I have to pull the heater core in my Sami. It looks like it is inclusive with the blower unit. Judging for the size and space issues it looks like I may have to pull the dashboard? Could someone please tell me (truthfully) That I am mistaken. I leave for work at 2:30am, drive about half and hour, and it is really getting quite cold out the freeway. 

yep dang near have 2 totally dis assemble whole interior why does it leak?is the thermo switch frozen like every zuk ive ever bought ?check this first and if its leaking try an egg.i know it sounds rediculous but it works no maybes here it does and it doesnt clog core or rad either ive done this not just heard about it soo.

Somewhere on the web is an article that shows you how to cut a hole in the side of the heater unit to clear out all the rubbish that accumulates in there and stops the heater from working.

Edit: Try here:

http://www.izook.com/tech/samurai/body/heaterclean/heaterclean.htm

The Thermo switch is quite frozen. It is just frozen open, so the heater should still work. At least it did all summer long. I have fixed it twice now. It just refreezes. When I didn't need it.  It looks like drilling that hole will be my next task. The heater core doesn't appear to be leaking. Though occasionally I thought that I have seen some telltale vapors on the glass when I first turned on the defrost.

I have had to use that egg trick before. Strange, but it does work.

I have to repair a broke tab on the radiator anyway. Might as well do it all at once. 

def. drill the hole forst and check. I couldn't beleive how plugged mine was! It had a good 1/2" of pine needles/leaves/hardpacked dirt on top of the heater core!

If you duct tape a piece of flexible tubing to an air nozzle you can stick it up from the bottom ducts and blow any stuff lodged int he core loose while you use the shop vac to suck it up.

After that my heater worked better than new! (I say that cause I don't know what new would be like!  )

There a way similiar to clear out a trackkick heater box?  I can hear leaves rattling around.

Looks like that is what I will due this weekend.

Thanks for all the info.