1978 Possible Alarm Problem
Thread Starter
2nd Gear
Joined: Jul 2007
Posts: 2
Likes: 0
1978 Possible Alarm Problem
Hubs went to start my car, which is fairly new to me, and it appears that he activated an alarm system that I was not aware existed. I do not have a key hole on the front left fender, which I thought would show if it was a factory alarm.
Well, now the car won't start and every time we try to lock the car the alarm sounds.
Does anyone have a schematic for this alarm system, or know how to disable it so I can start my car?
Thanks! Mouse
Well, now the car won't start and every time we try to lock the car the alarm sounds.
Does anyone have a schematic for this alarm system, or know how to disable it so I can start my car?
Thanks! Mouse
Safety Car
Joined: Nov 2004
Posts: 4,359
Likes: 57
From: Mundelein Illinois
Put the key in the drivers door and unlock the door. When you unlock the door that disarms the alarm. To arm the alarm, just hit the lock button with the drivers door open. Alarm will set in 15 seconds after drivers door is closed.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Thread Starter
2nd Gear
Joined: Jul 2007
Posts: 2
Likes: 0
Yes
I have put the key in the drivers door. I have locked/unlocked several times. The car simply will not start, there is no power to the starter at all.
I have pulled the battery cable, hoping to reset, but that did not work either.
Every time I try to lock the door with the key, it activates the alarm. Right now, I have it unlocked. I feel fairly safe as if I can't start it the average idiot won't be able to start it either. LOL.
I am not your average woman, I can troubleshoot most problems, but electrical has never been my strong point.
My drivers window is slower going down then normal if that helps.
If I had a schematic, or at least knew where the fuse was I could probably bypass this alarm.
The book I have (Haynes) pretty much tells me what the alarm does, but not how it is set up.
Thanks!
I have pulled the battery cable, hoping to reset, but that did not work either.
Every time I try to lock the door with the key, it activates the alarm. Right now, I have it unlocked. I feel fairly safe as if I can't start it the average idiot won't be able to start it either. LOL.
I am not your average woman, I can troubleshoot most problems, but electrical has never been my strong point.
My drivers window is slower going down then normal if that helps.
If I had a schematic, or at least knew where the fuse was I could probably bypass this alarm.
The book I have (Haynes) pretty much tells me what the alarm does, but not how it is set up.
Thanks!
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
I have put the key in the drivers door. I have locked/unlocked several times. The car simply will not start, there is no power to the starter at all.
I have pulled the battery cable, hoping to reset, but that did not work either.
Every time I try to lock the door with the key, it activates the alarm. Right now, I have it unlocked. I feel fairly safe as if I can't start it the average idiot won't be able to start it either. LOL.
I am not your average woman, I can troubleshoot most problems, but electrical has never been my strong point.
My drivers window is slower going down then normal if that helps.
If I had a schematic, or at least knew where the fuse was I could probably bypass this alarm.
The book I have (Haynes) pretty much tells me what the alarm does, but not how it is set up.
Thanks!
I have pulled the battery cable, hoping to reset, but that did not work either.
Every time I try to lock the door with the key, it activates the alarm. Right now, I have it unlocked. I feel fairly safe as if I can't start it the average idiot won't be able to start it either. LOL.
I am not your average woman, I can troubleshoot most problems, but electrical has never been my strong point.
My drivers window is slower going down then normal if that helps.
If I had a schematic, or at least knew where the fuse was I could probably bypass this alarm.
The book I have (Haynes) pretty much tells me what the alarm does, but not how it is set up.
Thanks!
tiasd
Last edited by ...Roger...; Jul 16, 2007 at 07:52 AM.
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Drifting
Joined: Jul 2005
Posts: 1,891
Likes: 2
From: Baltimore MD
and as far as I know you can't find a replacment except at maybe Dr. Rebuilds.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
That doesn't help her now - does anybody know where the "Electronic Theft Deterrent Control Module" (Alarm ECM) is located on a 78? You should be able to pull the electrical connection and take the Alarm system out of the loop. I had to do this to mine - when I connect the battery the Horns just keep blowing and blowing. I checked everything and still could not shut this thing up. All my switches have checked out - I think the module just decided to go south I had to pull the plug on it and as far as I know you can't find a replacment except at maybe Dr. Rebuilds.
and as far as I know you can't find a replacment except at maybe Dr. Rebuilds.
Drifting
Joined: Jul 2005
Posts: 1,891
Likes: 2
From: Baltimore MD
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Racer
Joined: Nov 2005
Posts: 478
Likes: 0
From: Ellicott City MD
My 1980 has a cylinder theft detection module inside the door perpendicular to the lock cylinder that senses whether the lock is being jimmied. There is another cam-like electronic pigtail at the base of the door lock cylinder that is activated by the key turning in the lock. Turn to the left <=== sets the alarm. Turn all the way right ===> deactivates the alarm. When setting the alarm, turn the key back as verticle as possible and gently remove the key from the lock.
There is also a pin switch (door ajar) in both door jams. They both have to function correctly or the alarm circuit is compromised. The drivers side door ajar switch connects directly to the alarm circuit.
There is a relay under the center console beneath the ash tray area. An issue with any and/or all of these can contribute to an alarm problem.
Fuse block problem?
Need a circuit diagram and testing equipment to diagnose the system.
Try Corvette Central for diagrams...they should have a schematic of the door and the parts.
I am not aware of ANY theft system stock on a C3 that prevented the engine from starting. My .02. Good Luck
There is also a pin switch (door ajar) in both door jams. They both have to function correctly or the alarm circuit is compromised. The drivers side door ajar switch connects directly to the alarm circuit.
There is a relay under the center console beneath the ash tray area. An issue with any and/or all of these can contribute to an alarm problem.
Fuse block problem?
Need a circuit diagram and testing equipment to diagnose the system.
Try Corvette Central for diagrams...they should have a schematic of the door and the parts.
I am not aware of ANY theft system stock on a C3 that prevented the engine from starting. My .02. Good Luck
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
My 1980 has a cylinder theft detection module inside the door perpendicular to the lock cylinder that senses whether the lock is being jimmied. There is another cam-like electronic pigtail at the base of the door lock cylinder that is activated by the key turning in the lock. Turn to the left <=== sets the alarm. Turn all the way right ===> deactivates the alarm. When setting the alarm, turn the key back as verticle as possible and gently remove the key from the lock.
There is also a pin switch (door ajar) in both door jams. They both have to function correctly or the alarm circuit is compromised. The drivers side door ajar switch connects directly to the alarm circuit.
There is a relay under the center console beneath the ash tray area. An issue with any and/or all of these can contribute to an alarm problem.
Fuse block problem?
Need a circuit diagram and testing equipment to diagnose the system.
Try Corvette Central for diagrams...they should have a schematic of the door and the parts.
I am not aware of ANY theft system stock on a C3 that prevented the engine from starting. My .02. Good Luck
There is also a pin switch (door ajar) in both door jams. They both have to function correctly or the alarm circuit is compromised. The drivers side door ajar switch connects directly to the alarm circuit.
There is a relay under the center console beneath the ash tray area. An issue with any and/or all of these can contribute to an alarm problem.
Fuse block problem?
Need a circuit diagram and testing equipment to diagnose the system.
Try Corvette Central for diagrams...they should have a schematic of the door and the parts.
I am not aware of ANY theft system stock on a C3 that prevented the engine from starting. My .02. Good Luck
Burning Brakes
Joined: Nov 2004
Posts: 1,193
Likes: 176
From: Hillsborough NC
I believe these are what you are looking for to get started.
Good luck.
http://corvetteforum.net/c3/tunedpor...l/index6.shtml
Good luck.
http://corvetteforum.net/c3/tunedpor...l/index6.shtml
Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
Hubs went to start my car, which is fairly new to me, and it appears that he activated an alarm system that I was not aware existed. I do not have a key hole on the front left fender, which I thought would show if it was a factory alarm.
Well, now the car won't start and every time we try to lock the car the alarm sounds.
Does anyone have a schematic for this alarm system, or know how to disable it so I can start my car?
Thanks! Mouse
Well, now the car won't start and every time we try to lock the car the alarm sounds.
Does anyone have a schematic for this alarm system, or know how to disable it so I can start my car?
Thanks! Mouse
You should be able to lock using interior lock, then close door.
Originally Posted by ...Roger...
As I said before the 78 alarm does not disable the starter.Unless it has run the battery down.
tiasd
tiasd
Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
I installed a newer alarm & did not disable factory alarm.
What year- you only list 89. I designed a kill switch for C4 up that will not allow someone to hotwire it & does did not disable factory alarm.
What year- you only list 89. I designed a kill switch for C4 up that will not allow someone to hotwire it & does did not disable factory alarm.
Pro
Joined: Sep 2007
Posts: 520
Likes: 0
I thought that with a factory alarm in a 78 Corvette with power door locks that a special relay was needed to disable the factory alarm.
The guys at Best Buy wanted to charge me for an extra relay to disable the factory alarm for the 89 Corvette alarm system.
The guys at Best Buy wanted to charge me for an extra relay to disable the factory alarm for the 89 Corvette alarm system.