Power Trim/Tilt issue

The power trim on my 2000 40ELPTO will sometimes not lower, no matter whether using the dash switch or the switch on the motor cowl. When it doesn't lower, I can usually get it to work by touching the ignition. There's no clicking, just no response when hitting the down switch. My test light shows power going to the trim/tilt motor when the down switch is pressed, so the problem seems to be within the motor itself. Are there any serviceable components inside the motor or does the whole unit (part # 827675A1) have to be replaced? If replaced, has anyone had experience with any aftermarket units? Amazon lists several in the $100-$150 range, as opposed to the Mercury unit at about $450, so it's pretty tempting to try one. Thanks for any help.
Roger

I don't have a 40 so this is speculation but probably accurate. You may have a pair of identical relays for your trim drive. Blue is up and green is down (on mine) for the wiring to determine which is which. Swap relays and see if UP starts doing what Down was doing. If so, you found your smokinig gun. Other thing is to take your relays out and reseat them and any electrical connections to the PTT unit. Corrosion could have built up causing intermittent operation.