A B737-300's Wing Body Overheat system wing sensor failed to test so contract maintenance used a cigarette lighter; near fuel fumes; to test the sensor. The flight crew had no say in maintenance or passenger dealings.

Narrative

Wing-body overheat test did not work. After Contract Maintenance did maintenance procedure 26-18A; the First Officer asked him how he applied heat to the wing-body overheat sensor in the wing. Contract Maintenance said he used a cigarette lighter. I called Maintenance Control and Maintenance Control said using a lighter was OK. Question: 'Is using an open flame in the wing of an aircraft with passengers onboard; especially when the MEL maintenance procedure warns about the possibility of fuel vapors in the wing; an acceptable maintenance procedure to activate the wing-body overheat sensors to verify their operation?' The First Officer and myself were told by maintenance that they would use a heat gun; but that later turned into a lighter. Maybe this is a standard procedure at our Air Carrier? How much responsibility do pilots have in trying to check and understand how maintenance works on their aircraft; especially when pilots are under court order to not intentionally (open to interpretation) slow down flight operations. Case in point; the first leg of my trip had a circuit breaker that was broken. A Maintenance Supervisor tells me they have to remove power from the aircraft (full airplane; no air conditioning) to do their work; and it will take an hour; so the aircraft needs to be deplaned. I walk up the jetway to tell the agents; who are on the phone with Ramp Tower; who tells them it is a 20 minute fix and do not deplane the passengers. I go back to the aircraft to tell the mechanic; and I call Maintenance Control to explain what is going on because I do not know who is in control -- Maintenance or the Ramp Tower? My understanding from what I have read is that pilots no longer have a say in the boarding of passengers. Maintenance replaced the CB with power on.