Last I wrote my 2000 Miata was broken down (stopped running and would not start) and towed to a dealer in Shreveport, LA. After changing out the fuel pump relay and computer to no avail, they diagnosed the problem as damage to the fusebox and wiring somehow caused by the after market alarm. They wanted to replace the wiring harness which would not be covered by my extended warranty, at a cost of approx. $3,000.
I picked the car up and trailered it to the dealer in Houston where the car was purchased. They quickly found the problem- the bolts holding the A/C compressor to the bracket had worked loose and fallen out. When the A/C was turned on, the compressor came forward and broke off the crankshaft positioning sensor. Replaced same and car now ok. They did have to replace the computer, but only because the other dealer had shorted it out in their troubleshooting attempt. The dealer found no damage to the wiring and nothing wrong with the alarm. They fixed everything under warranty, cost $ zero. Go figure!
Clark Smith