Help! How do you test the speed warning buzzer?

[Racemic]

Hi Everyone,
My '68 has a speed warning buzzer that has always been silent. The speedometer was rebuilt professionally so I'm fairly confident that the speedometer is not the problem but I need to test the buzzer to be sure. Despite the three prongs on the buzzer only two are used. The red wire in the harness goes to the bat tap in the fuse panel and the white wire goes to the post on the back of the speedo. I'm assuming that is a ground. Presumably, a bench test is as simple as connecting a 12V source and a ground appropriately - but when I do that, the buzzer is still silent. Am I missing something?

 

[SVO]

As I remember it, you have power to the buzzer module and the ground for the buzzer is thru the speedo. When the speedo needle meets the buzzer set point needle, the circuit is closed and the buzzer sounds. Also, seems like there was a minimum speed set point for the buzzer to work, something like 20 or 30 mph??? When you did your test, did you use a variable speed drill motor to spin the speedo? Does your buzzer work when you add power and a ground to the buzzer module?

 

[Racemic]

I wanted to isolate the buzzer from the system so I removed the buzzer from the car to test it. I supplied 12V to the prong on the buzzer that used to be connected to the battery tap in the fuse panel and I attached the prong that had the white wire attached to the speedometer to ground. Nothing happened.

 

[SVO]

Then I would say that your buzzer module is bad. Which is bad, as that probably isn't a commonly available part.

 

[Racemic]

Solution

I obtained a replacement buzzer. I was testing my old one correctly and it was bad. The red wire on the harness supplies 12V to the prong labeled "2" on the buzzer and the white wire on the harness supplies ground to the prong labeled "3" on the buzzer. When both connections are made you get a buzzing noise if it is good.

SVO was correct, the buzzer was a bit of a challenge. Here's how it went: After about a hundred Google searches for variations of "corvette speed warning buzzer" and "part # 1361529" (from the AIM) I learned that this part was also used on camaros, chevelles, and corvettes. Prices ranged from $63 at musclecars.net to a NOS Delco Remy on ecrater for $280. Interestingly, the musclecars.net site had a photo of this part for sale which looked exactly like mine but labeled as part # 1386278. I added this number to my Googling and found both numbers listed as a "speed safety buzzer" on Buickfarm.com for "62-68 all" with a photo that appeared identical to mine with the exception of a ground prong on the buzzer housing. Price: $42. What the heck, I ordered it. Four days later the buzzer was in my hands, bench tested, and buzzing like crazy.

 

[SVO]

Kudo's for finding a (relative) inexpensive replacement buzzer. If you hadn't been able to find one, I would think that one should be able to adapt a buzzer off of a later model GM vehicle. Like the seat belt warning buzzer or headlights on buzzer.

edited to add: It's not uncommon for GM to superceed a part for a later similar part, hence the different part number from your original part.

 

[kernal99]

Source for Buzzer

I know this is an old post but I'm on the search for a new buzzer if anyone has any info. I've attached a picture of mine which I think is bad because I can't get it to buz and I have continuity between terminals 1 & 3. I'm also trying to find the connector that attached to the round brass lug on the back of the speedo.
Any help is appreciated.