My speedometer has been going from 10 mph to 55mph. No matter what speed I'm going my speedometer wants to go to 55 mph. This isn't always the case but it is annoying when it does happen. Also when the speedometer isn't working I can hear a buzzing noise coming from the aC vent left of the steering wheel. The buzzing isn't loud but I believe the two have a connection.

My dash board also suffers from a brake light that will show its ugly head every so often. I'm not sure what triggers it going on or going off. I know when it's off and I raise my hand brake, the light will work as it is supposed to.

The dash area containing the speedometer does seem rather loose. However, I wouldn't say my plastic is the most sturdy. I sometimes shake the dash area around and the speedometer works as expected.


Thanks for reading.

 

On your brake light, check your fluid level. Emergency brake and brake fluid level trigger the light.

 

The brake fluid is filled to the tippy top!

 

Any chance of water ingress behind the dash monkeying with things?

 

Do you have a scan tool with live data? If so, you could try watching the speed on the live data PID, compared to the speedometer. It they're both giving you the same 50 MPH reading, then it might be a bad speed sensor, or something in the wiring for the sensor.
If the live data appears to be correct, then it's something wrong with the speedometer stepper motor, or wiring to the motor.

 

The fancier the scan tool the better in this case. This was one way I was able to track down computer issues on my 1999. The speedo listed correct speeds, the SLABS listed the correct speed, and the ECM listed some crazy speed. The service manuals show which pin on which computer goes to which device, so that should help you track down if you've got a wiring issue, or a computer issue, or an issue with the cluster. Mine turned out to be green crusty corrosion on the back side of the ECM connector. I have a feeling your issue will be at the SLABS, which is where the speed signal on a D2 originates. This could also explain your Brake light. If that computer has gotten wet, you might have issues with the signals coming in and out of it. For example, I had an issue with the TPS signal going to the SLABS on mine, causing the traction control and HDC lights to come on (but not that ABS).

 

The vehicle was purchased in Puerto Rico with no records!!! less than 3k miles driven and stands at 147,000 miles total. So I have no clue about 90% of her past.

 

I mean is something leaking and water/condensation/moisture sitting behind the dash causing trouble?

 

I will be checking for any moisture tomorrow after work.

Thanks for the great insight. Where is this located?? And yes, I googled this but came back with so many different answers.

 

I've located a green and a red wire that are damaged. The wires are located under the hood just above the front left wheel. I will post pictures shortly. Until then, more than likely this is my issue right?!