Brake light not working

Bit of backstory, I was at a friends house last night when I wanted to light up something behind me. 
Put on my front brake and the rear brake light didn't light up, I tried the rear one too and no light again. I can't really remember when I last saw it working as it's something that you don't pay any attention to until it stops working. Is it likely to be the bulb or something with the loom as I want a few suggestions before I have to remove my damd pannier rack and rear cowl...again... to find out.

Try the bulb for starters, flick the side light on and rotate the bulb 180 degrees (you'll have to hold it in because of the locking pin offset. Could be corrosion on the bulb contacts as well, all check-able in situ.

I changed my front brake line not so long ago, to wezmoto,(no sign of correct banjos used old ones) in process i disturbed the electric push on connectors at master cylinder, rear brake wasnt working  because of that:affraid:, if its bulb it just philips screwdriver to take lense off to get at bulb, shouldnt have to go near your rack?

I'll check the bulb tomorrow then. I replaced my front brake switch not too long back but when it wasn't working, the rear brake still activated the light. And it's coated in copper ease so it in theory won't get water in the connectors again

I'm going to bet that it's the bulb. Might not be, but...

What kind of rack do you have that means you can't get to the rear light?

It's a fehling/fivestars rack, it's mainly if I have to take the cowl off to get the the bullet connectors that could be a problem as it's a load of fafing about.

Just had a look at it now and it's a blown bulb. I didn't realise that there was 2 screws holding the lense cover on 

Just be carful not to over tighten them back on easy done then  crack