73 Coupe anti-theft problem

[George W.]

I have a problem with the anti-theft system on my early built (Sept) 73 coupe. It works correctly when opening the drivers door or the hood, but does nothing when the passenger door is opened. The door jamb switch works correctly and activates the courtesy lights.

The driver and hood switch have two connections, black and white. The passenger side has only the white. I have the AIM and Service manual and my wiring matches the service manual.

Has anyone had a similar issue and how did you correct it. The car is to be judged at Frisco (first time for flight judging for me and the car) and any thoughts or suggestions will be greatly appreciated.

The anti-theft horn is not an original but performs fine for the driver side and hood. The wiring diagram shows the anti-theft horn with a yellow wire attached too the body of the horn then attached to the body. Is this attachment too the body grounded?

Thanks
George Walker

[Edward J.]

Re: 73 Coupe anti-theft problem

George, I have a 72 and the alarm horn has its own ground wire attached to the base of horn. Does 73 have a door ajar light on the dash, The reason I ask is this seems to be the signal that activates the alarm when door is open, and the switch on 72 is located at the rear part of jam, not the front part of the jam. Does 73 use the two switches on each door? The front jam switch is the key buzzer and dome light on my 72, rear switch work the door ajar light and Alarm.

[George W.]

Re: 73 Coupe anti-theft problem

Edward thank you for your reply. The 73 does have a door ajar light and switches both at the front and the rear. The 73 AIM indicates the the two front switches along with the hood switch activates the alarm. But sometimes the AIM is not completely accurate. I will check the rear switch on the passenger side in the morning and post my findings.

George

[Robert R.]

Re: 73 Coupe anti-theft problem

The door light and door ajar light are activated by the switch in the front of the door. The alarm is activated by the rear switch.
Hope that helps.

[Kurt G.]

Re: 73 Coupe anti-theft problem

George, like Robert said, there are two separate switches. The one for the alarm is located on the door frame panel at the rear side of the door opening. To access the switch you will want to pull off the right rear tire, then remove the small rectangular metal plate on the front side of the wheel well. 4 small screws. The back of the switch is accessible thru the opening. I'm betting you'll find the switch is bad, or a wire is loose or broken. It's a somewhat common problem. Ask me how I know. While you're in there check the body bolt. If its rusty news a good time to squirt some PB Blaster or your rust inhibitor of your choice, just in case you ever decide to yank off the body.

[George W.]

Re: 73 Coupe anti-theft problem

I checked the rear door switch and that's the problem. The plunger switch is the only one I had to replace and as is the case with so many reproduction parts it does not work correctly. The originals have a base with a captured washer that moves and allows three connectors to make solid contact. The replacement does not and getting all three connectors to make good contact is hit or miss.

Thank you all for the help.

George Walker