1972 theft alarm.

[Jerome E Pederson]

The theft alarm system when it is turn on; the theft alert horn immediately sounds. The hood and both door alarms switches are in a manually closed postion. I did this manually just to make sure the switches did close and not just rely on the doors and hood fully closing, although they do.

Anybody got a quick and simply way of checking out what is wrong?

JERRY

[Dick W.]

Re: 1972 theft alarm.

Probably as good a way as any would be to disconnect the alarm switches, one at a time until you (hopefully) find the culprit. It may be that you will find a wire disconnected from the switch and grounding out, therefore setting the alarm off.

[Jack H.]

What's wrong???

When any one of the switches close, that completes a path to ground causing the alarm system to fire. So, you say you've manually closed all three switches and wonder why the alarm sounds. It's supposed to! Now, if all three switches were open and the alarm fired, that'd be a problem...

[Jerome E Pederson]

Re: What's wrong???

I am probably am using the wrong words. I have, with help, pushed in each of the 3 switches simulating that the doors and hood are closed. released one and held the other two down. tried all combinations. The horn still sounds.

[Jim T.]

Re: 1972 theft alarm.

Jerry you have two plunger style switches in each door. The switch in the front door jam is for the interior lights only. The switch in the bottom rear of the door opening is for the alarm and door ajar light in the guage panel. Inspection and cleaning of the hood and door alarm switches may help with your problem. Removal of the wire terminals from the switches can be difficult. The terminal ends of the wires are designed to lock in when they are inserted into the switch, they do not just pull out.

[Jack H.]

Re: What's wrong???

When ALL are pushed down (switches open circuit), the alarm should stop. The switches run in parallel to ground, so any single switch closing indicates a theft threat (door or hood open) and sounds the alarm.

If the alarm sounds when all three switches are open, then you've got a fault somewhere in the system. A switch lead wire has skinned insulation and is making contact to ground somewhere, one or more of the switches are defective and aren't actually opening when you press them, Etc.

The last situation (switch not really opening), isn't all that uncommon. These switches were 'intelligent'. The plunger mechanism can move via interference fit inside the switch mounting barrel. When delivered fresh/new, the plunger assy was all the way forward in the mounting barrel (switch plunger protrudes to max length.

The switches were installed and connected, then the door(s) and hood were slammed shut. That caused the switch plunger to be pushed back into the mounting barrel and the switch 'remembered' the exact physical geometry of that door/hood.

Now, if a door or hood has been 're-adjusted' and the switch wasn't 'reset' (gently pull the plunger back out/through the mounting barrel), you can easily wind up with a situation where the door/hood is actually closed but the switch is NOT open circuited and the alarm is triggered even though the doors + hood are actually closed.

But, you already knew about this aspect of the system since it's identical to the door jamb/interior light situation...

[Jerome E Pederson]

Re: What's wrong???

Thanks Jim, Dick and Jack. I'll give it a try.