, but only intermittently (one time it will test good, and another time it will test bad). I should also mention that NONE of these problems (including the instrument cluster problems) happened before I replaced the alternator. I have also been in EXTENSIVE contact with technical support at the alternator rebuilder (BBB Industries), who says that the aftermarket regulators did have problems in the early years, but those problems had been solved over a decade ago.
Expert:  Chris (aka- Moose) replied 6 months ago.

Thanks but I do not need the pin numbers, I have the Ford diagrams with my Ford tech login.

Based on all these test results I recommend a motorcraft alternator be installed to resolve this charging system concern. Which is also the Ford recommendation on the last pinpoint test.

Customer: replied 6 months ago.
Additionally, there are NO trouble codes, and I have checked with 2 different code reading devices, an Android phone running the Torque app and A low end code reader.
Customer: replied 6 months ago.
This is exactly what I was afraid of. This is not an acceptable answer. Tell me what I can test to see what is not working.
Expert:  Chris (aka- Moose) replied 6 months ago.

I do not understand how it is not an acceptable answer. You said you did all the pinpoint tests and they passed and in step A8 it says check for codes. You said there are no codes. Ford then says to replace the generator/alternator. You have addressed the possibility of it being a PCM and the wiring. The only thing left is the alternator.

There is nothing left to test. Know its time to replace the alternator with the correct one designed for your car.

Customer: replied 6 months ago.
It may be helpful to not that there are two documents published on this subject, by the Electrical Rebuilder's Association. They are "Ford 6G RegulatorsPCM-Controlled and Non-PCM-Controlled" and "Ford 6G Update:Troubleshooting Warning Lamp Problems" however, I do not have access to them because you need to be a member of the rebuilder's association. Here's a link in case this helps. This at least shows that this is a common problem. scroll down to see these two documents.
Expert:  Chris (aka- Moose) replied 6 months ago.

I do not have access to that website either since its not associated with Ford.

What other part do you feel like could be to blame since you say it is not your aftermarket alternator, assuming all the tests were done correct?

Do you need a wire diagram?

I am pretty much out of stuff to offer to help you since you say the way Ford diagnosis this concern is wrong.

Customer: replied 6 months ago.
I have wiring diagrams, but thank you. The 6G charging system has a 3 wire pigtail, one of these communicates alternator output to the PCM, one sends a square wave signal from the PCM to control the regulator, the third wire is a battery reference voltage. Are you familiar with this system and its workings?
Expert:  Chris (aka- Moose) replied 6 months ago.

Yes I know how this charging system works.

Customer: replied 6 months ago.
Ok, so what is required to test the communication between the PCM and regulator?
Expert:  Chris (aka- Moose) replied 6 months ago.

You would do an ohm test on the 2 wires with the alternator and PCM unplugged. Verify the wires are not broken and then verify they are not shorted to power and ground, which you said you already did.

Next you would need an oscilloscope to monitor the signal from the PCM to the alternators regulator.

Customer: replied 6 months ago.
Ok, so if I go borrow an oscilloscope can you advise me on how to proceed? In detail? Have you done this type of troubleshooting before?
Expert:  Chris (aka- Moose) replied 6 months ago.

Yes I have used an oscilloscope about once every 2 weeks. I am only familiar with the Ford tool that works with the IDS scan tool tool VCM link but I will try.

Customer: replied 6 months ago.
It appears that you do not intend to answer further. I understand that you may not have the information I need. So how do we end this amicably, with me not giving you a bad review and me getting a refund?
Expert:  Chris (aka- Moose) replied 6 months ago.

I will opt out so another can help since you do not believe me that the alternator needs to be replaced.

I will be removed from this post now and another will help from here on. Best of Luck.

Expert:  David Gieswein replied 6 months ago.

Hello my name is ***** ***** I can help you. I have been looking over your comments and everything you have done. It looks like you have hell with this thing. I would like you to do some simple testing I believe can possible shed light on issue. You can respond now or in the morning, I know it is late.

Expert:  David Gieswein replied 6 months ago.

Do you still need help with this issue, I believe I may have an answer?