1999 Toyota Camry 10 amp Gauge fuse blowing

I got tricked about 2 years ago buying a used 1999 camry, they reset the engine lights and right before I got home the speedometer starting acting crazy and tranny slipping. Replaced the vehicle speed sensor which seemed to help. Speedometer would go wacky during heavy rain with puddles or if I ran the air. But car ran good.
3 days ago, I didnt really pay attention but I plugged a iphone charger into my cig lighter, I coulda swore I saw it light up but not 100%. But now I look at the charger and the nipple is missing, but the cig lighter still heats up but there are some burn marks on the inside of the lighter.
Problem im having is that the 10amp Gauge fuse keeps blowing, sometimes on startup, sometimes when I put in reverse, or sometimes when I drive about exactly a quarter mile. Seems to be that I can drive the quarter mile after the car has been sitting, but right after if I try to change the fuse it blows on startup. If its in between, the car will start but fuse will blow upon shifting from park.
There was kind of a loose bulb in the trunk light that I disconnected, looked thru all the wiring in the trunk and it looks fine. Disconnected and pulled fuses for the trunk and the Gauge fuse still blows. Disconnected an old alarm system and tried pulling various fuses still same thing.
Where would be next place to look. The wiring behind the Cig lighter that still works but possibly got shorted? Or the vehicle speed sensor that has been kinda wacky from time to time? Thanks!