Need electrical help.

[porscheboy1]

The speedometer odometer is not working in my 82 911 SC. I have another complete speedometer in a 78 911SC that is in the process of restoration and I took that speedometer, which I know nothing about, and put it in the 82 car. Upon driving the car nothing worked in the speedometer. I put the original speedometer back in and now that speedometer does not work either. I then switched speedometers again so that I can send the 82 speedometer out for repair. I reinstalled the 78 speedometer in the car just to have something to hook all the wires to. I drove thew car again and the speedometer needle began oscillating wildly and finally pegged at zero mph. I parked the car and turned the ignition off and the needle pegged the other way at 150mph. While sitting in the car I realized I had made a big mistake by forgetting to disconnect the negative battery terminal before doing all this. Could I have damaged the speedometer sensor in the transmission? What else might be damaged? Any advice will be greatly appreciated. John

[86 911 Targa]

Originally Posted by porscheboy1

The speedometer odometer is not working in my 82 911 SC. I have another complete speedometer in a 78 911SC that is in the process of restoration and I took that speedometer, which I know nothing about, and put it in the 82 car. Upon driving the car nothing worked in the speedometer. I put the original speedometer back in and now that speedometer does not work either. I then switched speedometers again so that I can send the 82 speedometer out for repair. I reinstalled the 78 speedometer in the car just to have something to hook all the wires to. I drove thew car again and the speedometer needle began oscillating wildly and finally pegged at zero mph. I parked the car and turned the ignition off and the needle pegged the other way at 150mph. While sitting in the car I realized I had made a big mistake by forgetting to disconnect the negative battery terminal before doing all this. Could I have damaged the speedometer sensor in the transmission? What else might be damaged? Any advice will be greatly appreciated. John

John,

When disconnecting the speedometer,with the key "off", the red wire is first, then the rest.

When reconnecting the speedometer, with the key "off", the red wire is last.

I suspect that you may have damaged the IC on both units,
which may be hard to find.

pm me as needed.

Good luck,

Gerry

I think that this is a 3.2 unit.

[porscheboy1]

Thanks, Gerry. It didn't tell me that in the Bently manual. I'll reconnect per your instructions and if it is still damaged I will send it off for repair. Do you think anything else id damaged?

[86 911 Targa]

Originally Posted by porscheboy1

Thanks, Gerry. It didn't tell me that in the Bently manual. I'll reconnect per your instructions and if it is still damaged I will send it off for repair. Do you think anything else id damaged?

Not off-hand.

Why don't you call Gary at Paul's, 310-374-3017

By the way, he does a lot of work for Pelican.

Best,

Gerry