1.  Run sniff.exe with diablo2 running. 
2.  It will ask you for 4 values, one for each column in your belt. 
3.  Each value is what value your health will be allowed to drop to before it starts using potions from that column. 
4.  If autohealer kicks in it will print a small message in the window telling what your health was when potion was used and in what column. 

The best way to test if its working is to set the lower limit about 10 points below your max, then have a monster hit you and see if it uses the potion correctly. 
If you move charms or inventory items around as a test and have an object on your pointer, it will not work instantly, because you have to place the object down and then wait for another update from bnet telling the client what his health is before the program will catch it and then attempt a potion use again. 

Notes: 
It can't activate potions while your holding something on your pointer. 
The server only seems to send health information when your health changes (eg. monster hits you). 
I use it under WinME, It did not work correctly under Win2000. 
This is based on code from Mouspad and Nuttzy. 
