speedo sensor
 

Has anyone replaced a speed sensor? I took my speedometer out to put white faces on my guages and had it sent off to be calibrated. I plugged it back in today and the speedo and odometer do not work. As I understand it, if neither the speedo or odometer work, the cause is probably the speed sensor. Need a helping hand here.

Toga82SC

It is a piece of cake. The sensor is located on the right side of the differential just above the drive axle.
remove the retaining bolt and the sensor comes right off. The wires are accessible through the access panel on rear tunnnel. Rear floorboard between the seats.

It is about a 30 minute job tops. You will need to jack up rear wheels for access to sensor.

Thanks Tony

Toga,
Ain't so. The speed signal for the speedo is as described in the previous post. The signal for the tach comes from somewhere else, somewhere in the ignition I think. If your trouble with both speedo and tach came after the gages were pulled, double check the wiring that was reconnected when they were put back.
Ned

sounds like a wiring mixup. r+r won't kill the sender.

Unless the guys who fixed your speedometer were the same guys that fixed mine, the wires should be as such:

+12V: (red/blk)(red/blu)
A: (wht/red)
31b: (brn/red)
-: (brn) (brn/red) (grn)

David
'83 Targa

Unless the guys who fixed your speedometer were the same guys that fixed mine, the wires should be as such:

+12V: (red/blk)(red/blu)
A: (wht/red)
31b: (brn/red)
-: (brn) (brn/red) (grn)

David
'83 Targa

Thanks guys, but I've still got a problem. Here's how my wires line up

+12v: (red/blk)(red/blue)
A: (wht/red)
31b: (brn/red)
-: (brn)(brn/red)(blk/brn)

I don't have a green wire, only a blk/brn.

Any ideas?

Toga82sc

Toga,

Assuming that you have the +12 V lead hooked up properly, and have power that you can measure at that terminal between 11 Volts and 14.5 Volts, and a good ground at the '-' terminal, there are only two other wires, both brown/red from the speedo sensor that matter. One br/re goes to ground, and the other to terminal 31b. If you have a measurable AC Voltage between terminals 31b and ground at the speedo with the vehicle in motion, then the sensor is good.

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Warren Hall
1973 911S Targa

Thanks guys, I'm up and running.

Toga82sc