I am trying to get the speedo to work again, see other thread below "no speedo".

I have checked what wiring I can reach, replaced the VSS and without pulling the trans to see if someting is broken in there this seemed to be the next logical step.

Any opinions?

 

Ok, im assuming you're talking about the 95 TA. First of all, the vss you replaced, did you look into the hole and see if the reluctor wheel was still in place on the output shaft? I believe you have the electronic speed sensor which drive on magnetic impulses created by the wheel on the output shaft which creates an AC voltage in the sensor. So the first thing you're going to do is jack the car up and put stands under the rear end so you can put the car in gear and let the wheels spin free. Hook up a voltmeter to the 2 wires (through the connector end if possible, while plugged into the speed sensor). If you dont have the right equipment, go spend $30 at sears and buy a craftsman voltmeter, you'll use it more than this one time, believe me. Personally, I use paper clips sharpened to a point as probes (you can stick them through wires, or into the connectors where the wires go in). Let the wheels of your car spin in gear, and set the voltmeter to the AC voltage setting, low range. You'll be looking for something between 0-5 volts i believe. The faster you go, the more voltage induced. The PCM converts this voltage to figure MPH. If you have voltage there, we need to move to the next step, which is go to the PCM, and test for AC voltage at the correct pin locations to see if the signal is reaching the PCM. If you're still good there, we move to the dash cluster next. I can find out which pin points you need to check at the PCM at work tomorrow, let me know if you need that info but for now check the other stuff first. Good luck, and dont forget, if you ***** through the wires, make sure you cover them back up properly, either with shrink tubing or something. Dont leave the hole open as it WILL corrode and cause issues in the future.

 

Yes it is a 95.

I have an electronics backround so doing these test are no problem.

If the "reluctor wheel" looks like a gear then, yes it is there.

I will check for AC at the sensor tomorrow.

 

Performed a few tests tonight.

Put a DVM on the VSS, started it up, put it in drive, let off the brake and the meter showed ~5VAC. So the VSS and reluctor seem to be working ok.

Moved the meter up to the PCM, no voltage.

Ohmed out the wires and both of them are open, so all I need to do is run new wires for the VSS.

Thanks for the help.

 

nice troubleshooting! Did they burn on a header or something?

 

I have no idea. YET.

I am going to try to remove them so I can find the culprit, but either way I am going to home run the wires.

 

Where is the wire for the PCM for the speedo? Mines out too...

 

I only have the books for a 95, I am not sure if they are the same in 97 or not. I will look and let you know anyway.

 

It is fixed!!!