Key Buzzer Function?

[Tom L.]

I finished assembly of a T/T column and I think the key buzzer switch isn't functioning properly. I have a meter on the wires from the switch to check continuity.

The switch is installed properly and is not damaged in any way. I think the malfunction is related to the plastic part that comes out of the lock cylinder to depress the switch.

The switch is closed (will buzz) with the key in or out. The switch opens in the run and crank positions. Am I correct that the switch should also open in the lock position with the key removed?

[Lawrence M.]

Re: Key Buzzer Function?

Tom,
According to the 68-72 Ops & PV Manual, "with the drivers door open and the key fully in the ignition switch, the buzzer in the horn relay should sound. Check that the buzzer sounds with the ignition switch in the ACCESSORY,LOCK or OFF positions. Removing the key or closing the door silences the buzzer."

Larry

[Tom L.]

Re: Key Buzzer Function?

Thanks Larry. That's my understanding of how the system works as well. It seems to me that to make it function that way, the switch needs to opened by the retraction of the plastic tab in the lock cylinder when the key is removed. Mine is not doing that now. I'm just trying to define what the proper operation is of the lock cylinder/buzzer switch before I take this thing apart again.

[Jim S.]

Re: Key Buzzer Function?

The following is a scan of a pretty complete trouble shooting procedure for the key buzzer operation.

http://jimshea.corvettefaq.com/wp-content/uploads/2006/01/KeyBuzzerDiagnosis.doc

I am thinking that if the plastic tab on the lock cylinder is stuck in the extended position, the buzzer would actuate all of the time (even in the RUN or START positions) except when the door is closed.
Jim

[Pat M.]

Re: Key Buzzer Function?

The plastic housing on my 70's T/T buzzer switch had a barely noticeable crack near the tab that the key pushes in. I believe the crack came from age and the key pushing it in and out over and over.

As a result, the housing allowed the switch contacts to continuously touch, and thus the buzzer went off all the time, even with the key out, except when I closed the door. This might be your problem. I had to change the switch with an NOS one I got from Dr. Rebuild. Good Luck

[Jack H.]

Re: Key Buzzer Function?

Yes, if lock cylinder's plastic arm doesn't retract freely upon removal of the key, she'll continue to buzz!

The mechanism for retraction is the force exerted by the keyminder switch in the column. Factory originals are NOTORIOUS for breaking.

The original switch was packaged in a clear lucite plastic housing. What 'kills' it is heat/age. Sun beating on the steering column tends to 'cook' the key minder switch resulting in the clear plastic housing aging and cracking.

Once the switch housing 'lets go', there's insufficient retention of the two sides of the metal reed switch inside the housing. That changes the geometry of the switch contacts and you wind up with either no buzzing or constant buzzing.

To verify the integrity of the switch, you need to remove it (following the service literature's R&R guidelines). Once out of the column, GENTLY remove the switch from its metal retainer and carefully eyeball its condition...

[Tom L.]

Re: Key Buzzer Function?

Thanks guys. I don't think that the plastic tab is retracting into the cylinder with the key out. Looks like its time to break the column down again.

[Tom L.]

Re: Key Buzzer Function?

I took it all apart again. The switch is fine. As suspected, the problem is that the plastic tab won't retract when the key is removed. Time to send the cylinder back to the locksmith, again.
Thanks for your help.

[Pat M.]

Re: Key Buzzer Function?

Tom - as was noted, a little plastic tab on the buzzer switch is what pushes the lock cylinder's plastic arm up when the key is out. When out of the column the lock cylinder's plastic arm should freely slide in and out with no resistance at all.

When you say your lock cylinder arm won't retract, do you mean it's actually frozen and won't move freely back and forth when it's out of the car? If it does move freely, I'd think the buzzer switch tab is the problem and is providing insufficient force to push the lock cylinder arm back up.

Assuming your cylinder arm moves freely, check the buzzer switch VERY closely near the plastic tab. I had a crack there that was VERY hard to see, and that was the cause of my problem.

[Tom L.]

Re: Key Buzzer Function?

Pat,

The tab moves freely with no resistance only when the key is in the run or start position. With the cylinder in the lock position the tab remains out, with or without the key. I can't even push the thing back in.

The cylinder worked fine until I sent it out to be "re-conditioned" and to have a correct set of keys made. I got it back the first time, turned the key once preparing to install it and something inside the cylinder fell apart and jammed. I just got it back from the vendor, and now this. I wonder if a new cylinder is still available?

[Pat M.]

Re: Key Buzzer Function?

If you can't manually push the lock cylinder plastic arm up (into the keyway) in the lock position when no key is inserted it sure sounds like that's your problem.

I don't know if a new correct (restrictive) cylinder is still available. Of course you can get NOS and repaired correct cylinders but they're not cheap.

Good luck.

[Jim S.]

Re: Key Buzzer Function?

I think that your real problem is in your above paragraph:

"The cylinder worked fine until I sent it out to be "re-conditioned" and to have a correct set of keys made. I got it back the first time, turned the key once preparing to install it and something inside the cylinder fell apart and jammed."

You need to find a competent place to re-condition your lock cylinder.

Unfortunately, I don't have any suggestions as to a lock smith or service.

Jim