K1 Vehicle Prior Depreciation—Converting to Income on Trade-in?

I have a vehicle that was put into service for my business in 2004 and was traded in for a new business vehicle in 2019.

 

I'm having a hard time with TurboTax and am wondering if this trade-in should be recorded as a sale or as a conversion.

 

When I enter it as a sale as part of my K1 (a sale for under 1K) it increases my income over 12K as a sale of business property. The trade-in value was just over 1K and business percentage ~50%.

 

When I enter it as converting to non-business use, there is no income increase, obviously, and this has a large effect on my taxes.

 

Should the prior depreciation of the vehicle (it was probably fully depreciated over the course of all of these years) be counted as income when I trade it in? At a loss and this doesn't make sense to me.