Light Bulb Replacement On JVM 1860SF001

First thing is make sure you unplug the power cord. Turn the microwave around and remove the screws that hold the cover on. Remove the cover and look for where the power cord goes through the back of the unit. Follow the black wire coming from the power cord and that will take you to where the fuse is located. It might be on a small circuit board or mounted in a fuse holder or it might have an inline holder. Make sure that you replace the fuse with the same amperage fuse as you take out. You will find the amp rating stamped into one of the collars on the fuse. Good luck!

On some of these old GE Spacemaker models, there are two long horizontal bolts at the top (R&L corners), accessed behind the upper grill. Remove the grill (four tiny screws), take out the two bolts (flat screw heads) that attach to the rear plate, and your microwave will come right down and out, providing you've removed the three mounting bolts on the top.

Not sure as microwave manuals often will not discuss this due to consumer safety concerns, but here is some info from a good source on Microwave repair:

"You would think that something like replacing a light bulb would be trivial and self evident. Unfortunately, not always so with microwave ovens. Light bulbs may be typically located in any of 3 places:

1. Oven chamber - it may be behind a mesh grill requiring a screw or snap to be removed. This is the easiest.
   
2. Rear - the bulb may be in a recessed compartment accessible by removing a screw or two on the back of the oven.
   
3. Inside - it may be behind a non-removable grille requiring the removal of the cover.

These are typically not your usual vanilla flavored appliance bulbs either.

Bad connections are also possible but not that likely."

Remember, while you can do some repairs on your microwave, what you don't know can kill you... even on an unplugged microwave, so make sure you understand the dangers and how to reduce them before you try anything inside a microwave. If you want to do more yourself, follow the above link and take note of the safety instructions.

The owner's manual shows you to to access and change them.

Your exact model is not there, but the similar models (like the BCS suffix) should work just fine.

COOKTOP/NIGHT LIGHT REPLACEMENT

CAUTION

To avoid personal injury or property damage, wear gloves when replacing light bulb.

1. Unplug the oven or turn off power at the main power supply.
2. Remove the bulb cover mounting screws.
3. Replace bulb with 40 watt appliance bulb.
4. Replace bulb cover, and mounting screws.
5. Turn the power back on at the main power supply.

OVEN LIGHT REPLACEMENT

1. Unplug oven or turn off power at the main power supply.
2. Open the door.
3. Remove the vent cover mounting screws. (3 middle screws)
4. Slide the grille to the left, then pull straight out.
5. Remove the charcoal filter, if present.
6. Press and hold the center snap while lifting the tab on the left corner. Remove the cover. Remove
the bulb by turning gently.
7. Replace bulb with a 40 watt appliance bulb.
8. Replace the bulb holder.
9. Replace the grille and 3 screws. Turn the power back on at the main
power supply.

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

I think the key is pulling the vent to the left.

From page 36 of the online version of the owner's manual, which also mentions the active grille's presence on some models:

Oven Light

Replace the burned-out bulb with a 120 volt, 20-watt
halogen bulb (WB36X10213), available from your
GE supplier.

To replace the oven light, first disconnect the
power at the main fuse or circuit breaker panel
or pull the plug.

Remove the top grille by taking out the screws
on top of the grille that hold it in place and
sliding the grille to the left (opening the door
makes grille removal easier).

Next, remove the light cover.

On some models, the light cover is located
in the center of the top opening. Remove the
screw that secures the light cover and lift the
cover off.

On some models, the light cover is located at the
left of the top opening. Lift the cover off.

Pinch the clips that hold the light socket in
place and lift the socket out.

Remove the bulb from the light socket by
pulling straight out. Replace with the same size
and type bulb, then replace the light socket and
cover.

Replace the grille and screws. Connect electrical
power to the oven.

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

Here is the GE download page for your manual. Page 35 of your  manual gives the light bulb replacment instructions. 

http://genet.geappliances.com/DocSearch/Dispatcher

This is usually caused by either a bad door switch, a loose door switch mount, or bad door hinge alignment.

Even though a door switch clicks, it may still be bad inside. Its continuity must be checked.

Door switch or mount trouble can be caused by slamming the door or by opening the door while it's cooking without hitting the Stop pad first.

There are plastic mounts inside the microwave which hold the door switches and onto which the door latches lock when you close the door.

The screws on these mounts may be loose. If they get too loose, the switches will not be activated properly.

Sometimes it's a broken tab on the switch holder, allowing the switch to rotate just out of position. Other times, it's a broken tab on the switch holder, allowing the switch to rotate just out of position. This tab can be hard to see, since it is under the bottom edge of the switch.

One test that sometimes helps is to gently lift up on the door or handle as you try to start it. If it works or tries to work, then it's a door switch mount or door alignment issue.

If you or someone you know decide to look into it, we have critical information on safety, disassembly and door switches at our site, and our link is at our listing here on FixYa:.

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

There may also be a "mini-manual" hidden inside the unit behind the control panel or hidden on the left side behind the grille, which is very helpful when troubleshooting & testing.

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

That would be a problem with your primary interlock switch or its mount.

NOTE: There should also be a "mini-manual" hidden inside the unit behind the control panel or hidden on the left side behind the grille, which is very helpful when troubleshooting.

If you or someone you know decide to look into it, we have critical safety information, info on door switch diagnosis and replacement, and disassembly information at our site, and our link is at our listing here on FixYa: http://tinyurl.com/yzjozk

The interlocks are highlighted in the diagram below.

We're happy to help and we appreciate your thoughtful rating of our answer.

1 take the front grill off. 2. you will see a cover with one screw around the area of the light. normally this is right in front.

I just installed a JVM 1540 with the same grille. I removed the two top phillips screws before mounting the oven as I cannot access these screw heads once the oven is installed. It took me about 20 minutes of fiddling with the grille to figure out (no thanks to the manual) that the grille needs to slide to the left to release so you can change the light bulb/charcoal filter.