How to Testing and replacing a flasher unit

How to Testing and replacing a flasher unit

Here you can get Testing and replacing a flasher unit. Here we provide Changing and Testing flasher unit, Fast or slow flashing ect.

There are two basic types of flasher unit. One is operated by a piece of wire or a bimetallic strip which expands and contracts because it is heated by the current; the other may be a relay operated by a transistorised circuit. The first type is straightforward to locate if it’s performing at all due to the click sound it makes. to see whether it’s faulty, use a circuit tester or test lamp within the way described below.

The transistorised type doesn’t make a clicking sound, and can’t be checked with a circuit tester. It are often damaged by a brief circuit. The only way to determine if a transistorised type is faulty is by eliminating all the opposite components within the circuit.

Changing the flasher unit

The flasher unit may be fixed by a small bracket held by one or two self-tapping screws, or a push fit in a spring clip, or plugged into the fuse box. Or it’s going to just hang by its wiring behind the instrument panel. Except for the plug-in type, there’s a risk of confusing the wires. Label them before removal.

A two- terminal unit has no terminal for the sunshine on the instrument panel, which is connected to the switch instead. Replace the unit with one among an equivalent type. the sort number is usually stamped on the metal cover.

Tracing faults

If the indicators stop working completely, first check the fuse (See Checking and replacing fuses ). an indication of a blown fuse is that other components within the same circuit stop working. Your car handbook or service manual should tell you which of them components are within the circuit.

Fit a new fuse. If it blows again, search for a brief circuit. If the fuse is sound, check out the stalk and hazard-warning switches and therefore the flasher unit. Remove the stalk-switch cover to check the unit. The flasher unit may be near by, or behind or under the bonnet or plugged into the fuse box (See ). check that all the connections are sound and the wires unbroken.

Testing the flasher unit

To test the conventional type of flasher unit, use a circuit tester between the terminal marked B on the unit and therefore the earth. activate the ignition. If the supply side of the unit is working, the bulb should light. If it doesn’t , search for a break within the wiring between the unit and therefore the fuse box.

If the tester lights, test between the terminal marked L and the earth. The lamp should light; it may flash. If it works, the fault is within the switch or the wiring; if not, the flasher unit is faulty.

Fast or slow flashing

Flashers are required by law to flash between 60 and 120 times each minute – that’s , between once and twice a second. If the speed of flashing becomes unusually fast or slow, you’ve got a conventional type of unit – in the transistorized type the speed is constant. If you have a three-terminal unit, flashing that’s faster than normal indicates one blown bulb, or a corroded or disconnected bulb holder.

Flashing that’s slower than normal indicates that there is a partial short circuit. With a two-terminal unit, slow flashing indicates a blown bulb; fast flashing means a partial short.

Hazard warning lamps

Hazard warning lamps are fitted to all or any modern cars, to be used only the car is stationary and a hazard to other drivers. Operation of the hazard warning switch bypasses the normal switch, using the flasher unit to send signals to all or any the indicator lamps simultaneously.

Heavy-duty flashers

If a car is to be used for towing a caravan or other type of trailer, an electrical connecting socket must be fitted for the trailer’s lights, along side the tow bar. The existing flasher unit isn’t powerful enough to serve the extra lamps, and so a heavy-duty unit (or an extra remote unit) must be fitted. The heavy-duty unit operates the car’s normal flashers when driving without the trailer, with no effect on flashing speed and with no extra load on the lamps.

The unit has an extra terminal prong for the extra flasher warning lamp (also required by law) for the trailer connection. The terminal prong may need to be bent to a 90 degree angle and therefore the warning-lamp terminal fitted on thereto before plugging within the heavy-duty flasher unit. The additional warning lamp are often fitted permanently into the instrument panel, or mounted on a bracket where the driving force can see it.

If the car flasher unit is found in an inconvenient place, like inside the instrument panel, tow-bar centers can supply a further remote flasher unit rather than a heavy-duty unit. A remote unit are often placed anywhere convenient, like within the boot. It must be wired into the existing flasher system. Follow the maker’s instructions when fitting it.

The switch on the steering column

On latest cars with multi-function switches on the steering column , the connectors are complicated – patience is required to see them. The switch may are bent, broken or dirty connections which prevent it form working on one or each side .

Connect the tester between one output terminal of the switch and therefore the earth. With the ignition on, turn the switch thereto side. The lamp should light. If it doesn’t , the switch is faulty. If it does, look for a wiring break break between the switch and therefore the lamps thereon side.


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