Where are the primary, secondary, door, and monitor interlock switches located at. I see the 3 located near the door latch area., missing a fourth?

Check for split wire's in door an for change in CIG lighter.

Sounds like a Whirlpool model (you didn't mention your model number), and apparently one of those with the overdesigned door switch circuits.

See sample photo below.

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.

You can find helpful exploded view diagrams and order parts by entering your full model number here.

We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.

Hi,

It sounds like one of the door micro switches is bad. There are three micro switches typically. A primary interlock, a secondary interlock and a monitor switch. It is most likely the primary or secondary interlock switch. You may need to take your switches to a professional appliance shop to determine which one is bad.


Let me know,if needed further assistance.

Hope i helped you.

Thanks for using ' Fixya ' and have a nice day!!

There are three to four switches that monitor that microwave. If any of them are bad it won't work. More then likely it's the monitor switch. There's a primary and a secondary switch. Take the cover off and look for the tech sheet it will show you which ones they are. They are around the door latch area...good luck.

I strongly suggest that you do not attempt to adjust the hinges.

The door switch mounts are either cracked or need to be adjusted.

Door switch mount trouble is usually caused by slamming the door.

This may be a little more info that you need and it's from a Sharp service manual, but the general principles apply:

1. Disconnect the power supply cord, and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor.

If the door sensing switch, secondary interlock switch and monitor switch do not operate properly due to a misadjustment, the following adjustment should be made.

4. Loosen the two (2) screws holding latch hook to the oven cavity front flange.

5. With door closed, adjust latch hook by moving it back and forth, and up and down. In and out play of the door allowed by the upper and lower position of the latch hook should be less than 0.5mm. The vertical position of the latch hook should be adjusted so that the door sensing switch
and secondary interlock switch are activated with the door closed. The horizontal position of the latch hook should be adjusted so that the plunger of the monitor switch is pressed with the door closed.

6. Secure the screws with washers firmly.

7. Check the operation of all switches. If each switch has not activated with the door closed, loosen screw and adjust the latch hook position.

After adjustment, check the following.

1. In and out play of door remains less than 0.5mm when in the latched position. First check upper position of latch hook, pushing and pulling upper portion of door toward the oven face. Then check lower portion of the latch Figure C-3. Latch Switch Adjustments hook, pushing and pulling upper portion of door toward the oven face. Both results (play in the door) should be less than 0.5mm.

2. The door sensing switch and secondary interlock switch interrupt the circuit before the door can be opened.

3. Monitor switch contacts close when door is opened.

4. Re-install outer case and check for microwave leakage around door with an approved microwave survey meter.

We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.

As per a similar manual:

1. Microwave leakage limit (Power density limit): The power density of microwave radiation emitted by a microwave oven should not exceed 1mW/cm2 at any point 5cm or more from the external surface of the oven, measured prior to acquisition by a purchaser, and thereafter (through the useful life of the oven), 5 mW/cm2 at any point 5cm or more from the external surface of the oven.

2. Safety interlock switches: Primary interlock relay and door sensing switch shall prevent microwave radiation emission in excess of the requirement as above mentioned, secondary interlock switch shall prevent microwave radiation emission in excess of 5 mW/cm2 at any point 5cm or more from
the external surface of the oven.

You need to be sure that if the meter comes with a styrofoam cone tip, that should be installed or it will give high readings.

Also, the meter should be calibrated periodically, typically annually.

If the meter gets dropped or bumped, that may throw it out of alignment.

The most common causes of excessive leakage are loose or misaligned door switch mounts or hinges and physical damage to the chassis of the oven.

The most common cause of the misalignment of door switch mounts is slamming the door.

I would be sure my meter is set up and calibrated, then I would be sure my door switch mounts are aligned & tightened properly.

From a similar manual:

1. Disconnect the power supply cord, and then remove outer case.

2. Open the door and block it open.

3. Discharge high voltage capacitor. If the door sensing switch, secondary interlock switch and monitor switch do not operate properly due to a misadjustment, the following adjustment should be made.

4. Loosen the two (2) screws holding latch hook to the oven cavity front flange.

5. With door closed, adjust latch hook by moving it back and forth, and up and down. In and out play of the door allowed by the upper and lower position of the latch hook should be less than 0.5mm. The vertical position of the latch hook should be adjusted so that the door sensing switch and secondary interlock switch are activated with the door closed. The horizontal position of the latch hook should be adjusted so that the plunger of the monitor switch is pressed with the door closed.

6. Secure the screws with washers firmly.

7. Check the operation of all switches. If each switch has not activated with the door closed, loosen screw and adjust the latch hook position.

After adjustment, check the following.

1. In and out play of door remains less than 0.5mm when in the
latched position. First check upper position of latch hook, pushing and pulling upper portion of door toward the oven face. Then check lower portion of the latch hook, pushing and pulling lower portion of the door toward the oven face. Both results (play in the door) should be less than 0.5mm.

2. The door sensing switch and secondary interlock switch interrupt the circuit before the door can be opened.

3. Monitor switch contacts close when door is opened.

4. Re-install outer case and check for microwave leakage around
door with an approved microwave survey meter. (Refer to Microwave Measurement Procedure.)

Please write back with more details if you need further help.

We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.

The Interlock Monitor Switch is an added
safety check on the Primary and
Secondary Interlock Switches. If the
Primary and Secondary Interlock Switches
allow the oven to operate with the door
open, the Monitor Switch will blow the
fuse.

You can get more information about adjuting the interlock switch from this link

http://136.166.4.200/contents/Microwave/LMVM1935xx/LMVM1935xx_Service_Manual.pdf

sections 7-11 thru 7-12 discuss the door interlock adjustment that will cause the 20A fuse to blow if it isn't set up right. I hope this helps you...

I've had this problem twice with our microwave. The hint to where the problem lies is that the breaker blows when you open the door at times. Inside the microwave are three microswitches; primary and secondary interlock micro switches and an Interlock Monitor switch. The switches are supposed to shut down the microwave if it is running and the door is opened. But, I've found the upper primary switch can stick internal at times and when the door is opened the stuck switch will, because of the way it is wired as a safety switch, cause either the fuse or possibly the main circuit breaker for the oven to pop. The reason the stuck switch blows the breaker or fuse is when the door is opened the interlock switch will cause the neutral wire from the AC power to be applied to the Upper Primary Interlock switch which normally should be open when the door is opened, but if the switch is intermittent or the contacts weld themselves shut the neutral line is connected direct to the "hot" side of the power line through the fuse and thermostat. The first time my microwave failed the switch had melted the contacts together inside the switch and the second time the switch became intermittent and would blow the breaker to the over ever so often. I suspected the switch the second time this happened and utilizing an ohm meter I checked the switch several times by opening and closing the door and once in a while it would remain closed instead of opening when the door was opened. Of course while trouble shooting the power cord to the microwave must be disconnected and use all safety precautions when working around the high voltage areas inside the microwave. I wrote Jenn-Air about the bad switch and the way it is wired into the circuit, but never received any acknowledgement. I suspect these microswitches are under rated for the amount of current that passes through the switch, thus they overheat and eventually arc the contacts together. I hope this helps explain the intermittent problem and could explain many of the intermittent blown fuse problems I see in these internet help sessions

Waleed, Since the microwave is going through all its motions we can feel safe that the oven and magnetron thermostats are ok. If they were bad you would not have a display. Just inside the control panel to the left, you have 3 switches which the door activates. A primary (top switch) a secondary (bottom switch) and a monitor switch (middle). If the primary or secondary switch is not closing when the door is shut, you high voltage side will not activate, therefore no heat. If the monitor switch failed or found either the primary or secondary switch closed with the door open, it would blow the main fuse and the oven would be dead. Therefore Im leaning on either the primary or secondary switch not operating correctly. When checking these switches, unplug and discharge the capacitor. This is high voltage. Good luck