I want to check the fuses at the positive battery connection of my 1998 (first generation) Toyota RAV4. Visually, the 80a and 100a look fine, but the 50a has blue deposits and I can't tell if it's broken or not. No power is reaching my engine controller, and I've checked every other fuse and the relays, so I'd like to rule out a blown 50 amp fuse as a possible cause.
My problem is, I can't find how to remove them. Simply pulling with pliers doesn't work - first the clear plastic cover pops off, then the rest won't budge at all. It feels like I'll snap the fuses' plastic casing before they'll actually move. Curiously, wiggling it wiggles the plastic casing, but not the metal components inside the fuse. I can't find anything online.
There's a liftable panel on the terminal. Behind it are the connections for the three heavy duty wires. These don't seem to be related to the fuses and I can't see anything that looks like a clip (but I could be wrong).
Here's a photo of the three fuses in question. The 50A is the red one on the left. It looks like it should just pull out, but it won't budge: