TheSamba.com :: View topic

Sat Jul 12, 2025 3:00 pm

Hi all,

Stock 71 1302s.

Fuel gauge has been having some issues. The gauge itself has been showing the correct fuel level. However, upon accelerating, the fuel gauge will slowly move to show full. Take your foot off the gas, or sitting at idle, and it goes back down to the correct level.

What’s been done so far:
- replaced fuel sender and done ground test by disconnecting wire and grounding on another ground point. Needle moved slowly but showed full.
- checked the resistor/vibrator while removed from vehicle - resistance between male and female spade are reading 3 ohms. According to another post I read on here, it should be zero?

There don’t seem to be any other posts on here relating to this specific issue - seems weird and I do hate electrical issues!

Have ordered another vibrator/resistor just in case too.

Sun Jul 13, 2025 4:49 am

The original stock “vibrator” is a pulse-style voltage regulator. It works by turning off and on several times a second, and thus reduces and regulates the incoming voltage down to the equivalent of a steady ~5 volt level (RMS average). You can read more about them here: https://www.speedyjim.net/htm/fuel_ga.htm

Anyway, it sounds like you might be having an issue w/ the vibrator unit - ? If so and you decide to replace it, note that most of the currently available aftermarket fuel gauge components for VW Beetles are often of poor quality and/or are not calibrated correctly, and thus can cause all sorts of issues & malfunctions in the fuel gauge system. I’d recommend sourcing and obtaining a good used or NOS original unit, if possible.

Sun Jul 13, 2025 10:17 pm

baldessariclan wrote: The original stock “vibrator” is a pulse-style voltage regulator. It works by turning off and on several times a second, and thus reduces and regulates the incoming voltage down to the equivalent of a steady ~5 volt level (RMS average). You can read more about them here: https://www.speedyjim.net/htm/fuel_ga.htm

Anyway, it sounds like you might be having an issue w/ the vibrator unit - ? If so and you decide to replace it, note that most of the currently available aftermarket fuel gauge components for VW Beetles are often of poor quality and/or are not calibrated correctly, and thus can cause all sorts of issues & malfunctions in the fuel gauge system. I’d recommend sourcing and obtaining a good used or NOS original unit, if possible.

Thanks heaps - I have ordered an aftermarket one for relatively cheap so I'll install when it arrives and see what the story is. If it is the vibrator unit, I'll order a NOS one too.