After noticing rather lacklustre performance from my engine heater, I contacted DEFA to see how to see how I could diagnose the problem. I checked continuity from the power cable and inter-connector all the way to chassis/ground, so power was getting to the unit.
Knut from DEFA provided a handy photo (from my blog!) with instructions to show how test with a multimeter. (Remember, I can’t take it back to the authorised DEFA agent who fitted it, since Waeco-Dometic sell coolers in Australia, not heaters.) The heater should present 170-180Ω between pins 1 and 2 and there should be no continuity between Ground and either 1 or 2. Measuring under the car wasn’t easy, but it was enough to show that the heater was dead. I checked again after I pulled it out to be sure.
Soon I got a brief message about the replacement, “FEIL : Brudd i sikring Kontaktvarmer”, which seems to translate as ‘Broken fuse in contact warmer’.
About 15 days later I received a new 413840 engine block heater from DEFA Norway under warranty. They added a 460372 “Installation kit” or heat shield, which wasn’t fitted before. BTW, I have no idea how to use the copper wires to secure the heat shield in the manner of jubilee clips.
To help removal I had purchased a garage creeper. Unfortunately, despite its low profile design it takes me very close to the under-tray while the car rests on stands. There is a small service flap in the under-tray secured by three panel pins directly below the mounting point. After a bit of a struggle, the replacement was in place. A quick test with a power meter on the socket showed 330W, just like the original.
It’s starting to get cold in the mornings. Already there’s been 9 days in May at or below 0°c. While the garage rarely gets below 5°c, pre-warming makes a difference, especially with my wife driving to work each day.