Semaphore Indicator Problems

PG Car 25

When the indicator switch is activated the required semaphore arm, or trafficator, should immediately rise to the horizontal position with the bulb lit.  If the bulb is not lit it can easily be replaced, but the arm may only partially rise or not do so at all.



 If the trafficator arm fails to rise this may be due to any or all of the following:

1.    Poor connections at the trafficators themselves or the junction box from which which they are supplied with power.

2.    High resistance line or lines.

3.    Poor switch contacts.

4.    Poor earthing.

5.    Distorted trafficator arm or pinched armcase (housing).

6.    The solenoid plunger of the arm is rusty, or the hinge is tight.

Rust and stiffness of operation may be overcome by applying a fine spray of penetrating oil on the plunger and the hinge.  If there are no immediately obvious mechanical defects and items 1, 3 and 4 are satisfactory then the problem is 1. poor connections somewhere in the wiring.  This is common, especially on 6 volt systems. 

The first place in the wiring to check is the point where the wires exit the steering column and are joined to the main loom using bullet connector(s). 

Any clamp at the base of the steering column tube must have a clean and tight grip on the end of the stator tube within the column so as to form a good earth connection (Item 4), which is essential for ensuring that the indicator and horn control head work properly.


This short article is based upon notes published in Carrycurrent Chronicle Vol 2, No 1 December 1935.

See also:

Servicing Hints for Direction indicators.