1997 LeSabre Theft Deterrent Problems - Trunk

[scottndsky]

Greetings Forum Members,

My first post starts here...

I recently purchased a 1997 Buick LeSabre Limited with only 36k miles. However, since day one the factory "Theft Deterrent System" has been going off at random times for no apparent reason, causing a scene in my driveway as the horn blares away.

After reading about the system in the Owners Manual I went around the car and systematically checked to make sure that all of the doors would properly trigger the alarm when opened. The doors worked fine, however I cannot seem to trigger the alarm by opening the trunk lid. The manual clearly says the system includes truck protection, but I cannot fake it out to verify that it’s working correctly. Here's the little test procedure I'm following...

1 - Open the trunk lid.
2 - Hold closed the switch attached to locking mechanism, just to the left of the trunk release solenoid.
3 - Active the alarm with the remote key-less entry FOB.
4 - Wait for the Security light on the dash to go out.
5 - Release the switch simulating the trunk opening without the key.

The result: Nothing happens... The alarm never goes off. Yet, the light in the trunk goes on and off as I press and release this switch.

I feel that these two symptoms are related, that the alarm keeps going off at random times because something is not right with the trunk circuit.

Any thoughts or advice would be greatly appreciated!

Regards,
Scott

[brcidd]

First- my schematics show the trunk light switch on a separate circuit from the tamper switch-- the light switch has a blk/wht and an org/blk wire to it-- whereas the trunk tamper switch has a blk and a lt blu wire to it

Rear Compartment Lid Latch Switch In the center of the rear compartment, on the rear compartment latch


Rear Compartment Lid Tamper Switch
On the center rear of the rear compartment lid, on the rear compartment lid lock cylinder


I had a Riviera act the same way once-Horn would go off at intermittent times- even while driving- (lights also flashed- because it was the alarm going off)-- Anyway, it was the tamper switch inside the driver's door- so I snipped that wire for good-- problem solved

[Scrapper]

do you have trunk pull down? if so my moms 92 it was the top latch? they told her it was the moter in it but not i put moter on still would not latch it was the top switch.

[scottndsky]

Originally Posted by scrapper1

do you have trunk pull down? if so my moms 92 it was the top latch? they told her it was the moter in it but not i put moter on still would not latch it was the top switch.

No, there is no trunk pull down.

[scottndsky]

Originally Posted by brcidd

First- my schematics show the trunk light switch on a separate circuit from the tamper switch-- the light switch has a blk/wht and an org/blk wire to it-- whereas the trunk tamper switch has a blk and a lt blu wire to it

Rear Compartment Lid Latch Switch In the center of the rear compartment, on the rear compartment latch

Rear Compartment Lid Tamper Switch
On the center rear of the rear compartment lid, on the rear compartment lid lock cylinder

Agreed! There are actually three sets of wires all running within the truck lid that connect to different locations on the lid latch.

1 - Trunk Light Switch - this strikes the big square ring at the bottom of the trunk when the trunk is closed, the same ring the latch grabs when it closes.

2 - Trunk Tamper Switch - concealed behind the lock core.

3 - The solenoid for the remote trunk release (activated by the FOB or button on the dash)

Can you confirm that the Truck Light Switch *only* operates the light? My assumption is that this is also tied to the alarm system somehow. What leads me to believe this is the following statement in the Owners Manual:

"If a door or the trunk is opened without the key or Remote Keyless Entry transmitter, the alarm will go off. It will also go off if the trunk lock is damaged."

It seems to me that the only way the Alarm system would know if the truck was opened without the key is by way of the Trunk Light Switch. Without inserting a key into the lock core, if I pried the truck open with a crowbar I can imagine that light switch opening and setting off the alarm. Can you please confirm my assumption about this switch?

Thanks again,
Scott

[Scrapper]

ok did you check all the fuses thats got the cover over them by the fire wall? you may have a blown fuse on a seperate thing that blows and might cause that. it's just a thought and there big fuses.

[scottndsky]

Originally Posted by scrapper1

ok did you check all the fuses thats got the cover over them by the fire wall? you may have a blown fuse on a seperate thing that blows and might cause that. it's just a thought and there big fuses.

I can't check the fuses at this moment as the car with the dealer we purchased it from. Unfortunately, they haven't been able to find a problem with the car. I can only assume the fuses is one of the things they've checked, but who knows... They claim the alarm hasn't gone off since they've had it, but when they lock up at night who knows what happens.

Thanks,
Scott

[Scrapper]

maybe you should go in there for awhile and see if it go's off if you have the time. maybe they take cable off before they close? let me tell you they cant keep you away from your car while it's in there you just got to stand back a little. good luck.

[scottndsky]

Can someone please confirm my assumptions about the Trunk Light Switch? Is it connected to the alarm system, or does it simply switch the trunk light?

Thanks,
Scott

[brcidd]

There are two separate switches- the trunk light is all by itself- the tamper switch is all by itself- That is why there are different wire colors- because they are on different circuits- Did you not see the two switches?? One is on the trunk lid-- the other is on the latch as per the service manual- and what I shared with you already..The trunk light has absolutely nothing to do with the tamper switch- you can flip that light switch all you want- it won't set off the tamper alarm...try holding the tamper switch until the security light goes off- if you want to test the tamper alarm for the trunk...

[stripe]

My guess

The tamper switch is behind the lock so that if the lock was damaged it breaks the circuit and starts the alarm.

The connections may now have corrodid a bit and now are intermitent.

Solution: take the assembly off and clean it.

I think they run on a positive current (when broken it starts the alarm)

Guessing
Stripe

[Scrapper]

no light has nothing to do with your alarm going off..

[scottndsky]

Thanks guys!

Ok, got it! The light switch has nothing to do with the alarm. The Owners Manual is misleading regarding the operation then. It leads you to believe that the truck can activate the alarm under two conditions:

1 - the trunk is opened without the key or Remote Keyless Entry transmitter.
2 - if the trunk lock is damaged.

That's why I thought the light switch might also be involved. If someone pried the truck open with a crowbar I have doubts that the tamper switch would activate the alarm. The light switch is in a position to detect if the truck physically opens (by crowbar or anything else), so it seemed reasonable that it could be linked to the alarm somehow.

Thanks for clarifying!

Scott

[scottndsky]

Update...

Today I disconnected both switches at the trunk latch - the light switch and the tamper switch - and the alarmed continued to go off today. Now I'm thinking the problem has nothing to do with the trunk.

Does anyone have any other ideas as to why the alarm continues to goes off spontaneously?

Thanks,
Scott

[Mickey#1]

Try taking the batteries out of the remotes, let's rule them out first.