Update on my FC!
 

So I've recieved my new idiot light cluster to replace the screwed up one.

Before installing it, I had the following problems...

When the key was turned, the lights did not illuminate at one time to show that all the lights are working... No clock. However...

The e-brake light was always very very dimly lit. If you pulled up on the e-brake, the brake light would go out and the add coolant light would get brighter. The add coolant light was on permanently, as was the charge light. The belt light did not work. If it did, it'd just remain on all the time regardless of whether the ignition was on...

Windshield fluid was on all the time.

Clock did not work.

After installing the new one.

Clock works.

When ignition is turned, the lights do not come on to self-check. From searching, I've read that this is the CPU that causes the horn not to work and the door/key beeper to not work or intermittently work. Considering that I do not have a working horn or beeper, I'm assuming that it's also not allowing the idiot lights to illuminate upon ignition.

What's the part number for the CPU I need?

Add coolant light does not come on as it did before right off the bat. After starting the car or ignition being on, it takes about five seconds before it comes on and it stays on.

All other lights seem to be working, but the low-fuel light is the one I want to really know about. How can I check that the low fuel light works?

A/C kicks ass. :-P

You can find the CPUs here:
http://www.mazdatrix.com/86-92Electrical-Chassis.htm

The Low Fuel light problem probably has to do with a bad sending unit in the tank. The FSM has instructions on how to check the gauge and sending unit in the Body Electrical chapter.

I had the same problem of the Low Fuel light not coming on. Later the fuel gauge started reading way below Empty. I replaced the sending unit from Mazdatrix and both problems were fixed.

Well my fuel gauge doesn't read right. When I fill it, it'll only go to 3/4. I've never run the car past 240 miles on a tank of gas, so I don't know if the light works to begin with.

wait wait, so the idiot light CPU ISN'T the same one for the horn and ignition beeper? I need my idiot lights to flash on once the ignition is turned on...

You might want to check for cold solder joints inside the idiot cluster too.

Too bad I can't solder my way out of a paper bag...

Might as well learn. Practice on something you don't care about first. Aaron Cake's website has a tutorial on it somewhere.

laguna seca backwards... I resoldered my idiot light cluster, and it's not too hard. You could come down this weekend when you're off and I could teach you... :)

my car does the same thing which prongs on the cpu do i solder my clock doesent work and the add coolant light comes on half the time and trips the annoying buzzer which is about to drive me crazy btw any ideas on how to trip around that buzzer??