Odometer stopped working after I trimmed some wires

[moparrob]

I have a 1975 911 that has a 964 engine and 993 G50 six-speed trans shoehorned into it.

When I bought my car both the electronic speedo and odometer were working fine. I tried to clean up some of the underhood wiring mess and cut some wires I believed to be connected to an aftermarket stereo. Since that night the speedo still works but the odometer does not.

I am assuming I cut a wire related to the odometer but I just assumed the speedo and odometer worked off the same wire(s). Apparently not.

Does anyone have any insight into what may have happened or have a schematic of the wiring for an electronic speedometer (I assume it is a 1996 speedo) that would work with my 993 G50 trans?

All help is greatly appreciated. Thanks.

[Justin@Athens]

I' thinking it is just happenstance that your odometer gear inside the speedo failed. As fas as I know there is no wiring dedicated to the odometer. I could be wrong, but I don't think I am.

[Justin@Athens]

Pelican Technical Article: Odometer Repair - 911 (1965-89) - 930 Turbo (1975-89)

[moparrob]

I think it is just a bit too coincidental it happened the same day. Plus, I think my speedo is out of a newer 1996 model since it works with the 1996 G50 trans. Does anyone happen to know if there are 2 different wiring circuits for the odometer and speedometer.

[javadog]

Rather than guess at all of this, take a look at the part number on the speedo and figure out what year it's from. Then have a look at a wiring diagram for that year.

I've never seen a speedo with separate wires to the odometer, but at least you'll know for sure.

JR

[Socbum]

You could also trace the wires from the back of the speedo to confirm they are still connected or cut.

Or, if possible, borrow a '96 speedo that you know is working and plug it in to test.

Either way, you will find the root cause.

[moparrob]

Good suggestions. I will try those.