You can jump the trim solenoids to see if one or both are blown. I can't exactly tell you how but if you google it, it's quite easy. There's likely a YouTube video out there as well. If nothing happens then you might be in the same boat I was just in last week where I had to buy a new trim motor. My mercs a 1987 and I had to take the motor off with a cherry picker to get to the back screw to replace trim motor. Easy job, just a little time consuming. Before all this I'd also check you fluids as it could be that easy.
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