Originally Posted by Papa
We have a WFCO-9865 converter in our 2011 Mountaineer that has started making a strange humming noise intermittently before the fan kicks on. Along with this we notice that our 12v lights will brighten and dim when the converter in providing power. The lights do not do this when running on the battery, just when the trailer is connected to shore power.
The humming/buzzing noise will come on 2-3 times and finally the fan will start. Am I looking at a failing converter?
Unless there are other symptoms to indicate a problem, it's likely just a transformer that has some loose laminations. It shouldn't happen, but isn't dangerous, just annoying. If it bothers you too much, a new better converter is not expensive.
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