Checking the operation of switches (Audi A4 B6)

Switches of various types activate individual consumers either directly or via a relay. Sometimes a switch defect causes a malfunction of a particular electrical system. To check the operation of switches, it is best to use a test lamp with a needle probe.

1. Find the appropriate circuit diagram.

2. First, determine which wires are supplying power. To do this, pierce the insulation of the wire with the needle probe of the test lamp.

3. Check if there is power to the switch at all. This usually requires turning on the ignition or lighting.

4. Turn on the switch. Check if there is voltage after the switch.