My speedometer stopped working on me and was wondering if someone knew how it works? The lights are still working, but the needle don't move. It's a 72 btw.

The speedo is driven by a cable that is connected to the transmisison.

In between the cable & the transmission is an angle drive. (It's a right-angle looking doohickey, smaller than a raquet ball.)

There are a few areas for failure in the system:

1. Angle drive failure.
2. Cable broken.
3. Speedo unit failure.

I'd disconnect the cable from the angle drive and spin it with a drill, while having a friend watch the speedo. If the needle moves, you may have isolated the issue to the angle drive. If the needle doesn't move, the cable or the speedo may be suspect.

Hope this helps. I'm sure others will chime in with more detailed advice.

-Rusty

speedo works off a cable run by a gear (the angle drive) at the rear of the transmission. easy procedure to test speedo is to disconnect cable at angle drive and spin using a drill. you must spin in correct direction. this basically tests from cable forward so you can determine if cable and speedo are good. next is to disconnect the cable at the rear of the speedo (ouch, my hands hurt due to the small space and sharp metal). spin speedo in correct direction to test speedo.

I took my speedo out of my Karmann and hooked it up lol. Fit perfect in the Porsche too. Does not work, but I know my Ghia speedo does so it is either the cable or the angle drive. Thanks guys!

If I remember correctly you need to spin the cable in counter clock-wise.