I have an Evcon BGM10016B furnace that we just started having problems with. The unit will kick on when i move the main 15 pin wiring harness around in just the right position. Is there anyway I can tell if it is a faulty connector at the board or in the harness? I would hate to spend 200 on a board when it could just be fixed with a new $60 wiring harness. Thanks!
Most connectors have a moldex connector with removable pin connectors held in place with tabs. Using a small screwdriver, you can remove the pin from the connector by pushing down on the tab while pulling the wire out. You may also want to check for mice chewed wires.
I'm not an HVAC tech but, if you're talking Molex connectors I'd bet on them being the problem before anything else. I spent 17 years maintaining wafer fab equipment and we finally got tired of the problems associated with those connectors and replaced them with Amp connectors. The ONLY reason companies use them is because they're CHEAP. They're tin, tapered pins and corrosion does them in. The taper fit also contributes to problems over time. Cleaning the pins, squeezing the female pin or expanding the male pin to improve the connection will help for awhile.
Sounds like a bad connection in the harness to me and I bet if you look at the pins in the Molex plug one of them will be a little bent out of shape, and you may be able to use a small screw driver to bend it back into shape and not have to spend any money at all on your furnace! Bonus! Also there is a small tang on the pins in the connector that if you push it in the entire wire will pull right out of the connector end and all. If you need to I would replace the harness before the board. I personally have had loose connections in those type of plugs too on many furnaces and air conditioners, and have yet to replace a harness because I usually find the bad connection/wire and adjust it or replace the individual pin in the Molex connector. You can get the pin tool and an array of pins for 15 bucks if you don't have one.
Woof has a good answer. Try this also; Cut any and all power to the unit and make sure the board is dead. This will be tedious. Use a very small wire pick or a micro o-ring pick. Get comfortable, get some very good light and get a very close look at the 15 wire plug, both male AND female. Use the small tool and spread out the male ends ever-so-slightly, and/or get in beside each and every plastic hole, pulling in the wall of the female end of the plug. When it plugs back in, it should be jam up and jelly tight. good connections equals proper operation. hope that helps
