This part of site is an attempt to organize and add to the web resources for the Rover SD1
to form a cohesive and easily usable guide for those of us without easy access to
expert repair and/or advice. It is not offered in any way as a definitive source
and we take no responsibility for any errors that may exist.
Webmaster Rene Winters
Now the windscreen wipers.
A 2-speed system is fitted to all models.
Control of the motor unit (1) is by means of a switch (2) mounted on the steering column. On 2600 and 3500 models a delay unit (3) is incorporated into the circuit to provide a intermitted whipping facility.
The delay unit comprises an electrically heated bi-metallic switch. As the moving contacts heat up it brakes the power supply to the motor. On looking, the circuit is remade and the whispers operate again.
The 2-speed wiper motor is located beneath the right hand bonnet grill.
The motor has a build in parking switch which functions in al modes of wiper operation.
When the wiper motor is switched on the current, shown in red, enters the column switch at point 3 and leaves at pin 5. It then enters pin 5 of the motor connector and the wipers operate at low speed.
If high speed is selected, current leaves the column switch at pin 1 and passes via pin 3 of the motor connector to the high speed brush.
When intermitted operation is selected, current flows directly to pin 4 of the delay unit. It leaves at pin 3, passes through the column switch and then through pin 5 of the motor connector to the low speed brush. At the same time current, shown in green, flows through the heating coil in the delay unit and through the column switch to earth.
As the coil heats up the switch contacts in the delay unit change over. Current then flows directly to pin 4 of the motor. It passes through the parking switch and leaves at pin 2. from here it passes through the delay unit, to the column switch and from here to the low speed brush. The current continuous to flow through the delay unit heating coil unit the park position is reached. Failure of the delay unit will not affect the normal 2-speed operation of the wipers.
A suspect unit should therefore be checked by substitution.
If the wipers fail to operate a simple method of determinating whether the fault is in the motor unit or in the column switch is to use a test plug. This is a wiper motor plug made up with red, blue, yellow and white leads. During testing make sure the screen is kept wet. Fit the test plug and connect the red lead to the battery supply and the blue lead to earth. The wipers should operate at low speed. To test high speed operation substitute the yellow lead for the red lead. Then stop the wipers in mid travel. Now test the park switch. Connect the red lead to the battery supply and the white lead to the negative terminal. The wipers should move to their park position and stop. If the motor operates correctly the fault lies in the column switch or connecting leads.
The headlamp wash/wipe system|
We will end this webpage section by looking at the headlamp wash/wipe system fitted only to the
The system comprises a control switch (1) a relay (2) a programme or delay unit (3) a single speed wiper
motor (4) and an electric pump (5)
A larger water storage reservoir which serves both the screen and headlamp wash/wipe systems is also
fitted. The system is protected by this inline fuse located near the water storage reservoir.
The circuit is energized through the lighting supply line relay located behind the passengers glovebox
Whenever the vehicle's lights are on the relay (49) supplies current shown in blue to pin 2 of the
Now let us see what happens when the control stork is depressed
Barry in mind that the power supply still exists at pin 2 of the delay unit. Operation of the washer
switch (95) energizes the screen washpump (96) and the headlamp wash/wipe relay.
This circuit is shown in red
A relay completes the earthpath, green, from the delay unit. Current can then pass through the delay
unit to the headlamp washer pump and the wiper motor. This is shown in blue. The pump and wipers operate
for a five second period after which the wipers return to their rest position.
Now troubleshooting the circuit. If the failure is total, first check the inline fuse and then the
screen-washer fuse located in the fuse box
Then check that the connections to the delay unit (1) and the relay (2) are secure
Next switch on the ignition and the lights and check the input voltage to the relay coil.
Then check the operation of the relay.
If the relay is all right, the delay unit is faulty and must be replaced.
Now some partial failure situations.
First the wiper motor fails to operate.
Remove itīs protective cover, disconnect itīs multi-way connector and replace it with a test plug.
Then follow the screen-wiper test procedure described in the windscreen section.
Although in this case the motor has only one speed.
Next washer pump failure. First check itīs earth connection then with the lights on bridge terminals 2
and 3 of the delay unit. Replace the pump if it still fails to operate. That completes this section on
the headlamp wash/wipe system.
Special thanks to Drs. L. de Boer.