T27 side light question

[Pedal Head]

Just pulled the lamp out & noticed it's a 5/21W E4, switching through the lights I only ever see the 5W filament on. Anyon know what purpose the bigger filament has?

[mrfixer]

Daytime Running Light I would think...

[Stivino]

Brake light if it's the rear?

[Pedal Head]

It's the daytime runing light on the front, I just can't figure out what the second filament is 

[mrfixer]

5W is sidelight

21W is DRL.....

[snowBALLs]

On my Yaris the DRL is bright on its own, when the side light is turned on the DRL becomes dim. My guess is 21w is the DRL on its own, once side light is on DRL becomes 5w. 

[Konrad C]

21 hours ago, Stivino said:

Brake light if it's the rear?

Unlike the T25 Mk2, T27 Mk3 rear lights are LED. I once helped my friend with his rear lights on his T25 Tourer, when he had a loose filament in the rear bulbs, causing intermittent instrument alerts. My T27 Tourer being the early version does not have DRL's and I recently replaced the capless 5w bulbs with LED's I retained from my previous Mk1 T22.