Very common issue, my pedals do the same. If you look down there there is a cable that moves/spins to adjust the pedals. If you unhook the one going to the accelerator your brake should now move, you can use pliers to pinch the metal connector and remove it but I just did it by hand . If this doesn't work unhook the brake and then hook it back in. Basically the gear in your accelerator pedal is stripped and you will need to buy a new accelerator pedal assembly for it to work. Let me know if you figure out a way to fix it without replacing the whole accelerator assembly.
2005 Jeep Grand Cherokee 6.4L (The beast) (Fastest lifted WK) The Sparkly Build
2012 BMW X5 Turbo'ed (The b*tch)
1998 Jeep Grand Cherokee 4.0L (Ol' reliable)
The Following User Says Thank You to greenwayer For This Useful Post: