To replace lamps the cluster must be removed.
The entire instrument cluster must be remove to replace lamps. If equiped with Electronic cluster, it might be better to take it to the dealer.
Remove the instrument cluster then replace the bulbs. = =
There is no separate switch for it. Pushing the light switch will defeat the dome and courtesy lamps.
daytime 'running' lamps/lights.
yes, there is a coating in the lamp, which contain mercury
A small amount of mercury is used in fluorescent lamps.
If you are referring to fluorescent and CFL lamps, it can never be totally eliminated. These are mercury vapor arc lamps using a phosphor to turn the UV to visible light. They have reduced the mercury dramatically, but it can't be totally eliminated. If all fluorescent and CFL lamps were banned and lighting was all converted to LED then use of mercury could be stopped. However most LED lamps cost at least ten times what CFL lamps cost.
Sodium and mercury are used in the majority of street lamps today.
Yes, you can definitely replace reflector lampes with LED reflector lamps. I got a Lighting Ever LED reflector before, so no problem I think.