I can smell mold in my kitchen on the outside wall. This wall receives direct a.m. sun. Mold smell even comes through outlets, but there is no visible sign of mold on the sheetrock or under sink. Siding is hardiplank. There is a dw next to sink, but no signs of water (haven't pulled out dw to look behind. There are kitchen cabinets above & below countertop. How do I find mold w/o removing cabinets? I don't know where/how to start. thanks.

Wall tests are available from people that do mold testing. It is basicly the same as air testing but air is drawn through small holes in the wall. My bigger concern is if you smell mold you have it. However you must have moisture for it to develope. Is there leaks from plumbing you have not seen? What about bathroom above if there is one? Window frame leaking water? What about the basement or crawl below is there ponding water or seepage stains?
If you find the water you will find the mold.
You can also get a moisture meter and test the walls for elevated moisture readings. Numbers that begin to run in the high teens and above indicate a moisture issue thus mold. Remove the dishwasher and check.

No bathroom above. Under house is dry. There could be a window frame leaking (window is over sink and needs replacement b/c of window sill rotting. If the water comes from the window, is it going behind the siding? Would it be best to remove siding? It has been extremely dry in this area for months, so no recent rain. Humidity is also low. I'll try the dishwasher as well. thanks for the info on the wall test kit and numbers to look for.

I think you found the area of concern.
If the window frame is rotted its because of water. This same water is running down through the wall which could create the issue your having. Wet insulation can smell real bad if conditions are condusive to mold growth.
My suggestions is to repair the window sill. When installing the new window sill I would suggest a pan flashing under the window if it can be inserted without to much effort. It will prevent any future leaks from getting into the wall cavity. If the siding can be removed without to much difficulty I suggest this be done along with the sheet material behind. This will expose the back wall of the cabinets and cleanup can be done. Unless you rather take down your cabinets to fix any damage that may have happened which would be harder. Be sure to replace any exposed insulation if it appears to be wet or damp.