Okay, so I tried searching for this, but found no results that described this specific problem.

Car is a 1990 GTU, the security system light has been on since I've owned the car, it was stolen 3x from the previous owners, and the ignition was ripped out.

I've replaced the ignition, but I don't have a key to the door at all, so we never lock the car.

Tonight after dinner, I go out and try to start the car, and the accessories work, but when you try to crank over the engine, it cuts all power to the car.

I've had the car for a year and have had no problems with it this entire time until tonight. I'm thinking someone tried to tamper with it while I was at dinner or something? Anyway...if anyone has had this problem, or knows how to easily fix it, let me know.

 

I had that issue (without the alarm light constantly on, quite the opposite and only happened when cold). It ended up being a bad CPU board. Removing the ground cable from the battery for 30 seconds should get you back to normal. I would also make sure non of the cables are damaged at the point where they enter the firewall on the drivers side (try wiggling the giant harness to make sure it isn't wiring related).

http://mazdatrix.com/86-92Electrical-Chassis.htm

I can't guarantee a new CPU will fix your issue, if you open yours up (located in drivers kick panel) you should see leaking capacitors and burned out components if it's bad. I never found out exactly what was happening, but can assume the CPU board was short circuiting the power somehow. When I opened it up, it was all toasted. The fact your alarm light is always on says to me its also CPU related.

 

Sorry, disconnect both the positive and negative cables for 30 seconds.

 

I've disconnected both of the cables, and still it doesn't work.

I've checked some of the wiring for the CPU and it all looks good as well...

 

Did you open the cpu and looked at it?

 

No I haven't opened it up, it's cold, windy, and rainy outside. I'll wait until tomorrow to do that.

 

also forgot to mention, i would check the ignition harness since it seems you have replaced it in the past. I didn't have an issue with mine, but would also be a place to start for you.

 

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/wtf-thing-939371/

not sure if the s5 is the same as the s4 system ,, but worthy of a look

 

Okay, so I've unplugged the security system supposedly from the CPU, the top plug... and it's still acting up.

I'm starting to think it may be the starter shorting things out? But it's not doing it the way that my s4 had it happening either...

ALSO! This random occurance has started happening now too. Whenever I open the door, this sound plays... whenever I close the door, it stops... may have to turn the volume up to hear it.

http://s95.photobucket.com/albums/l1...0207011449.mp4

 

The alarm sends a signal to the Starter Cut relay which allows the signal from the ignition switch to make its way to the starter so the car can be cranked. You need to locate this relay and jumper one of the two Black/Green wires at this relay to the Black/Blue wire in the relay plug and try to start the car as doing this will bypass the alarm systems ability to prevent the car from being started. Now as far as the relay is concerned there are two Black/Green wires to choose from and you need to pick the one which "does not have voltage w/key to on." So when the key is turned to on then identify which B/G wire doesn't have voltage and jumper that wire to the Black/Blue wire and start the car. This relay is located next to the Main relay and the has one plug with four wires in a six pin plug. When jumpering the two wires the plug "does not" need to be plugged into the relay.