97C5driver

2 nights ago it started. I was at the movies and my neighbor calls me and says my alarm has been going off for 15 minutes! with 10 second breaks in between.

I disconnected the battery for the night (car was in the rain), then the next day reconeected. About 2 hours later, horn starts going off again.

Anyone have this problem before or know what it might be??


Thanks.

97C5driver

am i the only lucky guy thats had this problem

feb2910

horn membrane.

http://forums.corvetteforum.com/c5-t...s-morning.html

97C5driver

My horn doesn't hold a constant note when going off. Its the alarm setup (beeping horn & flashing lights).

Erics_02_z06

it happened to me a few times. I never found the problem. But from what I remember, that was before I found out my batery was leaking acid on my wires and such....so maybe you should check that?

Y2Kvert4me

One of your door switches is getting wet and shorting out.

On the C5, the door switch is located inside the door, on the latch mechanism. When the door is closed, the circuit is open. When a door is opened, the circuit is closed (completes a path to ground).

So all it takes is that one wire or switch to get wet and suddenly it shorts to ground, and the BCM then "thinks" a door has been opened, and the alarm sets.

Your first task is to figure out which door is causing it, then figure out how to keep the water out of the door and off the switch.

97C5driver

door switch huh, I will have to look into this further.

lucky131969

Which brings up another good check.......see if the BCM is wet....

97C5driver

good idea. i think ill go check it out right now.

rebelheart

Best check the wiring going to the doors also,they are prone to shorting.

hunterhicks

Your issue sounds a bit different than mine, but it may be worth saying. Every time I hit the lock button on the fob, my 01 would go into 'alarm mode' with horn blasting, lights flashing, etc. Very classy.

Yet another ground issue- the ground post on the passenger's front near the headlight on the frame grounds about 10 different wires. Make sure the 10mm nut is tight first, and then after that I just grab the giant bundle of ground wires and shake it. Yup, it's that scientific.

Also, if you have a (one) dim headlight, fog lights not working, or a turn signal that does not work, it's worth a shake.

TEXHAWK0

My alarm has never gone off by itself, but it has gone off when I open the drivers door and it should not have been set.
I am starting to suspect that my fob is not unlocking the doors and somehow leaving the alarm set.

It is still a mystery, but since I have started using the other fob that seems to trigger the locks better, it has not happened again. Time will tell. I had one fob that would unlock the driver door, but sometimes would not unlock the passenger door, or have to be pushed two or three times. The battery is good, so it may be that the button contacts just wear out where you have to push harder.

hunterhicks

This sounds like a door computer problem. (black box in the doors) Good 'ol corvette relays.

97C5driver

well i pulled the bcm today, no water or any trace. pulled the door panels, black boxes mounted on exterior of door shell dry.

So im not sure what to do next with this thing.

rebelheart

Pull the door "accordian covers back from the door to body and inspect those wires carefully.

jkapron

I had a similar problem w my 99, it was a result of cold weather, if you are in cold climate and your car gets cold enough the shroud around the horn will contract and for all intense purposes, begins to lay on the horn! I actually blew my horn this way a cold night out in flotida this past feb! still need to get horn fixed, not sure if its just a fuse.

drctrc

I had a similar problem with my 2000 convertible and I found the solution on this forum, but I have not seen my solution on your thread. My alarm would go off inadvertently, usually around 3 AM. Also, I would sometimes find my car with the trunklid open or the doors locked. It was almost like the key fob was pushing its own buttons, which is sort of what was happening. Through process of elimination, I figured out which key fob was causing the problem, removed the battery and threw it in the garbage. Never had the problem again. You may want to do a search on key fobs on this forum to find more info.

Carcass

Definitely sounds like a possible fob problem

97C5driver

ok so this problem had stopped for a few weeks and it just started again. water is not a part of this equation now as the car has been indoors for 2 weeks.

yesterday the locks were unlocking & lockin by themselves for about 10 seconds. it did this a few times when i was near the car. I removed the battery from my fob & the locks still triggered themselves.

I have the door panel off right now and was doing some inspecting.

I pulled the accordian back & the wires seem to be wrapped up fine in that purple wrap.

Im trying poke around in the engine bay for grounds but its like spaghetti in there.

Is the ground post near the pass. headlight under the frame?

Also, could it have something to do with the black boxes behind the door panels?

I just disconnected the passenger side actuator ( sometimes it would make a buzzing noise while the locks were unlocking/locking)

97C5driver

can the FOB transmit signals without the battery inserted????