odometer works but speedometer only goes up to 15mph. Whats wrong?

The odometer seems accurate but the speedo only goes up to 15mph and then wont go any higher. What could be the problem and solution?

 

You are driving through a school zone?


A binding cable can cause this, as well as a slipping drive at the magnet in the speedo housing.


The transmission speedo gear spins the cable, and the cable inserted in the speedometer spins a magnet that generates an eddy current and drives the speed wheel and that deflect the needle and there is a small spring that creates resistance with the wheel and magnet.

So, a binding or slipping can both result in a lower indicated reading.

(I use to take speedometers apart back in the 60s and use a drill to drive them, just messing around as kids, so I remember a bit about how they work, but not enough to tell you how to fix it.)

 

If the odometer still works, chances are everything is good up too the speedo head.
Sounds like something is preventing the speedo needle from going past 15 mph.
JUST THOUGHT OF THIS: Do you have the "Speed Minder" speedometer? You set a knob so it buzzes when you reach your preset speed?
Theres a tiny micro switch, contacts, whatever you wanna call 'em that are spring loaded, when the needle hits the contact, it winds the spring, which closes the contacts, the needle doesn't go any higher, and the "key in ignition buzzer" buzzes:shock:

 

yes I have the speed alert feature. no buzzing though. I have the speed alert set at 60 but the needle wont go higher than 15 or so.

 

Pull the cluster and take a look:TU:

 

that green with the white letter rallys looks awesome! especially overcast days.

i actually have an extra couple clusters with speed alert. Ive had them apart and still cant make sense of them.

 

I have just the opposite problem.
My odometer is dead on accurate.
But, the speedometer shows 30%-33% faster than actual speed.
I've been told that it has a low resistance in the speedometer's magnet.
Maybe yours has too much resistance in the magnet, or in the cable.

 

very interesting. I wonder how hard it is to replace the magnet from my extra speedos? or eliminate the resistance. Maybe some fuzz balls or dirt or something?? compressed air?

 

I never tried to work on speedometer.
I think there might be gremlins in there. I'm afraid to open it, those gremlins might get out....