Jcpstrat

Thought I'd post my '74 Simplified Wiring info. here since there's lots of good info. in this thread and I just finished troubleshooting my system.



I had a hard time understanding/following the wiring diagram from my ’74 manual so I traced things out and created my own simplified drawing which really helped me.

Operation:
When the keyed Anti-Theft switch is rotated clockwise the system is armed. If the hood and doors are closed and the associated trigger switches are adjusted properly (switches open), nothing is energized in the system but you should be able to measure 12v at all points on the following wires:

14 – PNK
14 – YEL

When the hood or either door is opened (even momentarily), the Anti-Theft relay is energized, closing it’s contacts. Two simultaneous things happen at this point. The Anti-Theft horn starts pulsing (if flasher is good), and the relay contacts creates a circuit path to keep the relay energized even if the hood or doors are closed.

The only way to turn the alarm off after it has been triggered is to turn the keyed Anti-Theft alarm switch to it’s counter-clockwise position.

Jcpstrat

One other tidbit not to overlook "don't forget the connectors". My alarm horn was bad and the flasher actually had several holes in it's aluminum can so I replaced both. All the switches had already been replaced with recent total re-conditioning I've given my '74 and all the wiring, relay and fuse seemed to check out OK. I even tested the horn and flasher on my workbench with 12v across them in series and it worked and pulsated. Put it in the car and nothing. Then I took the horn connector and flasher connector apart and cleaned the contacts with a dremmel tool. I also took relay apart and cleaned it's contact surfaces. Put it all back together and bingo ... it works.

PGPierce

PGPierce

76 SR.!How dose the lock work ,Mine has a l shaped arm ,dose this move l- R? In and out?,how does it inter act with the switch that has 2 wires? I do have a keyed lock and tamper sw,but the key dosent work the lock,trying to find a replacement since the lock has no numbers to get a key made. Can't understand how this lock will switch on the tamper sw?

Jcpstrat

I don't have my '74 anymore as it sold so I can't double check this but I believe this is how it worked. I'm sure someone else will post if this isn't correct. On my '74, here's how I activate the alarm after I exit the car (hood and doors closed). The key slot in the front fender should be horizontal. Put the door key in the front fender lock and rotate it clockwise, to a vertical position, and then remove the key. To disable it just put the key in and turn it counter clockwise until it's horizontal and then remove the key. Good luck.