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Topic: 1980 anti-theft alarm help!!!!!

in Forum: C3 Electrical

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Re: 1980 anti-theft alarm help!!!!! (10/20)
7/11/14 8:41am

CCasey
Former Member
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New Albany, OH - USA

Vette(s):
1980 Coupe / Snowcrest White / L48, 350 / Comp Cam / Edelbrock Heads / Cyclone Intake / Holley Carb / Holley Fuel Pump / Patriot Headers / Dual Exhaust / Magnaflow Mufflers / 1964 Coupe / Riverside Red / L76, 327, 365hp

Joined: 8/17/2010
Posts: 173

Not that this means anything, but I am the original owner of my 1980 and the alarm system never worked from the day I took delivery. I can't tell you how many times I took it back to the dealer. No luck. It was just one of the many things that were not correct on my car.

Quality was definitely NOT Job One for Corvette back in the late 70's / early 80's.

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Chuck

Re: 1980 anti-theft alarm help!!!!! (11/20)
7/11/14 9:37am

Redwoman
Former Member
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Bellingham, MA - USA

Vette(s):
1980 loaded red on red. 68,000 original miles. Second owner. Well documented with all original paperwork. NCRS Founders Award 9/27/14. NCRS Top Flight 10/12/14.

Joined: 6/23/2014
Posts: 175

Yipee!!!! I tried setting the alarm a different way and it worked. I turned the key CCW just far enough to set alarm but not lock the door. I open the door and the horn sounds like it should. So it has something to do with locking the door. When I read the owners manual it says the only way to arm and disarm the alarm is with the key. That the power lock or the button lock doesn't have anything to do with setting the alarm. But I had read where other members had said differently. This is the best forum!!

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Re: 1980 anti-theft alarm help!!!!! (12/20)
7/11/14 9:51am

Adams' Apple

Lifetime Member
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Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
Posts: 20201

Right....the only way to ARM/disarm the alarm system is with the door key. Now...you could lock the door from the inside with the knob/button, and then turn the door key ccw, and then you'll have both locked doors AND working alarm. My guess is that the switch is not properly set on the lock cylinder, or there is some other goofy problem with the switch.
Gettin closer, tho! You know now that the system does work....just gotta figure out why it's so temperamental. LOL

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Joel Adams
C3VR Lifetime Member #56
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Re: 1980 anti-theft alarm help!!!!! (13/20)
7/11/14 7:41pm

dskopp
Limited Member
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Oak Creek, WI - USA

Vette(s):
1981 Great White Shark. Red Interior, 350/190 hp. PS, PB (SS), A/C CC, T-Tops. Served three years in Active Duty Army, then Retired Air Force after 34 years! Badger State Vettes Car Club. 175,000 Original miles!! Now own a 1998 C-5!

Joined: 5/21/2008
Posts: 1965

My 1981 Door and alarm works when it wants too!! Just like my drivers window!! But the procedure to lock the doors is: Key in the lock outside of the car to arm the system!!

Dan da Man !! Hug

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(click to see a larger image)

Re: 1980 anti-theft alarm help!!!!! (14/20)
7/23/14 12:57pm

Do you know what position the switch should be on the back of the lock cylinder. Right now it is a six o'clock. When I repositioned it at 9 o'clock. The alarm set it self without the key. I shut the door don't set alarm or lock the doors manually or with the switch. If I open the doors, hood or tops the alarm goes off. When it is at 6 o'clock the alarm works properly has long as the key is still in the lock. So when turned CCW the alarm is setting. But it is just a hair difference between having the alarm set and removing the key. Just that hair difference is turning alarm off to be able to remove key. So close but yet so far. So it definitely an alignment issue. I have not been able to find what position the alarm wire should be on the back of the lock in any books. When I use the diagrams from the big name vendors they are not consistent. If I wasn't for the NCRS judging coming up I wouldn't care about the manual alarm working. The two eyes in the head alarm works just fine. LOL. The last time NCRS judged my car when it came to the operations section the only deduction was for the alarm. I am trying to obtain the NCRS Founders award. I have meet most of the criteria but the next operations check requires the alarm to operate properly.

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Re: 1980 anti-theft alarm help!!!!! (15/20)
7/24/14 8:53pm

druzac
Former Member
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Joined: 12/6/2012
Posts: 15

I did not think that the alarm system was hooked to the t-tops until 1982. I had an 81 back in the day and had two sets stolen by the thieves breaking the window to steal the tops (never opening the door to set off alarm).

Re: 1980 anti-theft alarm help!!!!! (16/20)
7/25/14 3:52am

See learn something new everyday! 1980 had alarm switches at the Ttops. If the plate where the ttop pin goes in is chrome on your car somebody could of changed them.

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Re: 1980 anti-theft alarm help!!!!! (17/20)
7/25/14 1:15pm

rraider1
Limited Member
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Woodland, WA - USA

Vette(s):
1977 T-Top,350,Auto Black Ruby Pearl,Steeroids R&P conversion

Joined: 10/14/2003
Posts: 1171

Here are pictures for 77 not sure what differences their are hope it helps

Re: 1980 anti-theft alarm help!!!!! (18/20)
7/25/14 1:22pm

Thank you. Next time I take door panel off I will try to reposition the alarm switch to the 3 o'clock position like in your picture. Let yon know what happens.

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Re: 1980 anti-theft alarm help!!!!! (19/20)
7/25/14 5:39pm

rraider1
Limited Member
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Woodland, WA - USA

Vette(s):
1977 T-Top,350,Auto Black Ruby Pearl,Steeroids R&P conversion

Joined: 10/14/2003
Posts: 1171

Remember keep it simple (KIS) if you have an OHM meter you can put it on the yellow and blue wire of the switch. you are looking for continuity on the switch when you turn it CCW and back to the center. then when you turn the key CW and back it should be open. I believe you have determined that the other components are working correctly.

The only thing this switch does is when it has continuity (closed) it has setup the ground circuit for the anti theft relay so that when any of the switches (both doors, hood and both t-top) will complete the ground circuit to energize it and the alarm sounds

Re: 1980 anti-theft alarm help!!!!! (20/20)
4/28/25 4:49pm

Flinky
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Vette(s):
Corvette 1981

Joined: 4/28/2025
Posts: 1

Hi,

Many years have passed since wince when this thread was created but I really hope you can still help me.

I have an 81 corvette with the anti theft system and replaced the door lock cilindinders and I am wondering what is the right position for the alarm switches on the colinders.
I guess you managed to solve the puzzle so…should I settle them at position 6 (wires pointing down) or 3 /9 (wires pointing forward) ?

what I noticed using a tester is the following:

Wires pointing down (6 o clock): when you insert the key (key is vertical) there is NO continuity. When you turn the key left to unlock (key is horizontal) THERE IS continuity.

Wires pointing forward: when you insert the key (key is vertical) THERE IS continuity. When you turn the key CW to unlock (key is horizontal) the is NO continuity.

( But when I turn the key vertical to take it off there is again continuity when it should not be until I turn it tothe other side to lock the door…?)

hope you can still help me!

fil

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