Vibrating When Light Is On: Troubleshooting Guide

When I turn on the lights, it starts vibrating terribly (even the exhaust system starts vibrating). The engine is a 1Z in a Passat 35i. Could this be the infamous tensioner pulley for the ribbed belt?

Best regards, WarLord.

I've been experiencing the same issue recently. The timing belt and serpentine belt were replaced 4 weeks ago. I suspect it's the tensioner pulley.

What happens if you turn on the rear window defroster (which has roughly the same power consumption) instead of the headlights?

Okay, and one more thing: In my case, for example, if I increase the idle speed to about 1000 RPM, the fuel consumption drops significantly.

It's the same for me.

@Martin R

I'll try that out.

Best regards, WarLord.

Hello, Does the alternator have a freewheel mechanism in the pulley? If not, please install one.

'How can I identify it? How do I replace it? What's different about it? What advantages does it offer?'

Best regards, WarLord.

Hello, you can identify the freewheel by the fact that the pulley can rotate freely in one direction without the alternator shaft rotating with it.
Sometimes, the 'friendly' free-flow exhaust system is not available for all engine codes, but other models may also fit.
First, remove the belt and rotate all pulleys and rollers to identify and limit any potential damage.
Based on my experience, this problem can occur after approximately 100,000-120,000 kilometers, even though there was no noticeable issue beforehand.

To the best of my knowledge, the 1Z models (at least the older ones) do not have a free-running feature.

He only came with the AFN.

The retrofit costs approximately 90 euros.

I've left it alone so far, but I've also thought about it.

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