Thanks Don, I should've mentioned the up force was at 9. I found and called the cust svc number 800-528-5236, and they made me lower the up force to 5, manually lift the door waist high and drop it. Since it slammed to the ground, their conclusion is that the door is not balanced and thus the GDO is doing all the work. they recommended a couple of repair guys to do what's called a Door Balancing. Does this make sense to you? Thanks again.

The wiring may not be conventional because the power or the light circuits are not coming into the switch boxes and some creative wiring was done. The easiest way to figure this out is to first disassemble all switches and lights to access the wiring. Find out which wires in each box have power and make a diagram. Next shut off the circuit so you can check each wires resistance/continuity. This will allow you to determine which cable is feeding where. With a voltmeter/DVM set to OHMS pick the first wire to check and make sure there is no continuity. With the meter still connected to the wire go to the light or switch box you think the wire is running to and touch the same colored wire to ground (this is assuming it hasn't changed color by a connection somewhere else). The meter will read close to zero ohms when the wire is touched to ground (some wires may read a low resistance if it is connected to the light bulb so you may want to remove them). Do this for each wire until you have a diagram showing where all wires are going/coming from. Then is is a matter of having the wire supplying power go to the common of one switch. The two other wires in that same switch box must get to the other switch. The other switch will have the two wires coming in from the first switch and then the wire going to the lights connect to the common of switch 2. It now is a matter of connecting the wires through all the boxes to achieve this configuration. If you cannot figure this out then a picture of where all the wires go to the switches and lights. Good Luck!

Folks, Thanks for the suggestions--they are good ones. I had never heard about the wireless solution, but perhaps that's a good answer. I did try a motion sensor switch with 180 degree coverage. I'm not sure whether the switch was defective or whether something (like the car) was interfering with it, but coming through the man door would not activate it. In fact, I had to be about halfway into the garage to activate it from the direction of the man door. The line of sight distance from the switch location to the man door is only about 20-25 feet (and the switch's range was claimed to be 40 feet), but as I said, the car was in the garage at the time. JKG

Wired incorrectly, while letting the fan use 2 return paths for neutral wouldn't be the end of the world, it is technically against code and unprofessional. The only way to wire the scenario with power first coming to the switch box is to also wire the fan to that first switch box. You would need 12/3 from the fan to the 1st switch box. Your other 2 switches controlling the fan would then be wired as a 3 way/ four way switch loop. Wiring needed 1st switch box: -12/2 from panel -12/3 to fan -12/3 to 4 way switch continuing to other 3 way switch. The light will then be using the red wire, connect it to the common terminal of the switch. Connect the white of the 12/3 heading to the other switches to the black incoming hot. At the 4 way switch, connect the white to the white heading to the last 3 way switch. At the last 3 way switch connect the white wire to the common terminal and the black and red to the other 2 terminals. At the 4 way you'll have 2 pairs of black and red to connect to the 2 pairs of terminals. The fan switch is easy, just connect a black to that same incoming hot wire that is tied to the white heading off to the other switches. Connect the black heading to the fan to the other terminal. The incoming power white wire will connect to the white wire heading to the fan. Yes it is complicated but it is the correct way to wire this. It simply comes down to the fan/ light not being allowed to use 2 different white/ neutral paths back to the source wire. The code only allows 1/0 and larger wires to be used in parallel, #12 wire is a lot smaller than 1/0.