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Electrical

Can anyone tell me where the switch is for the driver's cab heater/demister is supposed to be. I can see a motor mounted on it and am trying to get it working again.

If you could email a pic that would be great

Thanks you

My bus number (if any): RM2133

Re: Electrical

Hi Lorne

It`s a handle that pushes downwards close to the cab heater unit. The handle tip used to be painted white to make it more obvious in the dark but maybe that paint has faded over the years. I`ll see if I have a picture......

Re: Electrical

Found one!



This was taken in 2010 after years of storage but the cab is untouched since LT days and shows the white tip to the downward push lever and the transfer on the dashboard explaining the heater control. Could well be that your bus has had this over-painted or maybe it`s just faded.
The similar non-white tip lever next to the heater one is to open the other vent on the front of the bus.

Re: Electrical

The circuit should only be live when the alternator is charging.

Re: Electrical

Looks like the switch is activated when the vent is opened. Excellant! Thanks so much for the replies.

What is the little toggle switch for in the left hand lower corner? The box it is on also has a button on the underside.

My bus number (if any): RM2133

Re: Electrical

I think you mean the lower right hand corner?

It was a mid 1970`s addition and it`s an assault alarm. In some areas of London there had been instances of conductors being robbed and/or assaulted. The Trades Union were obviously not happy with this and asked for better protection. With a Conductor under attack and unable to raise an alarm, it was decided that the driver would be able much quicker to draw attention to the situation from the safety and enclosure of the cab. By pushing the hidden button on the underside of the box, the horn would repeatedly sound and the direction indicators on both sides would flash thus providing a visual and audible signal of a crew in trouble. Enough to hopefully deter an attacker and alert anyone in the vicinity to what was happening. Flicking the switch killed the alarm.

The instances of the box being used as an alarm were probably vastly fewer than of the box being used as a place to rest a cigarette if the driver was having a crafty smoke!

As regards the heater, yes it`s by downward pushing the white tip lever that the switch is activated. You can easily feel the metal strip switch if you put your hand in the appropriate direction when sat in the cab seat. But when standing outside the cab looking in - just as in the picture - the switch is quite visible. The lever in the `up` position is almost resting on it.

Re: Electrical

Mine has been deactivated because nothing happened when I nervously pushed the button.

Thanks for all the info.

My bus number (if any): RM2133

Re: Electrical

Well, I fired up the engine, opened the vent fully and lo and behold....the fan works! Well sort of, it screams like a banshee. Pulled the screw off the face plate and the motor comes right out. I am going to take it apart if I have to and try to find bearings but was wondering if anyone has found a replacement motor part number

On another topic, I flipped the toggle switch on the alarm and pushed the underside button and the lights flash but no alarm- I guess it has been deleted.

It amazes me that these systems still work on a 50 year old bus.

Thanks.

Re: Electrical

It`s quite a result to find things that still work on a fifty year old bus - especially if it has been laid up out of use in the open for long periods of time. So many systems on a Routemaster were designed by London Transport for the specific operating conditions of London life and with an expectation of near daily use backed up by full servicing facilities at garage level and a central overhaul works that each bus visited roughly every four years. At that point the bus body was lifted off the `running units` (as it`s not a complete chassis in the usual sense of the word) and a thorough refurbishment was carried out with parts/units being changed/replaced as required. It was 1984 when your bus last had this degree of attention followed by a few years thereafter at garage level.

In an otherwise very advanced 1950`s design, a major weakness was the saloon heating system which in its original form only delivered warm air when the bus was moving. This was a mistake. With bus stops situated frequently and central London roads gradually becoming traffic bound even during the anticipated life span of an RM, the scope for efficient delivery of heat was badly compromised. In the fairly rare instances of Routemasters running empty over any significant distance back to depot at the end of the day, the heat output into the interior was really noticeable and obviously more so than on the corresponding journey out of depot in the morning when the engine was cold. The cab heater, though, being a motor worked even when the bus was stationary. The fans did make a noise, not screaming, but noticeable.
On a really cold day it wasn`t unknown for the Conductor to get up into the cab at a terminus for a few minutes of warmth that was totally lacking on the platform! Efficient `strip` heaters came very late in Routemaster life so the vast majority never had them.

As regards the assault alarm partly working, does the horn work in normal mode?

Re: Electrical

The horn worked when we first picked up the bus but has since ceased to. We are tracking that down, I have the wiring schematics from Walker but am not sure if the assault alarm was included. Fortunately my son loves witing diagrams and working on electrics-not me.

Is it possible to find a replacement motor for the cab heater?

My bus number (if any): RM2133

Re: Electrical

I had a look in my LT Routemaster workshop manual but being a 1964 edition it significantly pre-dates assault alarms. I can actually remember how the assault alarm was first shown to union reps by a prototype fitted to RM 8 which visited garages to a schedule so that the union rep would be awaiting its arrival. Over the course of a couple of weeks it visited over sixty garages and I just happened to be in Tottenham Garage when it arrived which, I`m guessing, was around the Summer of 1975.

I don`t know about the availability of heater motors or the ease of refurbishing. But there are many who visit this site and have knowledge of such things - and possibly may have the Alteration Advice paperwork which would have been produced to acquaint garage staff with assault alarms.