Good evening Ladies and Gentlemen, I am looking for some advice on our electrics.
Iveco engine RML 2505. When we turn on the isolator, the internal bell rings, not a full ring, if you press the bell button on the lower deck, nothing happens, upper deck works just fine. Started to happen towards the end of last summer, if she had been outside all night and the morning being damp, this would occur, didn’t stop her starting or operating. We have noticed this “problem” more now that she is stored for the winter, cold nights and again the damp is getting in.
Once the outside temperature warms up, or the bus has been running for some time, then everything begins to work as it should, the first bell to start working is normally the rope-pull one, followed by the conductor’s bell.
My old aircraft experience tells me to start working my way from the batteries checking all the connections, cleaning and reconnecting. I wondered if anyone had come across something like this before, is it a known fault or are we going in the right direction by cleaning the circuits?

My bus number (if any): RML 2505

The bell rope has shrunk with the damp. The shrinkage means the bell rope is pulled "on", hence the "half a ding" when the batteries are turned on. As the rope relaxes it will ding "off" as it releases. If you don't adress the issue quickly, the bell unit will overheat and possibly burn out. Upstairs works ok because upstairs is a buzzer on a different circuit.
Release the flap in the canopy above the bonnet to access the switch, ensure it isn't just a bit sticky, spray with WD40 to ensure free operation, and if neccessary slacken off the bell rope slightly. The "other end" of the bell rope is clearly visible. That should cure the problem.

My bus number (if any): RM531

Thanks for that Steve, makes perfect sense, will try it when I am down this week and post back

My bus number (if any): RML 2505