Had a new one show up today...
1992 LT1/auto coupe.

Run the car in the driveway, let her come up to temp... no issues.
Start driving, and go about 2 miles and the 'chime' begins to ring.

No 'check engine' light... no lights on the panel at all.
I'm wearing my seatbelt, and even tho that light isn't lit, I reach across and buckle the passengers belt too.
No change.

No indication anywhere on the dash that anything is wrong, but still the chime rings.

Anyone seen this one before?

 

Check the door switches and make sure they are closing. They may be marginal and need to be adjusted. Pull out the stem and close door.

On a wild thought, there may be something weird happening with the lock cylinder with a contact while you're driving.

I was also thinking about the headlight switch but that is quite a stretch.

 

There is an idea.
I'll try again tomorrow and if the chime starts ringing, I'll try opening and then closing my door.
I'm in the habit of not slamming my doors, so...

This is very strange because there is no indication anywhere on any of the dash lights that anything is wrong.

Would a bad sensor, such as oil or water temp give this sort of alarm?

 

I don’t think so.

Without checking the FSM, there are only a few things the chimes respond to. Doors, lights, key in cylinder and seatbelt.

 

I have the FSM for this car, but it has not been helpful thus far.

Got to thinking about that door switch...
If that was the culprit, I'd also be getting a 'door ajar' light, and I'm not.
Same for the seatbelt. No light.

That leaves the key and the light switch.
Taking it over to my local shop this morning to see if they have any ideas.

 

Was your turn signal on for more than a mile? That will also set the chime off...

After the chime starts, does anything stop it, or does it keep chiming until you turn the car off?

Exactly right, you'd be getting the Door Ajar warning light if it was sensing the door was open, and same for the seat belt.

Does your door ajar and seat belt warning lights illuminate during the bulb check when you turn the ignition on? A burnt bulb can be hiding the cause of the problem...

Nick

 

1 Turn signal was off the entire time.

2 Once the chime starts, only shutting off the motor will make it stop. Re-start the motor and begin driving and the chime sounds again in 2 to 3 miles.

3 Something I tried... When the chime started, I popped the drivers door and the 'door ajar' light came on. Close the door and the light went off... but the chime continued.

4 I did not notice the seat belt light (need to check that one), but yes, the 'door ajar' light does illuminate when a door is open.

I took the car to my local shop and took their top tech for a ride. Everything happened as stated and I showed him all of the things I'd tried. He was as stumped as I was, but I left the car with him for the time being. He dropped me off at home and drove away, and I'm guessing the chime drove him nuts for the next 4 miles back to his shop.

 

The bulb check is important. It may that the seat belt switch is defective, and a burnt out bulb would make it hard to determine what is causing the chime...

You could have a malfunctioning CCM. A short in the wiring to the various devices which control the chime is unlikely because the chime is not immediate; it takes a couple of miles of driving to set it off...

The TSB has a diagnostic chart for this problem. It is attached below.



Nick

 

The Tone Generator has 3 chime rates.
The chime rates are Slow, Medium and Fast.

What rate is chime tone when the problem occurs?

Fasten Seat Belt and Turn Signal Warning = Slow
Key in Ignition Warning = Medium
Lights On Warning = Fastest

 

The chime tone was at the slow rate...
(think turn signal) so...

The mystery has been solved!

With some of the clues here in this thread, and a little outside detective work, we discovered the cause.

I have been in the process of changing out all of the exterior, and interior lighting on this car to LED's.
Part of that process including swapping out the 20 year old turn signal flasher with an 'electronic LED compatible' flasher.

The flasher ended up being the culprit.

Because it is electronic, you really cannot hear a click, click, click like you could with the OEM flasher, especially with it being buried up under the dash and the exhaust rumbling.
That flasher was always 'on' according to the ECM. Drive a couple of miles, and the 'grandpa, your turn signal is on' alarm sounded.

Since we had checked everything else, the flasher was narrowed down as the suspect.
Now, the 1992 OEM flasher would not cycle the turn signals. They would light, but would not flash.

The solution, was to remove the 'electronic' flasher and use a modern day GM flasher.

Apparently, because so many modern day GM cars have LED lighting, the newer flashers have taken this into account, unlike a flasher from 1992.
Todays flashers are made to accommodate LED's and incandescents, so the solution was really that simple.

Live and learn.

 

Ohhhhhh yes, the flasher, I did forget about that one for it almost never comes up.

Nice work in getting it fixed and figuring it out.

Action and reaction. Make a change and might need to compensate or redesign.

 

Absolutely.
The compensation (the electronic flasher) ended up being the ultimate problem.

The solution... was to use a modern GM part that takes new-era product into consideration.
Sometimes, it's just that simple... though discovering the fact can take a bit of time, sweat, and detective work.

 

So what flasher did you use? I am having the same problem right now. So glad I got to this topic to find the solution. Thanks.

 

We may never know. This thread is twelve years old and the OP hasn’t been active on the Forum for seven years. Please consider asking your question in a new post.