That is weird. My 99 SE just stopped running a few nights ago when the heater was turned on. Can't get the car to start for nothing. But my rear defog and radio won't turn off even with key out of the ignition. But I have no power to windows locks or wipers. Let me know if you figure it out. Sounds similar to what my car was doing.

i noticed that the 4th grid in the drivers side did not defog its line across,when i checked it with ohms meter there was no break in that grid,could that do it?

you have a bunch of parallel grids, you are going to measure through the others with the meter

i put it on vert one then one the horiz ones and got 2.4 volts on the 4th one i got 2.9 volts...

ok i did test light and i get 14 volts on drivers side and voltage dropps off going to the pass side and nothing on the end.have 1 grid not working but i dont see where the break is...they all measure the same.

If you are getting 14v when testing from wide/parallel side bus bar, then you should be able to move one lead of the multimeter towards the center of the parallel line, you should see the voltage drop by about half, so around 7v.
If you drag one to the center, or close to it, and see it shoot back to 14v, then the break is in-between your two multimeter leads.

Have you tried leaving the grid powered off, and using your multimeter set to ohms to try to chase the grids to see any big resistance changes?
I've never tested mine, but I'd be willing to test how the ohms change on my grid which all works fine.

no it seems like it just gets lower,if i do the grid that is bad from the drivers side i move the volt meter closer to the center it drops to 10 volts,but if i do the one above it that works the voltage is the same and the one above that..there it a certain point where the voltage it 10 and 1/4 inch over its 14.

I looked at it with a magnifing glass and cannot see a break in the line..

What year is the car?

2003 ssei