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Help! Have i melted my alarm ?

English Guy

Well-known member
Joined
Dec 8, 2008
Messages
154
Location
Stevenage, Hertfordshire uk
Corvette
89 red coupe
Due to being half asleep I accidently connected a new battery the wrong way round for a couple of seconds at most and got few sparks flying before isolating battery:W.There are no blown fuses and everything works fine except there is a small power drain which stops when the blade fuse for the heater/blower is removed from the fuse box,also when the ignition is turned on the two horns blare out like the alarm has been set off and only stops if ignition turned off.
I can't believe I made such a stoopid mistake :rotfl and any ideas on this would really be a great help. many thanks guys.
 
Have you disconnected the battery at all after the horns started sounding?...if not, open the drivers door with the key and it should stop the horns. The security light should be flashing before arming it with the lock button and be solidly lit when the system is armed.

Hope that helps you....
 
Have you disconnected the battery at all after the horns started sounding?...if not, open the drivers door with the key and it should stop the horns. The security light should be flashing before arming it with the lock button and be solidly lit when the system is armed.

Hope that helps you....

Hi djsroknrol, I have disconnected the battery since but will try what you suggest in the morning anyway as it's got to be worth a try at least,many thanks for your time.
 
Hi djsroknrol, I have disconnected the battery since but will try what you suggest in the morning anyway as it's got to be worth a try at least,many thanks for your time.

Yes, try turning the alarm off with the key in the door...that may reset it to its normal cycle. I have had mine go off by exiting the car after having locked the door, let it close, then re-opened to exit and the alarm goes off...key in the door lock was the only way to reset it.

As long as the ign key was not turned ON while the battery was reversed,. and it was just for a second, it should be OK.
 
Yes, try turning the alarm off with the key in the door...that may reset it to its normal cycle. I have had mine go off by exiting the car after having locked the door, let it close, then re-opened to exit and the alarm goes off...key in the door lock was the only way to reset it.

As long as the ign key was not turned ON while the battery was reversed,. and it was just for a second, it should be OK.
Hi boomdriver many thanx for the info, I will try first thing in the morning and post any progress made .btw I cannot be sure the ign was off 100%, if it was on could this have fried something(no smoke or burning smell evident) expensive?
 
Hi boomdriver many thanx for the info, I will try first thing in the morning and post any progress made .btw I cannot be sure the ign was off 100%, if it was on could this have fried something(no smoke or burning smell evident) expensive?

Its a computer...and most of its systems run on 3-9 volts and mili-amps.
 
Its a computer...and most of its systems run on 3-9 volts and mili-amps.
sounds like i'm in trouble as nothing seems to stop the horns except taking the THEFT fuse out (not the heater/blower fuse i quoted yesterday) or unplug horn connectors .When i turn on ignition (horns unplugged and theft fuse plugged in) the security light comes on solid for 2/3 seconds then goes out ,car still starts no problem because vats bypassed by previous owner.:confused
 
Did you try unlocking both doors from the outside with the round key?
 
Then it sounds like either the horn relay or the anti-theft module is stuck in the closed position....
Good input. When the fuse is in, do the horns sound continuously or do they pulse at a 50 Hz rate like the alarm has tripped. If they pulse, the Relay is good and the Theft Deterrent Module is also not stuck closed. The Theft Deterrent Module could still be bad, but it isn't stuck closed as this would sound the horns continuously. We need to find out if the OP has tried to disarm the anti theft system using both doors and if the horns sound continuously.
 
Good input. When the fuse is in, do the horns sound continuously or do they pulse at a 50 Hz rate like the alarm has tripped. If they pulse, the Relay is good and the Theft Deterrent Module is also not stuck closed. The Theft Deterrent Module could still be bad, but it isn't stuck closed as this would sound the horns continuously. We need to find out if the OP has tried to disarm the anti theft system using both doors and if the horns sound continuously.

Hi, when i put the fuse in the horns sound continuosly:confused
 
Hi, when i put the fuse in the horns sound continuosly:confused
OK Brian, then I'd remove the Horn Relay and check to see if there is a constant ground (earth) from the Theft Deterrent Module. It will be the black wire to the relay. If it is constant ground, I'd have say you most likely smoked your Theft Deterrent Module. I have a spare that should be the same as your '89, if you'd like to try it to verify your problem. But first remove the DIC to get to the Horn Relay and verify what you have from the module.
 
OK Brian, then I'd remove the Horn Relay and check to see if there is a constant ground (earth) from the Theft Deterrent Module. It will be the black wire to the relay. If it is constant ground, I'd have say you most likely smoked your Theft Deterrent Module. I have a spare that should be the same as your '89, if you'd like to try it to verify your problem. But first remove the DIC to get to the Horn Relay and verify what you have from the module.

Morning Ray could you please tell me what the DIC is? How do i get to it and what the anti theft module looks like?:) I hope i hav'ent ruined the module but a loan of your spare would be a godsend. Btw how did you end up with a spare module?Many thanks for your time on this and the offer with the module:):):).
 
Morning Ray could you please tell me what the DIC is? How do i get to it and what the anti theft module looks like?:) I hope i hav'ent ruined the module but a loan of your spare would be a godsend. Btw how did you end up with a spare module?Many thanks for your time on this and the offer with the module:):):).
Brian, The DIC is the Driver Information Center, located to the right of the Digital Cluster Data Selector Switches. It has the warning and information lamps. Behind this panel is the Multi-Use Center where the Horn Relay is located. The center trim panel needs to come off first then the DIC. The Multi-Use Center looks like this:
multi-use.jpg
The module is about 4 inches square and is a bit difficult to find behind the passenger dash, but let's jump off that bridge when we come to it. Let's get to the Horn Relay and make some checks first. I have many spares that I brought to the UK with me back in 1990. The UTDS Module is one of them. Did you know that Keith Beschi, proprietor of EUROVETTES is local to you? He can help with this as well. I'm happy to help, don't get me wrong. I work Wednesday through Saturday just up the A1 near Huntingdon and could meet you if you need my help in person. Could do it before work on Saturdays. Let me know and I could have my tools.
 
DIC is center console dash, where the SES light is, and some other warning / status lights are.

RQ beat me to post...

(looks like he could beat me to your house too)
 
Brian, The DIC is the Driver Information Center, located to the right of the Digital Cluster Data Selector Switches. It has the warning and information lamps. Behind this panel is the Multi-Use Center where the Horn Relay is located. The center trim panel needs to come off first then the DIC. The Multi-Use Center looks like this:
View attachment 2467
The module is about 4 inches square and is a bit difficult to find behind the passenger dash, but let's jump off that bridge when we come to it. Let's get to the Horn Relay and make some checks first. I have many spares that I brought to the UK with me back in 1990. The UTDS Module is one of them. Did you know that Keith Beschi, proprietor of EUROVETTES is local to you? He can help with this as well. I'm happy to help, don't get me wrong. I work Wednesday through Saturday just up the A1 near Huntingdon and could meet you if you need my help in person. Could do it before work on Saturdays. Let me know and I could have my tools.

Hi Ray I have got to the relay no problem and it doesn't seem to be jammed/damaged in any way, need to have a closer look in the morning when it's light. As for Keith Beschi I have known him for several years and he lives five minutes drive from me. A great bloke to know, especially if you have a corvette:L I will e-mail him at the weekend. The corvette is off the road at present so cannot take up your kind offer of meeting up at the moment. Thanks again for this:)
 
Hi Ray I have got to the relay no problem and it doesn't seem to be jammed/damaged in any way, need to have a closer look in the morning when it's light. As for Keith Beschi I have known him for several years and he lives five minutes drive from me. A great bloke to know, especially if you have a corvette:L I will e-mail him at the weekend. The corvette is off the road at present so cannot take up your kind offer of meeting up at the moment. Thanks again for this:)
You now need to unplug the relay and use an ohm meter to measure resistance between the black wire and a good earth point. If you show 0 ohms, this is what is keeping the horn relay energized and the horn blowing constantly. This earth is most likely coming from the Theft Module based on your initial post. If Oz or another kind sole can't get you a good photo of the Theft Module and its location, I'll post them when I get home on Sunday. It could also be a shorted horn button connection, but based on your initial post, a smoked UTDS Module is more likely.
 
You now need to unplug the relay and use an ohm meter to measure resistance between the black wire and a good earth point. If you show 0 ohms, this is what is keeping the horn relay energized and the horn blowing constantly. This earth is most likely coming from the Theft Module based on your initial post. If Oz or another kind sole can't get you a good photo of the Theft Module and its location, I'll post them when I get home on Sunday. It could also be a shorted horn button connection, but based on your initial post, a smoked UTDS Module is more likely.

Hi, i have tested the connector pin with the 2 black wires going into it(3 pin relay plug) with meter and am getting reading of 7 ohms,only getting reading with ignition off which sounds right and have noticed security light continually flashing until I close doors or put key in ignition

Bri
 

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