Troubleshooting

Using a Multimeter to diagnose pedal problems.

Testing Potentiometer Supply and output voltages.

Each pot has three connections:

  • Supply 3.3 volts (Red) (*If using a Bodnar cable the voltage will be 5 volts)
  • Ground (Black)
  • Signal (Green, White or Orange)

With the pedals connected to the wheel measure the voltage between the Red and Black wires on each potentiometer. You should get a reading of approximately 3.3 volts. If your not getting the correct voltage here it can indicate damage to the wiring.

Measure the voltage between the signal wire and the black wire on each potentiometer. You should get a reading between 3 volts and 0.5 volts depending on the position of the pedal.
If the signal voltage is staying low then it indicates either a potentiometer fault or the signal wire shorting to ground.
If the signal voltage is staying high then it indicates either a potentiometer fault or the signal wire shorting to supply.

The copper wires inside the cable are very thin and are often damaged by repeated bending or crushing. Check for variations of voltage when moving the cable around, especially in high risk areas for example where it leaves the pedal housing.

Testing for cable damage.

Damage to the cable between the Logitech wheel and pedals is very common. The wires are very thin and are easily damaged by repeated bending or crushing.

Cable damage is easily mistaken for problems with the pedal potentiometers.

A multimeter is needed to carry out the following checks.

To check for breaks in the wiring measure the resistance of the wires between the potentiometer spade connectors and the D connector at the end of the cable (see pinout diagram below). If the wires are in good shape then there should be around 1 ohm resistance. If the resistance is higher then it can indicate damage to the copper wires or a problem with the crimped spade connectors. The black and red wires are daisy chained between the three potentiometers and the crimps are another source of potential problems.

To check for shorts in the wiring you must first disconnect all the potentiometers from the wiring loom. Make sure that all the spade connectors are kept away from each other before starting any checks. Check that there is only continuity between the spade connectors and their associated pins the in the 9 pin connector.

If you detect damage to the cable it is possible to repair it. We will add advice on this at a later date.