Battery Light Came On...Fixed For Cheap!
 

My '02 S with 19k miles had an issue recently. I'd just removed the car from winter storage, where it was on a maintainer all winter. Had to take the car for emissions testing, so picked a nice 70 degree spring day and went out for a drive to the station, which was about 20 miles away. Car performed flawlessly, but the battery light came on shortly after I left the station and remained on for the entire 20 mile drive home.

Upon testing with my DMM, the output was only 11.8 volts at the battery terminals whether the car was running or not...obviously an alternator issue. After researching here and a couple other sites, it appeared to be a common problem and likely a bad voltage regulator. There is no Porsche part I could find, but Audi, VW and MB use the same component, so I ordered a replacement Bosch F 00M 145 350 unit (made for a German company in Mexico, for a car built in Finland).

Long story short, following 101 Projects for Boxster book, I removed the alternator (royal PITA) and installed the replacement regulator. Fired it up and voltage at the terminals back to 13.8 to 14.3...success!

This part only cost me $54 and is readily available. Before shelling out for a new or rebuilt alternator, you may want to check into this remedy, as it saved me a few bucks.

Some VW, Audi, Mercedes, and even some Ford models use the exact same voltage regulator; but for some reason Porsche only wants to sell you a complete alternator……..

"why make $60 when we can make $400" i believe is the reason.

I'm glad there are people out there smarter than I when it comes to these issues...I've learned a lot from these forums. I tried to cross-reference the part at Pelican, but it still didn't come up, so I ordered from a VW website. My engine got a nice detailing since it was so accessible...

Voltage Regulator Replacement
 

Wanted to say thanks for the tip on the availability of the Voltage Regulator. :cheers: Saved me a bundle on my 01 Boxster. The VW dealership had a little trouble cross-referencing the Bosch number so here is the VW number for anyone who needs it. VO38-903-803-EX. Cost me $98 in Toronto. Also regarding the removal of the alternator which can be tedious, make sure you free up the bushing at the back of the upper bolt. You will have to get to it with wd40 and wait. It needs to be backed off to give the required clearance to rotate the alternator to clear the bottom mounting. If you do that, the re and re is quite easy.

Alan

How is that your firewall is soooo shinny???

Thanks for the tip!

My alternator is acting up. The light comes on and off. I changed the old-looking serpentine belt but that didn't change anything. Now to tinker with the alternator.

Just attempted this repair on my Boxster. Bought a regulator off of Amazon. It arrived and it was a Chinese knock off. I installed it anyway against my better judgement. I started the car, the battery light went off and it was fine. Checked the voltage and it was putting out around 14.4 volts, for almost exactly 1 minute. Then the battery light went back on. All of the sudden it was putting out 18 volts and climbing. I cut it off, and called the carquest distribution center about 25 miles away. They had one in stock (they also have a store attached to the warehouse). They set one aside for me and I went and got it. On the way there I stopped at Pep Boys and had them test it just to verify that it was the alternator and not something else. It was the alternator and it tested at 18 volts for them too. Got the reman unit from carquest. $160 and a lifetime warranty. Put it in, and started the car. 13.8 volts and it stayed that way. Drove it around the block a little, warmed it up, and let it run for about 30 mins. Had the AC running so that it had a load on it. Ran great. At also idles more consistently now, and the lights don't flicker (the regulator was failing for months).

One quick tip. The bushing seems to be what every one struggles with. I used and air chisel and had it driven back in seconds. Put a 15mm socket with a 1/2 drive on the bolt, ran a 12" 3/8 extension through it, and put the chisel bit on the end of the whole thing. Drove it right back. The whole install took around 5 mins. Putting the interior back together was the hard part.

Be careful with the part numbers !
The Bosch # in the OP post may have been superseded according to an old post in Renntech ? F 00M 145 225 or 350 ?

See more here and DIY + photos:
Alternator repair - Regulator replacement - Pelican Parts Technical BBS
Here is the Renntech link:
http://www.renntech.org/forums/topic/36753-where-to-buy-voltage-regulator/?_fromLogin=1
YEMV