Ruud Model # UGED-06EMAES Serial # BU50703 M47922089 * I had the top cover off for a day or two making sure that the furnace was working properly before putting it back together. I had some time today, so I wanted to do a leak check, even though I had not removed or changed any of the gas lines. I also tightened the screws where the 18 gauge wire connects to the board. There is a single green light on the board that simply shows that the board is receiving power. It does not blink error codes. * I am not sure if it gives you any clues, but, while tightening the screws to the IFC, my screwdriver rubbed against the sheet metal box that surrounds the board, and I saw a spark. * In any case, the t-stat had been set back to 60 degrees at this time of the day. In order to test for leaks, I set the t-stat to HOLD 75 and went back to the basement to check for leaks. I waited and waited, but the furnace never even attempted to come on. I went up and checked to make sure the t-stat was set correctly, and it was. I reset the breaker, I turned off the kill switch for 10 seconds and then turned it back on, and nothing. I have two limit switches on this furnace, and both show continuity. I checked the leads going to the inducer, and I show no voltage. At the board, I show 125 volts between hot and neutral (at the connectors on one edge of the board where a humidifier would connect). I followed the incoming leads to the transformer, and they also show 125 volts. The output of the transformer shows 27 volts. * In measuring the wiring contacts, I have the following with the t-stat calling for heat: ·******** R-C ***-* 27 volts ·******** R-W **-* 0 volts ·******** C-W** - 27 volts * There are also G and Y contacts, but they show no voltage regardless of which other contact I touch. As I understand it, the G only gets energized when the board calls for the blower, and I believe the Y is for air conditioning. * I have seen a video that mentioned a fuse on the board, but I do not see one. Before removing the board from its metal box, I wanted to know if it is possible that there is a fuse mounted on the back of the IFC. * Thanks for any light you may be able to shed on this for me.