# 1999 Sentra, Battery died, alarm won't stop



## TrentB (Mar 27, 2011)

We have a 1999 Nissan Sentra that we've had for 4 and half years. Friday morning I left the lights on so the battery died. When I tried to jump the car yesterday, an alarm goes off and I can't get the engine to start.

Funny thing is, we didn't even know the car had an alarm. We've never used it and it's never gone off. The car is manual EVERYTHING. I don't believe we ever got an alarm remote from the person we bought it off of. So I'm at a bit of a loss.

I did a lot of research trying to figure it out and according to the owner's manual, it seems like if it's a factory installed alarm, then I should be able to turn the alarm off by unlocking the driver's side door with the key. But that doesn't work.

I read you might need to lock, unlock a few times in succession to disarm the alarm. No dice.

So if it's an after market alarm (and why would anyone install one of those on this car, but whatever) there should be a valet button but I don't see one. I've crawled upside down to look under the dashboard and nothing jumps out at me.

So I can't even tell if it's factory or after market. My guess is factory. There is an LED light on the lower left side of the steering wheel that blinks when the alarm goes off, next to the instrument brightness switch. I've never noticed it before now, but it certainly looks like it came with the car.

Given all of that, does anyone have a suggestion on how I can disarm this alarm so I can start the car? I'm really dreading having to tow the car to a garage or dealer and dumping a ton of money into getting this sorted out.

Any help is appreciated


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## Peanut (Mar 23, 2011)

You can probably get the alarm to shut off by completely removing the battery. There may not be enough voltage to turn the engine over, but there's enough to let the siren wail. After that, look around under the hood and find the siren or horn that is being set off by the alarm. You're gonna have to start tracing wires until you stumble across the brain of the alarm system. 

That being said, *don't start cutting wires and such just yet*. You need to make sure that the alarm is indeed aftermarket, and google the Model number of that unit. See if it has an option for a starter interrupt (A feature that doesn't allow starting of the car in the event of attempted theft.) If that's not an option, start tracing all the wiring from it and see what all it is connected to. If it's just lamp wires (Opening the door turns on the interior lights, which could send a signal to the alarm) and other trivial things, you should be safe removing the system yourself. 

If you're not comfortable pulling this thing out, FIND A LOCAL CAR AUDIO SHOP AND PAY THEM TO DO IT!!! If that system seems to be hooked up to everything in sight, there's no telling what you could inadvertently disable permanently by hacking the system out of there. Brains first, brawn second.

When I was doing car alarm installs, I hid the brain for the system all over the place, but never anywhere easily accessible. If it was done at a big box store, it might be easy to find, if a small shop guy like myself did it, it could be ANYWHERE. I also typically put the valet button in the glove box, unless it was requested otherwise. Didn't notice it in there did ya?

Any more questions, just let me know... You're not near Nashville by chance, are you?


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## TrentB (Mar 27, 2011)

*Thanks for the reply*

Peanut,

That's exactly what I ended up doing last night. After crawling under the dashboard for an 8th time looking for the valet button and searching everywhere for a fuse that might disable the alarm, I noticed that the speaker in the engine had a wire that went through a conspicuous hole into the dashboard.

I was able to follow that until I found the black box brain. I had to take off the lower dashboard panel and it was a bit of a trick to squeeze it out of the spot it was in, but once I got it out, I just disconnected the connector that all of the wires went through (sort of looked like a hard drive IDE connector) and the car started. Hallelujah!

All of the wires disconnected gracefully except for the one to the LED light in the dashboard, so I only had to cut that one. The rest of the wires got stuffed back into the dashboard.

The brain had no brand or model name, just a S/N. And I did look in the glove box for the valet button. In the end, I looked EVERYWHERE. I still have no idea where it is. But now I don't care.

For anyone else who might find their way to this thread, one proposed solution that I came across was to unhook the negative connector to the car battery, then put the key in the ignition, turn it to on and leave it there while you reconnect the battery. Can't say if it works because the nut on my battery was too corroded for me to take off. But the guy referred to it as THE way to get around the alarm.

All the best to anyone who has to deal with this issue. It's certainly a huge pain in the ass.


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## Peanut (Mar 23, 2011)

Sad I wasn't faster to the punch!  On the upside, it's good to hear you got it sorted out!! :woowoo:


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