My car occasionally honks at me - 81SC alarm

schoward · 06-19-2006, 05:00 PM

81 SC with factory alarm system. Have key but have never tried it.

With alarm turned off (key off), I occasionally get a few random toots from the alarm horn. It does this sometimes when engine is running and no effect is noticed (module is supposed to cut power to fuel pump via relay when activated) - engine runs on just fine.

I discovered if I jiggle wires back behind master cylinder this stops it/starts it beeping again - in the area where a bunch disappear into the bulkhead (by drivers side hood strut).

so question - i suspect i have an intermittent power or ground - anyone know where power/ground wires from alarm go to to get their power or ground - Fuse block? somewhere else?

I have a spare alarm module but am unsure if that will solve anything if i have funny wire or two.

any troubleshooting advise welcome. bentley manual just tells you how to troubleshoot the actual alarm components.

Kevin Stewart · 06-19-2006, 08:55 PM

Do a search, most of us disconect them they are a piece of anyway, do a search, Kevin

slodave · slodave's Garage

I'm of no help. but the title is very funny - at least I thought so.

Brian Cameron · 06-19-2006, 10:12 PM

It just thinks you're cute.

schoward · 07-17-2006, 03:29 PM

ok it only took a year - but finally solved the problem with my randomly honking factory alarm on my 81SC.

I have heard of others having this problem, which basically causes the alarm horn to sound occasionally while the system is off. It can be quite embarassing and frustrating as there is no way to stop it. And it seems like no rhyme or reason. Sometimes movement or vibration triggers it or sometimes virtually nothing at all. Very wierd and annoying and VERY sensitive. At one point, the 'vibration' from my seat belt light buzzer triggered it.

Turns out the 2 wires that run from the alarm module to the key switch in the door goes through a 2-wire plug along the way to connect the wires coming in from the door key switch (probably to ease assembly of the car). It seems the plastic plug corroded/deteriorated so that the connection was sometimes 'lost' which I presume interrupted the expected resistance from the switch and caused the alarm module to think the key switch was disconnected or tampered with.

The 2 wires are a grey/brown combo and the plug is behind the master cylinder area (near the big plug which plugs in many of the other wires coming in from the door.

In any case, wanted to post this in case any SC owners experience this as it is really annoying and embarassing and something a shop would probably kill you on charges to find.

Oh - and afterward , I replaced my alarm key switch which had no key. Factory Alarm works perfectly. I love it when 25-year-old gizmos start coming back to life.

courtc2911 · 05-05-2008, 06:30 PM

I recently purchased an 82 SC (with a Code Alarm after market system) and am having problems with the siren(s). They just love to go off while I'm sitting at stop lights or am cruising down the freeway. I had a shop rip it out but all they could pull was the the brain and wiring. They couldn't find the siren(s), and they still go off!

Does anyone have any idea where I can locate these damn things? They must be removed and crushed before causing any more embarrassment!