See http://www.miata.net/garage/miata_radio_removal.html
Take off the airbag on the steering wheel, there are 2 wires, remove the black one....I think its the black one, well remove one then see if the light is still on
Side of your steering wheel, and on the switch youll see stamped "CRUISE CONTROL" and "ON-OFF"
On a 1991 Miata, the battery is in the trunk. It is probably the same on the 1990.
Here are step by step instructions and how to changer miata starter : http://www.racecaddy.com/mx5/tech/starter-mx5.html enjoy
remove the panels in the boot across the back and you will se them behind there
remove wheel
The 1990 model of Miata came with a 1.6L DOHC engine and produced around 120 horsepower.
Unless there is an access panel in the trunk then yes it must be removed.
My 93 only had a pan and no drain plug. I had to remove 14 screws and drop the pan.
Use the button on the dash to raise the headlights, remove the black plastic cover from around the headlight, unbolt the cover from the frame mechanism (IIRC).
Take horn apart, remove center nut & use a steering wheel puller (carefully, when they break loose, it can be fun)