KSL '67 101234

My 1967 Roadster came with the U15 Speed Warning Indicator option. I guess what is supposed to happen is that when the speedometer needle lines up with the speed warning indicator needle, which the driver sets by turning a **** on the dash, a warning buzzer located under the dash starts buzzing.

In my case, the buzzer does not sound and the speedometer needle hangs up at the speed warning indicator needle’s setting. For example, if the speed warning indicator needle is set at 70mph, the speedometer needle will stop at 70mph when that speed is reached. If my speed is 75mph, the speedometer will still read 70mph until I move the speed warning indicator needle past the speed of travel, say a new speed setting of 80mph. As soon as I move the speed warning indicator needle past the speed the car is traveling the speedometer rapidly climbs to the correct speed, in this case 75mph.

Until recently the speed warning indicator's white wire connected to the warning buzzer on the dash cross brace was not hooked up to the brass connector lead located on the back of the instrument cluster. It was hanging loose under the dash. Before I connected the white wire the speedometer's needle would move without hanging up at the speed warning indicator needle setting, and at the point of aligning with the speed needle set point would not set off the warning buzzer. When I traced the white wire to the buzzer and found out through forums where the wire attaches, I thought cool I've located the mystery connection where the white wire attaches and all would end fine. Well not so!

Question, is the buzzer bad and causing resistance when the speedometer needle lines up with the speed warning indicator needle? Is the problem with the speedometer's needle and how it makes contact with the speed warning indicator needle?

I tested the buzzer with a 12-volt battery and it works fine. In fact, I took off the buzzer's cover and the inside looks as clean as the day it left the factory.

JohnZ

I haven't been inside a U15 cluster before, but it sounds like an internal issue where the actual contact takes place between the speed cup and the ground point that triggers the relay; it's going to need help from an instrument specialist like Joe Ray Parts.

67vetteal

Your Speed Indicator needle, (Red), has a small flat arm on it that moves along with the Speed Indicator needle. Upon reaching the Speed Limit Indicator it makes contact with a fine wire coil that is integral to the Speedometer shaft. This completes a circuit for the Buzzer to sound. If you remove the Speedo and examine these two contact points you will most likely find the Flat Arm is getting snagged on to this coil. A Jewels Loop will help you see as these parts are small. Not rocket science and you can most likely fix it. Al W.

Nowhere Man

that's what sounds like to me. the contacts inside are very fragile.

to check your buzzer just put 12 volts to it with a good ground. if it buzzes its good.

Mike67nv

I tried to fix my speed warning speedo but gave up for a lot of reasons. Mine needed to be refaced and some of the worm gears needed replacing so I had it refurbished by Corvette Specialties of Maryland West. The U15 speedo is unique in a lot of ways – different main needle, plastic face attachment screws and fiber washers to insulate the face plate, a brass strap behind the face plate to complete the ground, and the list goes on and on. The main needle has a tiny hairspring on the backside that contacts a peg on the adjustable set needle and completes the path to ground.

The first pic below shows my non-restored speedo with the main needle removed. It’s at the top of the pic, unfortunately you can’t see the hairspring on the back, but you can see the peg on the set needle just to the left of center. If your speedo has never been touched, you might get away with a clean up and re-assembly. If not, you will probably need to use a professional. I had talked to a couple and found not all had experience with the U15 speedo and not all could do refacing. Corvette Specialties of Maryland West was able to do everything I wanted and I am pleased with the results.

The second pic is the refurbished tach and speedo – now totally functional, recalibrated and looking like new.

Mike67nv

Looking at your post again, I see that I forgot to answer your question. I believe the hairspring on the main needle is hanging up on the set needle or contact peg. Disassembly of the speedo is probably the only way to see the exact cause.