Important!! 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.

Bulb Failure System One of the Rovers many safety features is the bulb failure monitoring unit. Failure of a side of stop lamp will cause the panel mounted warning lamp to glow. The unit is located inside the car behind the left hand rear lamp cover.

Letīs see how it operates. Inside the unit is an integrated circuit arrowed which is energized while the ignition is on. When the engine is cranked a signal shown in red is send from the ignition switch 45 to the monitoring unit 43. The monitoring unit completes the circuit shown in blue through the warning lamp 70 causing it to light. This is a test for the bulb which should go out once the starter is released.

From the stop lamp switch 65, the stop lamp circuit yellow is completed through the monitoring unit 43. the side light circuit red is also completed through the monitoring unit. The side and stop lights receive current through these resisters on the left of the unit. The integrated circuit senses the failure of any lamp in terms of a voltage change and causes the warning indicator to glow.

Any failure to the unit itself can be overcome temporarily by removing it from the harness taking of itīs cover, refitting the circuit board the opposite way around and finally reconnecting the unit to the var. but this is only a temporary measure as the unit must be replaced at the earliest opportunity.

If a tow bar is to be fitted to the vehicle the stoplights should be connected at point 1 and the sidelights at point 2. Both on the switch side of the monitoring unit 33 not on the output side. Otherwise the additional current drawn through the resisters would cause a heat build up and could result in failure.