Fiat Bravo Quiz
Electrical system

Checking the switch for continuity

In this manual: Electrical system
Dear Reader — 1Engine — 35Engine lubrication — 3Engine cooling — 10Ignition/spark plugs — 14Fuel system — 10Petrol fuel injection — 13Diesel injection system — 13Exhaust system — 7Clutch — 7Transmission / Gearshift / Automatic Transmission — 5Front Axle — 11Rear axle — 4Steering — 9Wheel alignment — 1Brake system — 22Wheels and tyres — 10Body — 34Heating — 6Electrical system — 39Lighting system — 14Instruments — 7Windscreen wiper system — 8Vehicle care / tools — 6Jump Starting / Towing the Vehicle — 3Jacking up the vehicle — 1Fiat Bravo / Brava Maintenance Schedule — 1Maintenance — 38Wiring diagrams — 5
~2min read

Most electrical consumers are switched on and off by a manually operated switch. In addition, there are switches that are operated automatically. These switches include, for example, the oil pressure switch and the brake fluid level sensor.

In principle, a switch has the function of closing and interrupting the circuit. There are switches that interrupt the earth wire and switches that interrupt the positive current.

Checking the switch for lamps and electric motors

  • Remove the relevant switch.

  • Simple switches have only 2 terminals for the cables.

    In this case, voltage (+) must always be present at one terminal, and also at the other terminal after switching on. There are also switches with several terminals.

    For these switches, use the wiring diagram to determine which terminal must have voltage; if necessary, switch on the ignition beforehand.

  • Use a test lamp to check whether voltage is present at the switch.

    If the test lamp lights up, operate the switch and check whether voltage is also present at the output terminal.

    If so, the switch is confirmed to be working.

  • If there is no voltage at the input terminal, there is an interruption in the supply line.

    Use the wiring diagram to check the voltage supply and, if necessary, install a new wire.

Checking the sensor switch

Sender switches are, for example: oil pressure switches, brake fluid level and coolant level sensors.

  • Connect a continuity tester (test lamp or ohmmeter) to the input and output of the switch; to do this, disconnect the wires from the switch. Note: switches screwed into the engine block generally have no ground wire, because the switch housing uses the engine block as the ground connection.

  • With the switch closed, the continuity tester must indicate continuity. An ohmmeter is best for this: with the switch closed it must show 0 Ω, with the switch open o Ω (infinite).

  • The function of coolant or brake fluid level warning switches, for example, can be checked most quickly as follows: with the ignition on, disconnect the supply wire from the switch and hold it against a good ground point, for example the engine block.

    If the warning lamp in the instrument cluster now lights up, the fault is in the switch.

    The oil pressure switch is a special case: with the engine stopped, the contact is closed (warning lamp on); the switch only opens once a certain oil pressure is reached.

Test yourself

A quick Fiat Bravo quiz: every answer comes with an explanation and a link to the manual page.