electronic odometer

[Guest]

HELP Please!!! I have a 1991 Buick Regal Custom 3800 4 door. I need to find out where I can get hold of a wiring diagram that shows the wiring for the electronic odometer, does anyone know if there is a sensor on the transmi [color:"blue"] ssion to send this info to the odometer? It failed the inspection on this and a shock, the shock is now done but I don't want to have to take the car to a dealer and pay through the nose. I am very handy when it comes to auto electrics and just need a wiring diagram, most manuals I have seen don't go into details on the instument cluster and instruments. can anyone help. It would be much appreciated.

[NTX5467]

The odomoter is run by a stepper motor in the electronic instrument cluster. At the dealership side of things, there are NO user serviceable parts to that cluster (other than possibly some light bulb/sockets). They have to be removed and then sent to an authorized AC-Delco service center that is approved and set up to repair the clusters (including resetting the odometer on the exchange cluster to match the original cluster). That supply chain of AC-Delco is unique and different than the supply chain of AC-Delco that supplies the AC-Delco parts we're used to seeing at the dealership level or the auto supply level.

There is a vehicle speed sensor in the transmission. It is a magnetic sensor that reads shaft speed with a "tone wheel" on the output shaft where the plastic gear used to be. Hopefully, the on board computer would have a trouble/diagnostic code in it to help pinpoint where the problem might be. It's a little bit different than just a signal generator that is hooked directly to the odometer stepper motor as the ECM is in the mix too.

We see very few, if any, issues with the stepper motor themselves. It's usually something else that helps run the motor.

You might check with your local GM/Buick dealer to see where the closest exchange center is. In reality, they probably might not sell the stepper motor to you by itself as if that didn't fix it, then it would be "their fault" so most have adopted an exchange only policy so that they know the clusters they send out are fully operational (with a applicable warranty, I suspect).

The vehicle speed sensor in the transaxle should be pretty easy to get to. Check all of the wiring connections for continuity and the wiring for condition of the insulation first. You might need a genuine Buick service manual to follow the circuits, but those things aren't nearly as easy to read as they used to be in the '60s (by my observations).

Do the simple things first . . .

NTX5467