When I bought the bug the speedometer didn’t work. The previous owner said that it had never worked for him, and I found receipts in the glove box from 5 years ago that mention the exact same odometer reading as what is currently displayed on the speedometer. When I was at Central Texas Autowerks for the parts liquidation sale and swap meet I asked Steve about it and he gave me some pointers on how to debug the issue.
The bug uses a very simple speedometer system. A cable is attached to the center of the front driver’s side wheel. The end of the cable is square and it fits into a square hole on the wheel, where it is clipped into place. Whenever the wheel turns the cable turns as well. The other end of the cable screws into the back of the speedometer. The cable is surrounded by a plastic sheath that protects it between the wheel and the speedometer. When the cable turns, it spins a small electric generator in the speedometer, causing the needle to move. This generator also turns a gear which advances the odometer.
To find the problem with my speedometer, I first took the dash apart and removed the speedometer from the dash. In a super beetle you do this by removing the dash plate that contains the switches and then pushing on the back of the speedometer, making sure to push evenly on all sides. Trying to pull the speedometer out from the front or pry it out with a screwdriver will only cause damage to the speedometer. Also, it is important to write down the location and color of each of the electrical wires before you disconnect them from the speedometer. Once the speedometer was removed I found issue number one: the speedometer cable wasn’t even screwed into the speedometer!
Next I jacked up the front of the car and spun the front driver’s side wheel. This should have caused the cable in the dash to turn, but it didn’t. Next I popped the hubcap off of the wheel and checked to make sure that the hole in the wheel was still square. It was square and turning the wheel caused the cable in the wheel to turn without a problem. This meant that the cable was broken somewhere between the wheel and the speedometer. As a last check I put the square bit in my drill and ran it in the back of the speedometer. Sure enough, the needle moved without a problem, although the odometer still didn’t work. Armed with all of this info I called and talked to Steve again. He said that the odometer gears often break and need to be replaced. I swapped my speedometer for a working one that he had and also bought a new speedometer cable at a great price! He even reset the odometer in the new speedometer to zero!
Once I had the replacement speedometer and speedometer cable, I enlisted my daughter Kaitlyn to help me do the repairs. She removed the pin holding the speedometer cable to the wheel and I pulled the cable out. A piece of cable immediately fell out of the sheath onto the floor! Next I pulled on the end of the cable that was in the dash until the cable was completely removed. I ran the new cable through the hole in the dash and down through the trunk into the wheel well. I then pushed the cable back into the wheel and my daughter clipped it back on. Once that was done I put the new speedometer in place and screwed the new speedometer cable into it. Spinning the front driver’s side wheel now caused the speedometer needle to move and the odometer to turn. Success!
Finally, I had Kaitlyn read me the notes I had made about the wire colors so that we could rewire all of the lights and instruments in the speedometer. Once that was done Kaitlyn tested all of them by turning the ignition on and testing the blinkers, hazard light, headlights, etc. Afterwards I pushed the speedometer back into the dash and replaced the dash panel. It won’t get a full test until I fix the carburettor’s gasket problem and get the car running again.
As a side note, while I had the speedometer out of the dash I hooked the antenna cable back up to the radio and checked out the fresh air box. It looks like the driver’s side of the fresh air box controls work but the passenger’s side controls do not.