I have Garmin GPSMAP 540 on the dash of my 31SS. Since I'm the only one that can see it, I'd like to add an external GPS speedo to the port side. It would run off the NMEA output wire. However, I can't figure out how to get the wire over to the other side. I don't want to break the seal around the headliner. Is there another way?

Sonic typically runs a pvc chase under the floor from the galley cabinet to the dash, I know this to be true on the 358 and up and pretty sure they do it on the 31 as well. You will have to reach into the bottom of the cabinet at the galley and pull the carpet back which is held in with spray contact. At the back side of the dash the the chase should enter in at the bottom of that cavity

Thanks, I'll check it out.

Plum, As Sonic Steve said there is a rigging tube running underneath the cabin door. You can see it if you look down through the dash access door above you toilet. If you take off the dash panel on the passenger side you'll be able to bring any wiring up through the cavity behind the dashboard cooler. Those rigging tubes make it so nice when you want to do upgrades! Steve

Yes, I dug into the boat tonight and found the pipe. It will be a challenge feeding the wires through, but I'll get it. I plan to mount the speedo and recall switch on the pass side dash panel.

I'm thinking about getting a new pass side dash panel while I'm at it, maybe in blue instead of white. Does anyone know what they cost?

We have been using a tinting process with paint and clear to do dash plates and panels. Find me a color blue you like, send me the panel and we can make it happen for you. We did this on our Sonic switch plates in red and they came out great.

Plum if you want to try this. In my 31SS I mounted the GPS pick-up under the dash. First I used tape to see if I had a good location. then I made a bracket under the dash it worked great. I just hate drilling holes in the boat if I don't have to.

Plum, Just use a electrical fishtape for running wires through the tubes. Steve

Oh, yea. That's what I plan to use. However, there's lots of hoses and wiring already in the PVC chase. It's pretty full.