WFCO 9865 Repair

Yes WFCO's don't work out too well for some folks. I have replaced it with a 9200 series PD. Repair was an easy fix and I have other uses for it. Also have a WFCO in another RV and has performed flawlessly for years. Goes to 14.4v when it needs to and just does its job. Must be lucky. I think it is a 8700 series 55 amp.

Either way you are still stuck with a WFCO :(

Mex I haven't put any heat to it to check since I haven't determined where it should connect. I have a heat gun to check it but first I need to find where it should be connected. No evidence so far unless it is sending out some kind of magic rays...Ha.

The thermo fuse for my cheapo coffee pot was about the size of a one amp N1007 diode. Went series with the line voltage input. When the Borg gets finished my WFCO goes in for surgery if I can find that danged post on the forum that has images and values. But it gets a 10-turn pot instead of a fixed resistor. I cannot seem to find that info by searching. Frustrating. The Megawatts are getting heat sinks and fans today. Then le gran assemblie begins. Lots of wire to lay. Good luck with your own search.


Have you tested the device with a DMM and butane lighter?

I had decided it was a thermo device and it is normally closed but I cannot for the life of me find where it could have been attached. No loose leads or anything nearby. Unit operates without it which is strange since it is normally closed. Leads have been soldered to something at one time under the heat shrink.

This is apparently a thermostat, based on a bit of Googling. It should be normally closed, and open at high temperatures (at around 60C), and reset itself when it cools down again. I would guess that it was supposed to be in an over temperature shutdown protection circuit; 60C would be rather warm to start turning on the cooling fans.