993James993

For no apparent reason the alarm horn started sounding on my 1990 C2. It is loud. The only way I can stop it is to disconnect the battery. As soon as I reconnect the battery it starts sounding again. The car starts and drives but the alarm continues to sound.

Any suggestions are very much appreciated.

s4magman

I feel for you. My '90 C2 had a funky alarm like yours. I replaced all door, hood, lid and glovebox switches. Haven't had a problem since. Could be a short somewhere. Or, it could be worse and your alarm unit is shot. Best of luck and let us know what you find.

darth

"Any suggestions are very much appreciated. " Search this forum for Big Green wire, alarm, etc.

993James993

Thanks guys.

I wonder if this is applicable?: http://www.pcarworkshop.com/images/8...0192geolab.pdf
(Thanks Geolab!) It was raining here today.

993James993

Hi Darth,

Is this the post you mean?:

In my case the radio is long gone and the green wire still has the factory connector on the end. I don't think it is shorting. Am I missing something?

jody stowitts

Turn key to unlock door to shut off. Or three quick locking turns. If no fix, maybe a relay stuck? Last resort pull fuse.

993James993

The key didn't turn it off. The fuse seems to be inside the alarm module which is mounted well behind the passenger side trunk hinge. There does not seem to be a fuse for this in the fuse block under the hood. I did pull fuse # 12 (central locking system) but that did not work.

Andy Roe

It could be a bad earth - try checking this?

darth

Hi Darth,

Is this the post you mean?:

Yep

"In my case the radio is long gone and the green wire still has the factory connector on the end. I don't think it is shorting. Am I missing something? "

My radio was long gone too. PO just cut it off and let it dangle. The inner conductor was either shorted to the outer wire shield and/or to the chassis of the car which was setting off the alarm.
If you've checked with an ohmmeter there is no connection from the center conductor of the wire to either the chassis and/or outer shield then you've eliminated this possibility. Try disconnecting door switches one at a time or if you're handy with a meter check that they're intact.

jzc28

Had the same problem with my '89 2 years ago that began during a rain storm. The alarm control unit was shorting out. Had to have it replaced.

993James993

Thanks everyone!

Jzc28, was your alarm sound constant or intermittent? Was the control unit readily available? Was is reasonably priced?

jody stowitts

Don't worry about radio green wire: If it were the problem you'd have a dead battery in 18 hrs. or less.

darth

In my situation if I remember correctly (i.e. its been about 10 years) I had no issues with the battery going dead unless I had left the alarm to sound but, I likely reset the alarm after no more than 12 hours as it was a daily driver and that was the maximum amount of time it was left unattended. I believe once the alarm is set it will remain armed until the condition is reset. In my case the green wire was an intermitten condition set off typically on windy days when somehow the wind would enter the cabin and disturb the wire dangling under the dash.

jody stowitts

You should have an Xtra auxillary fuse and/or relay to shut it all off. Look for an xtra fuse not shown on diagram on inside of fuse box lid.

jzc28

The alarm unit is a blue plastic box about the size of a cigarette pack located close to the firewall, passenger side, probably behind the glove box - access with the hood open. My mechanic had some difficulty fishing it out - it unplugs. As I recall after he dried out the circuitry, the horn stopped but in less than a month he had to resort to replacement. I don't remember the cost but it didn't seem too shocking. The original problem was intermittent. If the unit is the problem, recommend you seal the new or repaired one in a baggie. Also check the hood margin above the unit for a tight fit.