Then don’t put them there. Seriously.
You’re doing the rewiring so you should make sure it’s safe. Since Ford didn’t put exhaust on the driver side, they put the brake plumbing and wiring over there.
You should always endeavor to keep keep the heat away from the other stuff. so that means either rerouting your exhaust, or relocating the brake plumbing and wiring.
Not always easy, or inexpensive to reroute the exhaust. But it is probably the main reason that many of us have gone back to single exhaust, or at least of keeping duals, running them both down the passenger side.
But if you have extra wire, it should be easy enough to put it on top of the frame instead.
Not so easy to redo the brake tubes unless you are at that stage in the build too?
This is excellent advice...
I would also add this one point. The factory under-body bronco wiring location is absurd. It is ONLY located on the frame because some joker on the design engineering team prioritized the gas gage over the lights. The factory wiring is set up as if the Bronco were to be sold as a Chassis-Cab configuration. You will notice that the frame harness plugs into the main harness at the firewall. It then attaches to the frame, FOLLOWING the brake and fuel lines, but not WITH them. The wiring harness has it's own special metal clips that drive and expand into the frame holes. (Impossible to re-use.) Then the harness runs to the rear fuel tank, and has a dedicated wire to the fuel sender. AFT of that, it has a 4 pin harness connector that plugs into the tail light harness. That tail light harness is secured to the body. There are no ground wires included in the chassis or tail light harness. The tail lights ground thru the body tub, and the fuel sender grounds thru the frame.
So yeah, if you were going to put a dump truck bed on your U14 pickup...you would be able to unplug the body from the chassis.
It is worth pointing out that the ONLY GROUND between the frame and anything else on a Bronco is the fuel sender ground. That's right. The only current carried on the frame of a Bronco is the gas tank sender. I have yet to find the ground wire that bonds the frame to the body. The negative battery cable runs from the post to the block. And there is a strap from the head to the firewall. And there is a wire from the block to the voltage regulator body. BUT... the ground path between the frame and the battery is: Throttle linkage, emergency brake cable, shift linkage, clutch linkage, and the steel brake line as a "maybe" but the early trucks were rubber isolated. How stupid is THAT???
My point being that there is no reliable ground for the frame, so if you are running an electric fuel pump...make sure you ground the frame to the body somewhere. (and of course, the body to the engine block.) Or carry a separate ground in your harness PLEASE.