Does anyone know if brake lights should work when the engine is not running?

It was picked up on a Metrobus as a fault on a MOT, and supposedly rectified, but now the fault has re-occurred.

Is it a problem if they do not work when the engine is off? If it is, any ideas on how to rectify the problem?

My bus number (if any): RTL 960, RMC 1458 RM 1585, M 961, M 271 and several RTs

Update brake lights don't work at all, engine running or not. Any ideas apart from both bulbs might have blown?

My bus number (if any): RTL 960, RMC 1458 RM 1585, M 961, M 271 and several RTs

Some Metros had mercury tilt switches for brake lights, so they only work when the bus is going along. Otherwise look for the air pressure switch somewhere in the brake line or a spring operated switch under the cab.

ISTR we had a problem once with the brake switch on a Metro which was caused by the cab floor being rotten. the anchor for the spring was screwed to the wooden floor; because that was rotten, the anchor came away every time the pedal was pressed! Daft but true.

My bus number (if any): RML2532 GS67 BEA MLL721 BEA MLL738 RT2629

Thanks Roy, I'll look at these suggestions on Thursday when I do the short 200 mile trip to the garage!

My bus number (if any): RTL 960, RMC 1458 RM 1585, M 961, M 271 and several RTs

Only just seen this Brian

Metrobus Brake lights are fed from a circuit breaker that is only "live" when the bus is latched in. The switch is behind the offside headlamp panel and has a single microswitch assembly (plus another single or twin microswitche depending on the fleet number for first and second stage retarder) which are all plugged into an "H" shaped junction box. A plug and socket system called "sure seal" is used to prevent water ingress. The switches are made by microprecision in switzerland. I stock all the parts to make the assemblies although given the prices of the original components I imagine alternatives were found. Third stage retarder is done by a pressure switch.

The only mercury type switch on a metrobus that I am aware of are in the relays on the door control panel (situated behind the longitudinal seat behind the driver) except M425 on which I trialled a tilt switch to cut out the door 3mph interlock in the event of an overturned vehicle with the wheels still spinning.

I am pretty sure that RML's and Titans brake lights also operate only when latched in although my drawings are at home so I cannot check.

For what purpose should a brake light be available when the "ignition" is off?

My bus number (if any): RML2276, M1001, T806

Thanks David, it seems the problem was solved by latching in and pushing a button on the relay!
I am going to send you an E mail about an RM problem you might be able to help with.

Thanks again

My bus number (if any): RTL 960, RMC 1458 RM 1585, M 961, M 271 and several RTs