So before I go tearing into my column.
Thought I'd ask for some advice.
On my early build 77 model I recently noticed that my key left in the ignition alarm was not working. Strange I thought. It always had before. So doing a brief check. I found that if I pushed the key inwards lightly. the alarm would indeed sound. Take my finger off the end of the key. and it goes off.
Now of course this isn't the end of the world. But locking one's keys in the car can be a pain.
So, something is worn. or simply needs an adjustment.
And before I go tearing in and possibly break some delicate one year only parts. Thought I would see if anyone else has had this issue.

 

I would guess that you are having a problem with this part in the steering column. I had a similar issue on my '72. The key has to contact both of these leads to cause the buzzer to sound. So if the problem is not with the buzzer itself, it might be this part. Do you happen to have two ignition keys? Have you tried your extra key per chance?

 

Thanks for the photo, still not certain if it can be adjusted or needs replacement.
Anyway, dug out the spare keys from my secret hiding place.

As you can see, the one on the top has been used for 45 years. Just a bit of wear on it compared to my spares.
so , I gave it a go. Both spare keys same result. Slightly better than worn key as in if I press lightly on the end of the key, pressing it inwards the alarm beep goes off and stays on when I release it. But turn ignition on, then off and key alarm does not go off until pressing key inwards lightly.
Seems something is just a touch out of adjustment.
Haven't been inside that column in years. just don't remember that switch nor has it ever given me trouble till now. Car is getting old. But I still take pride in the fact everything works as it should.
So I gotta get this straightened out.

 

My 77 does exactly what you described in my tilt-tele column. Not the end of the world but would love to have it working again too.
Also tried new keys hoping they would activate it but no luck. Sometimes its on for a second or 2 but that's it.
I just dont feel comfortable going any deeper into the column beyond the steering wheel removable.
Worked years ago, worn over time I guess. Headlight and seat belt reminder works, would love
to have all 3. Good luck.

 

I also have a 77 column. My key buzzer switch is also flaky.

As I recall it, the switch pictured above just drops into a slot where a plastic nub on the switch comes into contact with a tab that pops out of the lock cylinder when the key is in the lock. The tab pushing the plastic nub presses the contacts inside together, closing the circuit.

The two long metal arms in the switch are the connection back to the wiring harness.

I had this all apart a year ago and tried to fiddle with it. There’s no adjustment- it just drops in and it either works or doesn’t. The things I could think of to try would be looking at the body of the switch to make sure it isn’t worn down, and looking at the nub in the lock cylinder for the same. Unfortunately for me, both my switch and lock cylinder were replaced so that’s not my problem.

Good luck. If you find an actual fix, post it. I’d love to know how to make mine reliable.

 

My 73 had the same issue with the key left in Alarm not working. I replaced the turn signal assembly and realized that the little leaf switch was even further down in the steering column. You are talking major heart surgery, and I decided that it would not be smart for me to start messing with the ignition switch and it’s associated parts. I am one of those old guys who knows all to well my capabilities!

 

Well, I'll continue to look into this. And keep everyone informed. Sounds like my car isn't the only one with this issue.

 

OK. so consulting the factory service manual it seems the little switch can be adjusted. So, apart came my column.



So, disconnect battery, pull horn button and start pulling wheel.

Note these scribe marks on the shaft and wheel hub.

Put the star bolt back in after removing nut and give it a smack or 2 with a hammer. Hub comes right off. Or you can use a steering wheel puller. I had mine off quicker than I could find my puller.


Next carefully remove this clip retainer. Mine crumbled. lower photo shows it super glued back together.
Anyone have a part number or source for a new clip retainer?
once off slide clip up and off.

Remove the steel snow flake looking plate then then contact plate.

Remove 4 way flasher **** and little arm to the signal lever.

And then you'll be looking at this. Remove 3 screws retaining the signal switch. pull it up out of the way. Wiring won't let you go far but thats OK.
Factory says make a hook tool and pull key alarm switch out by the retaining clip.

looking at the switch, retaining clip is on bottom left.


Hard to photograph and actually do the job. but here's the switch with the hook tool where it's needed to pull switch.
Ignition key must be in the run position and simply pull straight out.

key in run. Keep key in run till finished.

Now this is fun to photograph so sorry if it isn't super clear.
but looking through the "door" in the switch you can see the contacts top left of door. the gap is supposed to be set no more than .030 and greater than .025 according to Chevrolet. Mine was clearly over .030 so I figured I had this licked. The service manual shows how to check it but not how to adjust it. So I pulled the contacts out of the plastic housing.

Looks like this pulled apart. note on the upper contact on the far left of it the part bent up. the tip of this contacts the inside of lower, left contact. see in above photo that the bend is not quite at 90 degrees, maybe more like 80 degrees.

bending that contact, the part on the far left closer to a 90 degree bend will close the gap in the switch once assembled.

That gap .
Got it within spec.
Then reassemble in reverse of disassemble. getting that switch in with the spring clip is fun. but doable.
Result.
With a new key the alarm now works most of the time. Sometimes it doesn't. then a light push inwards on lock cylinder sets off alarm and it stays on.
Conclusion:
My issue is caused by wear / adjustment in the key alarm switch, wear of the key itself as the new key stays deeper in the switch. huge wear on my old key. And unfortunately, also wear in my lock cylinder which has a good 1/8th inch of end play. maybe a bit more.
So. I made it better adjusting the switch and replacing the key with one not worn. but it looks like a new lock cylinder will also be needed.
And that plastic clip retainer!

 

Great write up, thank you. Good to see my recollections confirmed.

I had no idea there was an adjustment procedure or spec for the switch contacts. It’s entirely possible my new Chinesium switch came with the contacts too far apart. I’ll have to take it back apart and measure them.

The plastic part that crumbled on your column is the Turn Signal Cancelling Cam Plastic Retainer, GM part number 7808385. Hope that helps.

Again, thanks for taking the time to document your work.

 

Very good instructions, closeup photos like this are always hard to make clear but you did good!
There is a Nylon block (could be like a Ramp) inside the key cylinder, when the Key (tooth side bevel) is inserted into the cylinder the Nylon Ramp pushes up making contact with the actuator tip.
Even with a new key & cylinder you can still move the Ramp and actuator tip up probably another .035 -.040 just by lifting the Ramp up with a paper clip.
There is a lot of wiggle room just to get the warning buzzer switch set correctly.

​​​​​​​

 

Yes the nylon block is ramp shaped. keeping in mind the switch in on the end of the ignition lock barrel, and if the lock barrel/cylinder wears over time and develops excess end play. that ramp then moves away from the switch.
One thought that I have is to build up the nylon ramp slightly. like a drop of epoxy on the tip. But unclear as to what would really permanently adhere to this plastic/nylon.
A new switch cylinder is about 50 bucks US.
Still thinking.

 

Thought I'd follow this up. I have my key alarm working like it's 1977 again. So, above I explain how to remove and adjust the key alarm switch. But it all comes down to this little nylon lever that pops out of the ignition switch barrel when the key is inserted. So I ordered a new barrel and of course that retainer that crumbled on me. Ignition barrel is extremely easy to remove and replace once your down inside the column below the turn signal switch.
Here's my old barrel.

See the white plastic tab, lower right in the photo. This hits and activates the key alarm switch.
Close up of this tab.

This is what it should look like with the key in the barrel. And in this photo it looks fine. HOWEVER, it is just gravity putting it in this position, look when I rotate the switch so the tab is up.

See, it just falls inside. (And yes the key is fully inserted). It's worn a bit on the outside compared to the new one. But only a bit. It's totally worn out on the inside. These ignition barrels are fairly inexpensive in the States. For me of course triple the price. But for most of you guys. fairly inexpensive repair. And a reminder to NOT leave your keys in the car is worthwhile in my opinion.
Of course my main reason was just that I like everything to work on my car.
Never fun saying, yup everything works except......
I don't like except.

 

I used to find these extras in new cars