I have been investigating this as I am thinking about adding auxiliary to my 1816B. There are different types of auxiliary circuits and it appears that yours may be a diverted circuit. From what I have read, what happens is when the button in pushed, you hydraulics are diverted (typically from the bucket tilt) to you auxiliary. So, when the button is pushed your tilt controls would then work the auxiliary equipment instead of the tilt. When you release the button, you are back to operating your tilt. DISCLAIMER: This may not be the case but seems to be what you are describing. One way to check is to trace the wires back from the button, if it intercepts an actuated diverter valve on one of your circuits then this is most likely the case. You could then trace that hydraulic circuit and determine if it is on your tilt or lift. Good Luck, LM