I got honda odyssey the winsher pan is full but the lamp in front in my dash doesn't light off.It's always on.

It is very likely you have a stuck air temperature control blend door and or the blend door actuator has failed, since the dash must be removed to replace these parts you always do both.

park (tail, running) lights
there are 20 lamps in side and outside, are all 20 dead>
those lamps that glow HL switch 1st click is PARK
side lamps. dash lamps glow in park are they?
this answer , solves the who is bad.

as always, check all fuses first in both boxes
there may be a park relay./
alldata.com has the full schematic, if really curious. ...

close the doors and start engine
the cluster lamps all glow key on , not started engine,that is normal.
tell the full story.
i open car door, sit in drivers seat
close door.
then.... you see what?
then key on
see lamps glow, that is normal.
start engine, see them mostly out,normal.
the lights not out, now,are called warnings.

RTM? or Read the meticulously formulated manual RTMFM.
see here. read , the section on, before driving...
http://justgivemethedamnmanual.com/honda/honda-odyssey-owners-manuals/

the FSM covers these job, why not read that. or break lots of things
and plastic,

and step 1, DEFEAT AIRBAGS first or risk broken neck.
(death)
or login to alldata.com,

very complex and many trim levels and vast more compexity as options.
http://www.ebay.com/sch/i.html?_trksid=p2053587.m570.l1313.TR0.TRC0.XHonda+Odyssey+Service+Manual+2006&_nkw=Honda+Odyssey+Service+Manual+2006&_sacat=0&_from=R40

is the odometer VFD? (glow blue or green?)
know what that means? vacuum Florescence display>?
if yes, its NOT a lamp.
i looked in the online and it only shows a dash brain, controller.
in newer cars, there are no user servicable parts there.
on my 08 it has all LED and VFD. (zero lamps like in olden days)
i hope yours is just a lamp but i bet not.
check the FSM for full facts here.

check your brake fluid level also check to see if one of your bulbs are out

most likely the blower motor. not hard to replace on that vehicle. directly under passenger dash

using a test light check the fuses in the fuse panel then check for power and ground at the socket. if one is missing remove the socket and check for power and ground at the electrical connector. if you have both the socket is bad and needs replacing. if you missing one you will have to check that wire to find were the problem is and repair it.

A good indication of a blown fuse,

replace the bulb on dash its burn

Check the lamps first to see if both are good, do a wiggle test to see if the lamp's socket is good(sometimes they get too hot and the contacts spread open). Next check fuses for the running lights and break lights. If the running lights work on the front but not on the back then its not a fuse its a ground issue. Use a stick or another person to depress the break pedal to check for power at the plug that goes to the stop/running light lamp.