My TDI's electrical problems - voltage regulator?

Now, my car needs some help. Last month, it threw its battery light on the dash. I replaced the OEM battery and the light remained. Then I had a local parts store run their test and was told the alternator was junk. I replaced the voltage regulator (Bosch) and the battery light went off. Now, the voltmeter shows 14.3 volts at idle. Funny thing is, electrical issues are now popping up. 1st, the car blew the brake lights' fuse, then the odometer and speedometer stopped working, and now the ABS light has come on. The car has 110k, which may be the bewitching hour, but I doubt it and suspect my voltage regulator is either incorrect or faulty. How can I confirm what is wrong? Thank you!

It should not be the voltage regulator, as the systems in question are not related in that way.

A couple of questions:

1) When you say the ODO and speedo have stopped working, is the display still indicating the mileage on the vehicle?

2) Has the brake light fuse blown again since that one occurance?

3) Did anyone throw the Vag-Com at the ABS light to determine its source?

I suspect that the fuse blowing at the same time may be a coincidence.

If the speed sensor in the trans goes belly up, then it should throw a CEL. If your CEL isn't on, then the connection between the ECM and the instrument cluster is suspect. If the ABS light is on, then perhaps the ECM is not getting a correct speed indication from the ABS module, and will not run the speedo while there is disagreement between what the ABS module says, and what the speed sensor says.

Hook it up to the VAG to get a better idea of what's going on.

-Rich

Rich, thank you for the feedback. Speedo does not move off of "0". Odometer is stuck at 110,xxx. Trip odometer reset itself to 0 and clock reset to 0:00. I checked all fuses again and #13 was blown again and I replaced it. ABS light is now out and I have all brake lights for the moment. Also, I forgot to mention when this happened the car lost some driveability. It lurches when accelerating lightly at low revs (1,000 - 1,400 rpm) but smooths out above that fine.

Also, what I did not mention earlier was I had U-haul install a simple trailer harness and I towed a boat east with the TDI 2 weeks ago. No issues at the time, but I wonder if that harness has anything to do with these electrical issues either. The install looks simple at tidy at the back of the car. I still wonder about the voltage regulator swap I did. Thanks again for your knowledgeable help. Cheers, Roy

1 more thing, my check engine light has been on for 2 years. I was told it was due to an exhaust leak near that cat, that is said to be a common, factory problem. I didn't catch it while still under warranty and instead had a private mechanic fix it with a weld, but no reset would hold on the CEL.

Roy- you don't list what year this Golf is, but on none of the years will an exhaust leak cause a CEL like that. Are you local? I'd like to scan it, and take a peek. Also, I'm going to research what circuit that fuse is on, and I'll get back to you. There may be something else afoot...

-Rich

callawaytdi said:

1 more thing, my check engine light has been on for 2 years. I was told it was due to an exhaust leak near that cat, that is said to be a common, factory problem. I didn't catch it while still under warranty and instead had a private mechanic fix it with a weld, but no reset would hold on the CEL.

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Re-read the code. A leak at the cat will not be detected by OBD. Only the EGR flow is indirectly monitored.

callawaytdi said:

...Also, what I did not mention earlier was I had U-haul install a simple trailer harness and I towed a boat east with the TDI 2 weeks ago. No issues at the time, but I wonder if that harness has anything to do with these electrical issues ...

Click to expand...

You can quit wondering. Go back and remove said harness, and repair every connection so that the wires are well connected back together and nothing is grounded that should not be. I'd bet someone did a job much too quickly and most if not all your problems are related to this.

Then you'll have to replace fuses, bulbs that are out. Maybe you'll get lucky and nothing else has been fried.