I found the answer in this forum, indicating the re-ground the wires. It is a temporary fix for me only.

In my situation I finally figured out that, the fault stems from the short of the stop switch wires, at where them inserted into the mainboard. The wires became faxed and abut to each other. I use glue gun to put a chunk of glue in-between making sure a good insulation persists. It went well afterward. It is not really due to where the grounding screw is. to loosen and re-fasten basically only does "re-grounding", not fixing the primary problem.

I cannot answer to the original post,therefore I post a new one to share my experiences.

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