1986 Theft deterrent system
Thread Starter
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1986 Theft deterrent system
I just bought a 1986 vette and someone has already hacked a lot of the wires up and I'm trying to get things back. The theft deterrent system is sketchy at best. It seems to work but will not disable when the key is inserted in the door. I had to replace the door locks because it only came with an ignition key and seems to have a bypass in that because the key doesn't have a chip in it. When I open the door and the horn goes off I jumper the wires that go to the door lock and it goes off. But I would like to get rid of it altogether someone can point me in the right direction.
Team Owner
Joined: Jan 2003
Posts: 20,304
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From: Summerland B.C. Canada
If you want to kill the horn honk, cut the wire from theft deterrent controller, at horn relay. The horn relay is behind info center, above radio.
There are 2 black wires going into relay, one is from steering wheel switch, the other from controller. You have a 50% chance of cutting the correct wire the first time.
Here is some info and electrical schematics from my 86 service manual.
http://members.shaw.ca/dankai/Vats%20Electrical.pdf
There are 2 black wires going into relay, one is from steering wheel switch, the other from controller. You have a 50% chance of cutting the correct wire the first time.
Here is some info and electrical schematics from my 86 service manual.
http://members.shaw.ca/dankai/Vats%20Electrical.pdf
Safety Car
Joined: Sep 2004
Posts: 3,953
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From: Mission Viejo CA
If you cut the wire at the horn relay, the horn won't blow, but you'll still get a "no-start" if the alarm circuit activates for some unknown reason, but it won't be apparent that it's your alarm that's causing the "no-start".
If you want to disable the alarm function, just pull the plug at the alarm module. There will be no more false alarms, no more "no-starts", and everything will work normally (except the alarm, of course).
Last edited by Hot Rod Roy; Dec 8, 2014 at 01:12 AM.
Safety Car
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From: Minneapolis Mn
Thread Starter
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Joined: Dec 2014
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If you don't have a chip in the key, you must not have the VATS system.
If you cut the wire at the horn relay, the horn won't blow, but you'll still get a "no-start" if the alarm circuit activates for some unknown reason, but it won't be apparent that it's your alarm that's causing the "no-start".
If you want to disable the alarm function, just pull the plug at the alarm module. There will be no more false alarms, no more "no-starts", and everything will work normally (except the alarm, of course).
If you cut the wire at the horn relay, the horn won't blow, but you'll still get a "no-start" if the alarm circuit activates for some unknown reason, but it won't be apparent that it's your alarm that's causing the "no-start".
If you want to disable the alarm function, just pull the plug at the alarm module. There will be no more false alarms, no more "no-starts", and everything will work normally (except the alarm, of course).
Le Mans Master
Joined: Aug 2007
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From: WV
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Team Owner
Joined: Jan 2003
Posts: 20,304
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From: Summerland B.C. Canada
If you cut the wire at the horn relay, the horn won't blow, but you'll still get a "no-start" if the alarm circuit activates for some unknown reason, but it won't be apparent that it's your alarm that's causing the "no-start".
If you want to disable the alarm function, just pull the plug at the alarm module. There will be no more false alarms, no more "no-starts", and everything will work normally (except the alarm, of course).
Also, you have to stand on your head to get at theft deterrent controller, so cutting wire at relay, seems to be the least painful method.
Race Director
Joined: Apr 2002
Posts: 10,036
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From: Anaheim CA
The VATS module is mounted on the front of the dash frame behind the "bread loaf". It is more or less in the upper center part of this picture:
The TDS (Theft Deterrent System) module -- the one that honks the horn -- looks the same as the VATS module but is taped to the wiring harness behind the dash frame and also behind the VATS module.
The TDS (Theft Deterrent System) module -- the one that honks the horn -- looks the same as the VATS module but is taped to the wiring harness behind the dash frame and also behind the VATS module.
Thread Starter
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Well I'm finally getting things back together and I unplugged the theft deterrent module and did the starter relay bypass and now the horn doesn't work but I can hear the horn relay clicking. If anyone has an idea it would be appreciated
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
Here's the wiring diagram for the horns from the '86 shop manual:
The horn button and TDS are in parallel, so the horns should still work if the TDS is disconnected.
Speaking of disconnected, are the horns disconnected?
The horn button and TDS are in parallel, so the horns should still work if the TDS is disconnected.
Speaking of disconnected, are the horns disconnected?
Thread Starter
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the horns are connected, that's how I found out it was malfunctioning. but next warm day I'm going to check and see if I'm getting power to it and start backtracking things. I just purchased a manual off e-bay and hopefully will have it in a week or so.