I know this has been done to death, but bear with... The consumer unit [is that the right phrase] in our Starburst has a warning light to indicate reverse polarity. I bought an in-line reverser [right phrase again?] after a previous trip which revealed our Eberspacher heater didn't like RP. This did the trick on our latest Gallic excursion on the two occasions when the light came on. But then we reached a Belgian campsite. Hooked up, RP light came on - fitted in-line reverser - light came on again! Tried it twice to make sure I wasn't mistaken, but light resolutely stayed on whether or not the reverser was used or not. What on earth does that suggest? In the end I omitted the reverser and left it at that, but am fascinated by the physics behind it! Any suggestions?