Hi,

Does anyone have an electrical wiring diagram for an RT?

I have problems with the wiring for the indicators - they are shorting out in multiple places. I found the ears are shorting; I also found shorting elsewhere between the ear/switch/fuse. Coupled with the fact that some of the wiring has me completely confused...

It's all very new to me, but I need to get to the bottom of it as the batteries are being drained.

I have an Automobile Engineer article from 1943 that details the engine/gearbox/chassis/brakes/steering/axles - just about everything except body and electrics.

Alternatively, does anyone know where I can purchase an electrical wiring diagram?

Thanks in advance.
Steve

My bus number (if any): RT3316

I've got one somewhere but seem to remember dropping varnish on it, so it's stuck together and very shiney. the wiring on most buses of that era is rotten and needs replacing.

The wiring is quite simple on an RT. From battery, to switch, via a fuse, to item to be turned on or off. No interlocks or fiddly bits.

My bus number (if any): RML2532

Shiney works for me if you can find it. Stuck together? Well, please let me know if you find it.

I have continuity through both indicator fuses. When I flick the switch, I have 24V past one of the fuses and nothing past the other. Just one of many challenges. But I want to work out where the relay comes into play as well. Post-fuse? Is there a relay for the left indicator and one for the right or is it a shared or combined relay? Will one channel not working affect the other?

My bus number (if any): RT3316

RT indicators will be wired with the 12 volt bulbs in series. There is a moving track inside the turret on top of each ear which will break electrical contact when the ear is knocked round. While neither of these necessarily has any relevance to your faults, not realising these facts can waste an enormous amount of time fault finding.

Most RTs were retrofitted with flashing indicators. So the wiring is independent of the main wiring for lighting and the rest of the bus. Heater is the same. Both later additions.

But the insulation on the 3 RTs I've seen over the last 12 years has all been perished and hopeless for reliable use.

Better to renew all the wiring. Check the pigs ear contacts which wear out ( You can make new ones easily from a tin can lid and a pair of good tin snips )

Just feed and duplicate all the wiring and put ident sleeving on them for future reference.

It will make a huge difference.

You will probably find most of the RT wiring is a bit time worn but it is as easy as a Morris Minor to rewire and done well will make such a difference.

Most RTs were retrofitted with flashing indicators. So the wiring is independent of the main wiring for lighting and the rest of the bus. Heater is the same. Both later additions.

But the insulation on the 3 RTs I've seen over the last 12 years has all been perished and hopeless for reliable use.

Better to renew all the wiring. Check the pigs ear contacts which wear out ( You can make new ones easily from a tin can lid and a pair of good tin snips )

Just feed and duplicate all the wiring and put ident sleeving on them for future reference.

It will make a huge difference.

You will probably find most of the RT wiring is a bit time worn but it is as easy as a Morris Minor to rewire and done well, will make such a difference.

Thanks Jack and thanks everyone for your comments. I was sent a copy of the RT wiring diagram for which I am exceptionally grateful.

It has made all the difference as I was tracing the fuses where it said ‘indicators’. Now I realize that an indicator on an RT is actually a destination or route number box. The 'indicators' are 'trafficators' and come off of fuse 8 (shown on the RT as simply ‘auxillary’ – most likely because the flashing indicators came along later). So now I know that I have a short circuit on the front destination blind lights as well as the ‘trafficators’ and that I need to locate and troubleshoot the ‘interrupter unit’ which plays the role of the flasher unit or relay.

My bus has been re-wired. None of the wiring colours match what the diagram says, in fact it's mostly black and does have number idents. There may be corresponding number idents at the other end of some of the wires, but not the ones that I have come across so far. Thus, the idents may have meant something to the person who fitted them, but so far do not help me.

I am one step closer to fixing the indicators - whoops, I mean trafficators.

My bus number (if any): RT3316

Actually Steve you may have to double check a few things.
Firstly the date of the wiring diagram. There will be several updates from 1950 to 1973.

Secondly, you are right to describe the trafficators and indicators and yes the destination lights are described as indicators in most LT bus types.

Trafficators though, are not indicators. Many RTs did have trafficators fitted from new and also retro fitted to early RTs.

Just to confuse all and sundry, Trafficators were the name given to the semaphore type of indicator of which RTs had giant ones
On most RTs the housings remained. On the nearside window pillar and on the offside behind the drivers cab.

It may be that the wiring is tapped off from the original semaphores. Not being an electrician I don't think I ever knew what lay behind those housings. But I do remember that RT 990 at NB, a painter found the semaphores still intact behind blanking plates. That's the only time I ever saw them but maybe they were lurking on a great many more.

If the wiring diagram is genuinely one for semaphore trafficators, then there will not be an interrupter unit either fitted, nor on the diagram. As mentioned the trafficators were mounted on the lower deck front bulkhead where as the ears were mounted on the front corners at canopy level. The wiring route for the two would be different although it is conceivable that one could pick up from the other.

Thanks again - all comments appreciated. The diagram is not dated, but as it refers to LTE and shows trafficator ears, then I guess it must be pre-1962 and post whenever the ears started to be fitted, which I think was about 1959.

I haven't resolved the issue yet; I've ordered a new/better tester with some extension test leads. When they arrive, I will work through the various steps to troubleshoot the issue(s). I've also ordered a battery booster as the shorting out is killing a pair of good batteries! I can't run around to the isolator switch quickly enough!

My bus number (if any): RT3316

Steve I've sent you an E mail, look for it in your spam box!

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