VW beetle gauge and vibrator test in car with resistors

Testing a VW beetle OEM 18 ohm gauge and vibrator or 5.1 volt regulator/stabilizer.
The aftermarket 34 ohm gauge and 5.1 volt regulator/stabilzer will show the needle reading low by quite a bit.
If you use a modified regulator/stabilizer at 7.5 volt and the 34 ohm gauge it will cause the needle to read high and will peg the needle on full. Requires calibration to read correctly.
Measure the resistance of the gauge to verify.

[@darrenporter6862]

Really helpful. Thanks for posting

[@TEDodd]

How do you measure the gauge resistance? Just a mulimeter? How do you measure the vibrator/regulator voltage? My gauge (71 super) won't read empty with the sender (measured it at 73 Ohms). Disconnect the sender sand it does read empty.

[@vwbeetlefuelgaugesystem]

Dang, I missed that you replied to this video and thus left your hang. To measure the gauge resistance disconnect the sender wire from the sender or the gauge. Measure across the 2 terminals on the gauge... 16-18 ohms will show it being an OEM gauge. 32 ohms would be an aftermarket. Hard to read the vibrator voltage. You will need to use a jumper lead and attach it to the gauge where the vibrator attaches to the gauge terminal. The voltage will be jumping around, how much depends on the fuel level in the tank. More when the tank is full. So 0 to 2vdc to 7 or so... The regulator type which is plastic case and metal will show a constant voltage... 5.1vdc. Is you sender aftermarket? If so you should see if you have tightened the sender into the tank too far.. This video shows the issue... kzbin.info/www/bejne/rZOno5inZph4eK8

[@TEDodd]

@@vwbeetlefuelgaugesystem VDO sender. We exchanges some emails/messages later. Still not getting a low reading correctly. I'll double check the sender install. Have a new issue as my tank bulged after in replaced the cap. Reworked a vent short term, but tank is still high in center.