I installed my Yaesu FT857 in the 2013 CMAX. The remote head got mounted on LIDO LM-300 gooseneck. As others have mentioned, mounting under the passenger side seat bolt was a problem that required some removal of the plastic around the bolt with a sharp knife. The next problem was power. I wanted to follow the radio manufacturers recommendation by installing directly to the battery. But the C-Max manual says install nothing on the battery because the battery is inaccessible and it would mess up charging measurements. The battery jump start post terminal block and the ground lug directly below it seems the best compromise. Then the problem becomes how to get through the firewall. There seems to be no clear space on the vertical part of the firewall. But after removing the two large plastic pieces that fit between the front of wind shield and the back of the hood, a space under the top of the dash becomes visible. Remove the driver side pillar cover and pull up the felt insulation there's a flat sheet metal area. I used a step drill to put in two 5/8 inch holes. Then one can reach a hand in from the engine side to install two rubber grommets. The I removed the cover over the terminal block under the jump start lug and installed a ring terminal connected to about 5 inches of #6 wire and a 50 Amp automotive fuse. A black #6 wire with ring terminal gets bolted to the ground on the frame under the jump start block. I used a coat hanger as a fish to go through the grommets and pull the wire into the passenger compartment. The two #6 wires then route under the plastic trim along the front and bottom of the door frame. There's quite a bit of room. The control wires run under the center console lip, under the front seat and into the rear seat bolt access area (remove the plastic cover) and then into the same wiring channel with the power wires. The control and power then runs into the rear vent compartment and out through the rear vent access panel. No problem with radio noise on receive using VHF, UHF or even Aircaft AM. No alternator whine (or digital switching equivalent) with that power connection approach. The antenna got drilled into the roof by accessing the sheet metal from behind the dome light. The first antenna should probably go into the rear dome light. I used the front dome light and it leaves the antenna tilted forward slightly, and it much more difficult to access the area between ceiling and sheet metal. Access to the roof at the rear dome light to run the antenna lead is achieved by pulling the rubber seal from the top of the rear hatch and then pulling down the ceiling a few inches. It appears to be held in place by a strong magnet. It's easy to route the coax into the left rear vent area to meet the power and control wires. All the wires exit through the lower vent access. I was tired by then and just put the radio into the left rear cargo net with the wires routed into the access panel behind the radio. It's quite practical, I may leave it there. This was the first time using a step drill and I will never go back, they produce a very clean round hole in sheet metal without grabbing. Next up is an HF whip and a second VHF antenna on the roof. jeff, wa1hco
