1974 corvette alarm
Thread Starter
Cruising
Joined: Dec 2024
Posts: 11
Likes: 0
1974 corvette alarm
Well guys I think I tried everything I’m trying to get my factory alarm system to work
had the car for 41 years
the problem is when you turn the key to the on position the alarm starts blaring
replaced all 3 switches
replaced the flasher in the car jack compartment the relay beside the flasher seems to be working if you turn the key to on position you can here the relay clicking so I’m thinking it’s ok
put a jumper on all 3 switches still the same
not sure if the problem maybe behind the actual key switch
kind of frustrating
any insight would be appreciated
had the car for 41 years
the problem is when you turn the key to the on position the alarm starts blaring
replaced all 3 switches
replaced the flasher in the car jack compartment the relay beside the flasher seems to be working if you turn the key to on position you can here the relay clicking so I’m thinking it’s ok
put a jumper on all 3 switches still the same
not sure if the problem maybe behind the actual key switch
kind of frustrating
any insight would be appreciated
Racer
Joined: Sep 2025
Posts: 470
Likes: 131
From: Colorado
Without knowing too much about it, the key switch should simply be open when key off, closed when key on. If the key in off position turns off the alarm, it tells me the switch is doing what it's supposed to do. If the alarm sounds when the key is turned on, something down the line must be activating the alarm.
Racer
Joined: Sep 2025
Posts: 470
Likes: 131
From: Colorado
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What about the (4th switch) tamper proof sensor that makes sure the alarm lock was not punched out?
It looks just like the headlight position switches and is mounted below the lock on the fender
It looks just like the headlight position switches and is mounted below the lock on the fender
Racer
Joined: Sep 2025
Posts: 470
Likes: 131
From: Colorado
I recently bought a '73 with alarm system but it's disabled. The key switch has been removed and wires just hanging there. I'll go out and try to get a handle on how the system works and try to give some better advice.
Pro
Joined: Dec 2015
Posts: 578
Likes: 107
From: colo
The door and hood switches are in a normally open position , so when you open the door it closes the switch and sets off the alarm. Unplug the power wire to each switch ( you should use a multimeter to find them ) and tape them off - so they don't short out. If the alarm stays off, then plug one switch back together at a time and test the system to see if it is working correctly.
Let us know.
Let us know.
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Racer
Joined: Sep 2025
Posts: 470
Likes: 131
From: Colorado
The door and hood switches are in a normally open position , so when you open the door it closes the switch and sets off the alarm. Unplug the power wire to each switch ( you should use a multimeter to find them ) and tape them off - so they don't short out. If the alarm stays off, then plug one switch back together at a time and test the system to see if it is working correctly.
Let us know.
Let us know.
However, when installed and with door/hood closed then the switch is opened. So, as long as considering doors/hood normally shut, then the switch will be normally open.
Last edited by zxryder72; Oct 20, 2025 at 10:04 AM.