300ZX If Your OEM Alarm System is Working

[speedslave]

I’d like to know if your Z has a working OEM theft alarm system. If you post your mileage and year that would be appreciated. Mine has stopped working for the second time. Per the shop manual went through the test steps 3 times now with same result to replace the control module. I have purchased 5 and returned them all because they did not work. I’m trying to decide if there is something wrong with my car that I’m missing or since these boards are 35 years old , always have power going through them there is a high probability that any used board is burnt at this point. Thanks!

[itsa300zx]

1990 NA, build date 03/89. 345000km OEM alarm still working.

[VStar650CL]

So where in the "System Operation Check" flowchart does it kick out? Does the lamp work? IIRC, on the 300ZX's the system won't arm at all if any of the sensors are stuck or inoperative. The most common failure points are the hood switch and (on later models too) the lock cylinder switches or mechanism. Exact symptoms would help.

[speedslave]

Thanks for the input guys. As far as my problem w my Z the alarm does nothing . No light ever, will not arm , nothing. Per shop manual checked at the harness and has power, has ground, checked all switch continuity all good. Switches checked are hood, doors, hatch, ignition accessories. With those steps passing the next step FSM states replace the module.

[VStar650CL]

For some reason the '90 FSM here seems to be missing the Theft Alarm section in EL. Is your system the same as the '89 (main and sub units under the passenger seat) or the '91 (single control unit in the passenger footwell)? The diagnostics for each are a little different.

[speedslave]

My Z is a 90 Turbo , shop manual for a 90 , security module in passenger foot well, alarm test procedure is in the EL section.

[VStar650CL]

I'm referring to the EL-116 (PDF page 1208) in the '91 FSM since Nico's '90 FSM seems to be missing the Theft Alarm section. I assume the Yellow wire has battery power, but have you checked White to make sure there's Acc power, and have you checked the pin-fits on the control unit connector? Crappy pin-fits are pretty common on old connectors, usually from broken or collapsed springs in the female pins. It would also be a good idea to check both power pins with a bulb-type test lamp, testing to the connector ground pin and not to the chassis. The bulb needs power, so if either one gives you a dim bulb then you know there's a resistance issue. In that case, check again to the chassis. if the dim circuit lights up bright, then you know the resistance is in the ground wiring, if it remains dim then you know it's the power side. Lastly, have you tried manually grounding the Purple wire to make sure the bulb works?

[speedslave]

I've only done the tests outlined in the shop manual, 3xs. I have purchased 5 used control modules none worked. Last year had the same problem purchased a used control module and it worked. This year when I reconnected the battery in the spring it didn't work. I will admit I haven't checked the bulb because I checked the actual arming of the system by locking the doors with the key and the driver window down. Once locked reached in to unlock the door which should have set of the alarm , nothing. Unless the system wont arm because the bulb is out then I would have a problem. Hmmm maybe I better check that, couldn't be the reason could it.

[VStar650CL]

Actually, it could. The system has a ground side drive for the bulb, so it may very well detect if the bulb is open. I don't know for sure, but we already know any flaw in the sensors will cause it to not arm. The same might be true of the bulb. I'd definitely do a pin-fit check as well, crappy fits and busted springs are very common on old rides.

[Daspyda]

'95 N/A, 122k miles, works perfectly.