Sorry the runtz failed but not surprised. I have a feeling the runtz has become the new Chinese ignition condenser. I'll give this subject some thought when I return home. There are several voltage reducers being sold on eBay and all of them appear to be the same design or a slight variation of it. It does appear to be a valid electronic scheme. If it is working on your heater fan, that is encouraging. The one criticism I had was it might not dissipate heat well enough, but the heater fan uses much more juice than the fuel gauge. Years ago VW decided to continue to use 6v fuel gauges in their 12v Beetles, although not many people knew it. Cost savings? You can decide...they used a voltage reducer similar to a common voltage regulator in the automotive generator circuit. We used to joke about them. Truth was they could have had the coils wound for 12v for a fraction of the cost of that vibrator device.
