in the 1991 mazda miata. why does the "dome light" stay on and the "door ajar buzzer" also stays on when the car is on or off and the doors are closed? anyone help!

 

It sounds like a door jamb switch. They are a simple make/break switch held on by 1 phllips screw. Remove one at a time til the light goes out.

 

You can try the thumb test first, it's really easy. Leave a door open, then push the black neoprene plunger right in as far as you can, and see if that turns the light/ buzzer off. Then try the door and see if it does the same. If both tests fail, you have a switch/wiring issue. if the thumb works but door doesn't, you have a tolerance problem. Putting a small piece of that black neoprene closed cell self-adhesive door draft sealing strip on the door, directly opposite the plunger switch is often a quick easy fix.

 

I really appreciate the two responses I recieved. Thank you both.
I tried both suggesstions to no avail. The buzzer and dome lights still stay on. I disconnected the buzzer so I don't go nuts. However the problem remains. The dome lights stay on when the doors are closed while the key is in the ignition. could the problem be the ignition??

 

In that case I would have to guess that one of the wires came off a door switch and is now grounding out by itself completing the circuit to the light/buzzer and causing the door jam switch to be ineffective.
You will have to remove the switch(es) to verify my theory.

 

OK, yes, it can be the ignition switch (or just a worn segment on the ignition key). Before getting to the dirty part, suggested by Virgin 1, you could try the following:
1. Squirt a good shot of contact cleaner into the key slot and tumbler interface of the switch and turn the switch to work it in well. Let it dry, then follow up with a light shot of powdered graphite (sold by bike dealers for lubricating bike chains), repeat the key turning process to work it in.
2. Assuming you have a spare key, try using it instead of your "everyday key" to see if it lifts the offending switch pin.
I caution though that while this MAY resolve the problem, if it does not, you still can't assume that the ignition switch is NOT the culprit.
What you are looking for is a pretty "hard ground" to chassis in the door switch circuits. It's an odd fault because the usual problem is the opposite i.e. the door switch contact is degraded and the courtesy light WON'T come on.
You don't give us much history. Did your problem occur suddenly? Does the courtesy light flicker? Does the buzzer emit a robust sound, or is it sort of a bit hesitant?

 

Would the door buzzer and interior light be controlled by the ignition switch (central electronic location) back in '91? I would figure that to be an old-school electrical system.
Also, does the interior light stay on even when the switch is turned off?

 

I think that vintage was all hard wire and relay logic (the newer software cars typically have a delayed light dim down/ turnoff after about 20 seconds from door closure). You have raised a point though. I've had sticky relay contact problems with turn/ hazard relay located high up on the inside firewall between the clutch location and driver's side door. If there is a buzzer relay it would probably be located in that same area. A test would be to turn the flasher on and feel around for the clicking relay, then see if there are similar shaped devices in the same area and give them a sharp rap with a screwdriver handle, or remove it and test them.
On my '99 XL there was at least one relay beside the flasher (the headlight flasher I believe.)

 

I just did a check on my '99 protege (door/courtesy light/buzzer/ignition switch are all normal). By leaving the key in the ignition and the door open and by 'closing' and 'opening' the door using my thumb on the door switch, I was able to determine that there is a relay involved in the system.
The relay click-click was synchronized with the buzzer bleep-bleep, and it's up under the dash in the steering column area.
When the key in/door open scenario applies, the buzzer should bleep in pulses. If it sounds a continuous bleep that would suggest to me that the relay might be hung up.