Seat Belt Warning

North America 1972-73:

North America 1974: More information on this system can be found here

North America 1975-on:

UK 1977-on:

Note: To starter and brake warning circuits.

Described as a 'time delay unit' in diagrams but 'unit-buzzer/timer' in the Parts Catalogue (I'm sure I've seen it described as 'a limited period warning' somewhere but can't find it now). According to Clausager it will "flash if the ignition/starter was operated without the driver being buckled up", however John Keane on the MGOC forum says his flashes all the time when the seat belt is not fastened. It doesn't have an ignition switched 12v supply only a a 'permanent' 12v supply from the purple circuit so what switches it off? The warning lamp is fed from the fused ignition supply, so that goes out when the ignition is turned off, and is also feeding 12v into the module via the bulb that may do something instead of being just an earth switched output to light the bulb. If it comes on whenever the belt isn't fastened why does it need the module at all? Why does it need an input from the starter unless it's function is to turn on the light as a test during cranking regardless of whether the belt is fastened or not, and the timer causes it to flash for a while then stop?

All three types of module can be found behind the centre console.

Belt switches (UK 77-on at least) have a normally-closed connection with the seat-belt unfastened and an open connection when fastened.

The UK seat-belt and handbrake switch wiring:

The warning lights: (MGB GT LE Blog)