A-3 voltage regulator replacement

I replaced the voltage regulator this morning. Here are a few of my observations...recommendations:

First off...the alternator does not need to be removed from the engine compartment...it just needs to be unbolted from its mount bracket.
Also...have the radio security code on-hand.
1. Remove the whole air filter box (makes a world of differance gaining access).
2. Remove the serpentine belt tensioner roller (access to remove the lower alternator mount bolt).
3. Disconnect the batterty (the power line from the battery to the alternator is NOT fuse protected).
4. Remove both alternator mount bolts (you'll have to use a tool to get the serpentine belt tensioner arm out of the way..to faciliate the removal of the lower alternator bolt).
5. Disconnect both electrical leads on the rear of the altenrator.
6. Remove three (3) screws and then remove the rear alternator access cover.
7. Remove the two (2) voltage regulator screws...slip the voltage regulator out of the alternator.
8. Install the new voltage regualtor...and put it all back togeather.

Total time....about an hour

I am a dummy trying to figure out what might be wrong with my 97 Passat TDI. What are the effects of a bad voltage regulator? Could this cause the car to simply shut off?: especially during cold starts? Would appreciate the knowledge either way.

I will note that I just replaced an A3 (Jetta 1999.5 120A) voltage regulator without unbolting the alternator or removing anything else. It's a little tricky working in there without much room but it is possible. If you only have a good flex or U-joint for your tools, unbolting the alternator may be easier.

-K

kanoa said:

A3 (Jetta 1999.5 120A)

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1999.5 Jetta is an A4.

Simon

May I assume the B4 task would be similar to the A3 outlined above?

rdkern said:

May I assume the B4 task would be similar to the A3 outlined above?

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I dunno. New one just came in for the 97 B4. Lets go to the garage and see!

rdkern said:

May I assume the B4 task would be similar to the A3 outlined above?

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The answer is yes.

Only thing I did different is leave the serp tensioner roller in place. Remove the two 6mm allen head bolts that hold the tensioner spring. Arm will swing out of the way so you can get the lower alternator bolt out. Spend a couple of minutes with a deep socket and mounting bolt to slide the lugs back a bit for easier reinstall.

14.5 volts, baby! Old voltage regulator was putting out 18+ volts. Brushes were only about 1/8 inch long.

Just for reference. Bosch 120 amp voltage regulator, part #1197311530, $49.38 from autohausaz.com.

Thank you. I've been getting a "voltage issue" and "gp issue" codes for a bit. The cel isn't on now, and I've been too lazy to fix the gp, but the battery doesn't seem to be charging like it should. I'll test, then, most likely, send for the part.

Worldimpex didn't see the regulator as an option. Thank you for the part number.

About to swap out the voltage regulator on my B4. A pre-emptive strike because the brushes must be near the wear limits. Here's the question, does the "alternator access cover", the black plastic thing serve any purpose other than pissing people off? Seems the VR could be changed without taking the alternator out if that cover was not there.

RabbitGTI said:

About to swap out the voltage regulator on my B4. A pre-emptive strike because the brushes must be near the wear limits. Here's the question, does the "alternator access cover", the black plastic thing serve any purpose other than pissing people off? Seems the VR could be changed without taking the alternator out if that cover was not there.

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Correct. But it keeps dirt and some moisture out of the alternator. It also keeps things from touching the alternator internals and causing short circuits.

It only takes about an hour to change the VR normally, so no biggie.

paramedick said:

Correct. But it keeps dirt and some moisture out of the alternator. It also keeps things from touching the alternator internals and causing short circuits.

It only takes about an hour to change the VR normally, so no biggie.

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Thanks, the old-school cars were uncovered except for a thick rubber boot on the hot lead. Took about 60 seconds to change a voltage regulator. I guess more protection against an accidental short is a good idea.

The brushes from my 97 at about 270,000 miles. Guess I got my money's worth out of those eh?

BKmetz said:

The brushes from my 97 at about 270,000 miles. Guess I got my money's worth out of those eh?

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Wow, amazing they lasted that long. On an A2 I went through at least three sets by that mileage. Usually when they are that short she barely charges 12.5 volts.

Thought I would post this in case someone is stuck and needs to get their alternator charging PDQ. My charge light came on and would go dim, bright, and off on the way to work. When I got home, I removed the regulator to find it looking like the picture above. Since I drive 2 hours per day and I couldn't get the needed part for a day or 2, I decided to do a quick fix until my new regulator came in. I took a 5/32" drill and drilled out both holes in the brush/regulator assembly. This allowed me some room so I could position the brushes closer to the armature. I held the assembly tight to the armature direction while I tightend the 2 screws. By moving the brushes closer, the alternator began functioning normally and bought me the extra time I needed to get the part. You never know when you might have use of this trick, but I can attest that I have driven 4 hours like this without issue - may get you home some day.

Nice! Any special drill bit for drilling the ceramic? Maybe a pic to clarify which holes.

Tony

TonyJetta said:

Nice! Any special drill bit for drilling the ceramic? Maybe a pic to clarify which holes.

Tony

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The 2 holes you see in the picture directly above my post. Not ceramic - its plastic. The only trick is the one hole has a rivet, which I carefully held in a vice while I drilled so it wouldn't spin.

Where is the best place to get one of these? I need to replace mine. Somehow the local parts shop (Autozone) is cheaper at 75 bucks than 1stvw and impex. Maybe I am looking up the wrong part. Mine is a 97B4

Look at autohausaz.com They list it for $52

Tony

Thanks! I forgot all about that place. Ordered a few other things I needed while I was there

You bet!

FYI...I keep a list of my favorite TDI parts suppliers to A) Paste in, to help others and B) To remind me of where to look.

Tony

starrd: Great tip, I just made use of this today. I found it was enough to just drill out one of the two holes. Definitely an interim fix, but it let me prove that the brushes were the only problem.
I hate the idea of forking out $50+ to replace a regulator just to replace 50 cents worth of brushes, so now I'm gonna try and find some replacement brushes. Anyone know where I might find some?

Do a search on the tdi club. IIRC, there was a post, by Hemtdi, I think, that posted a company that sells alternator parts.

Tony

Voltage regulator repaired

Thank you all for your contribution, it gave me the courage to attempt my half repair of the V.regulator on my 04 TDI Jetta.

It all started with battery light coming on and some clunking in the tranny followed by engine light and a p2637 code, I assumed this was an incorrect and misleading, this after I metered the voltage and saw no sign of charging. wasn't looking forward to removing the alternator and decided to go for the regulator, it took me an hour to pull it the first time, 5 minutes to put it back, while I had it out decided to take a peek into the electronics, I found a transistor and a capacitor floating in the cooling gell, cleaned the gell and resoldered the 2 components (surface mount) back, now it is charging except I do not get the battery to come on at all, troubleshot, the bulb is ok, I guess I better get the regulator replaced, but at least now I know it is the trouble and the car is driveable.

where is the best place to shop for VW parts in the Toronto area, I am new to VW and TDI, and this is the first time I needed any parts.. thanks

shak911 said:

where is the best place to shop for VW parts in the Toronto area, I am new to VW and TDI, and this is the first time I needed any parts.. thanks

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DCB Automotive and Precision Tuning for service & new parts, The Source for used parts.

Simon

I pulled my a/c compressor a few weeks ago and decided to check my regulator. My 180k mile one is next to a next to a new one. Over all the a/c compressor and alternator was very easy, or at least a LOT easier than a G60's a/c compressor swap.

may you please list the tools needed? dont want to start this and lack one tool.
I have most metric tools, just wanna make sure there isn't a funky bent extension or something...

However, I'm far from doing this. First, gotta play with multimeter and check all connections.


thanks