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Isuzu Rodeo: My car alarm/horn went off this morning. This

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My car alarm/horn went off this morning. This happened a couple of years ago (2 a.m., 18 degrees; awesome!) when it was very cold (not so cold today, however). The horn goes off and won't quit. The Dealer (Isuzu) had no answer and showed me how to disconnect the horn in case it happened again. Key remote does not work to turn off the alarm/horn either. This morning, I unplugged the horn but the alarm kept going. It's a '98 Rodeo, manual trans, and rides really good, quiet. Should I take it somewhere and have the alarm disconnected or do you there's a bigger problem. I'm not afraid of anyone stealing it, so disconnecting the alarm is fine with me. Also, the only Isuzu shop in the area shut down. Thanks so much.
Thanks for asking your question on JustAnswer. My name is XXXXX XXXXX I'll do my best to answer your question.

There are several things you can do.

First you need to make sure your battery is good. You can have it tested at most any auto parts store. After you know it is good you should clean and tighten the battery cables. If they are not completely clean and tight enough that you can't turn them by hand then it can cause this problem.

Another thing to check (or have checked by a mechanic) is the hood switch. This is a known problem with these vehicles and can cause this type of problem. It could just need to be adjusted.

There isn't any way to truly disconnect this alarm system. It is built into the vehicles computer. There is an option for "tricking" it though. Under the drivers side kick panel there is a wire in a white plug. It is a yellow with a blue stripe. You simply have to splice another wire onto that so you can reach a good ground. Ground that wire permanently and it should not come on again.

This is something that should be able to be done by any good mechanic and you do not need the dealer for. A dealer would probably not perform this procedure anyway.

Please let me know if you need anything else.

Customer: replied 3 years ago.

Thank you so much for your reply.


Regarding the hood switch, that's the thing you pull to pop the hood, yes? If so, it does have a weird feel to it. I will check the battery per your instructions also.


Is there any particular reason this only happens when it's cold?

No it is not that switch. There will be a switch that goes down when the hood is down and comes up when the hood is up. There will be wires attached to it.

The most likely reason that it happens when it is cold is that there is more resistance to electrical current flow when the temperatures are cold. this is the reason that really cold weather is hard on batteries and other electrical components. This is why it is important to make sure all electrical connections are very clean and tight. And to be sure the battery is in good condition.
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