Switch &wiring terminals have burnt out leaving two brown wires and one fine grey wire. I know where the gray one goes but how can I identify the two Brown wires which are hanging loose Hope you can help Thanks Gordon

Bad door switch! If you look at the switches where the terminals come out of the switch body, you will probably see the plastic under the terminal coming out of the switch has melted, Maybe a bit of browning on the clear or whiteish insulator on the terminal,.you will need to repalce the bad switch and run better, larger wires to it to stop this from happening again. I use a higer amperage rated switch and I run nickel stranded high temp wire to it, with Commercial High temp terminals so it doesnt happen again.

Its back feeding power due to a bad door switch and connections to the switch. You have to unplug it, then remove the front panel . Look at the door switches, they should all snap back up if they are pushed down. If one doesnt, it is bad. Also look for browned or burnt wire connection to the switch. Poor wires and connection are the number one cause of door switch failure. I upgrade the switches to a switch with 1/4 inch terminals, these dang microwave companies are using switches with little 3/16 terminals and they just do not hold up/

Pulled up a schematic on this will try and help the first pic looks as though you removed the secondary switch the bottom one if so that is the wrong switch it should be a normally open switch that one is normally closed this switch goes up top on the other side of the primary switch the one with 3 terminals, look at the second pic the switch with 3 terminals that red wire in the wrong spot the skinny orange goes there the switch I just told you to put up top the red goes to one terminal the white and brown middle form the 3 terminal goes to the other terminal, the blue/white and blue go to the bottom switch this is a normally open switch if you don't know how to read a switch look at the switch look at com follow the line to where it stops if it is NO=normally open, NC=normally closed your primary switch is in the right spot you want the switch next to it to be NC and the bottom switch NO it blew the 20 amp fuse once you correct the switches and wiring and put in a new fuse if you have no power then it blew past the fuse and burnt out the filter board happens some times about 60 bucks let me know if this helps

Last time I opened a microwave there was a schematic taped to the inside of the housing. Good luck.

There should be a "mini-manual" (tech sheet) hidden inside the unit behind the control panel or hidden on the left side behind the grille, which is very helpful when troubleshooting, testing, and locating components.

The model JVM1330 schematic I have on file is a bit confusing.

It shows that the bottom door switch is the primary interlock, and its "C" terminal will have a black wire that goes to the main relay's tab on the control circuit board and a blue wire that goes to the oven lamp.

The "NO" terminal of that switch will have a black wire that goes to the "C" terminal of the middle (monitor) switch and a blue and/or black wire that goes to the internal cooling fan motor and a blue wire that goes to the stirrer motor in the ceiling of the oven.

The top switch is the door sense switch, and it will have thin wires. They may be pink, orange, etc, but they will be thin wires.

The schematic I have is here.

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Every microwave I've worked on has a wiring diagram attached inside the cabinet. The wires are usually just long enough to reach one switch.

Tell me what you are wanting to accomplish. Are you wanting to run each fan off a separate switch in the same duplex box? The reason I ask is because you are using 12/3 wire to the fans. If you are just going to have 2 switches then you are only going to have power to each fan from each switch. Therefore there is no need to run 12/3 wire. 12/2 is all that is needed and you would simply tie the fan and light wires to that one power source at the light/fan. Now if you are wanting to have a switch for the light and another switch for the fan at each location then that will take 4 switches. You can buy double stack switches and have 4 switches in a double gang box. Is this new construction or old? Please explain what you are wanting and I will be more than happy to explain how to wire it.

The problem is the push-on connector on the UPPER door-latch switch; if the white plastic around this connector is brown (burning), the connection is going bad.

Cut the three white wires back about 1 inch and strip; obtain a new push-on and solder the three white wires into it-- a crimp is NOT sufficient for three wires into this little connector (defective design). Also clean the two blade on the switch before reconnecting as the heat has likely left a burnt coating.

You can find helpful exploded view diagrams and order parts by entering your model number here: http://tinyurl.com/gv383 When a microwave is not heating and is making extra noise, it's usually a bad magnetron or high voltage transformer. But once you've looked over the documentation I pointed you to, let us know if you still have trouble.