For the pull down cord, I just used a very cheap micro switch. Normally open momentary contact. eBay
When I made the housing to hold my switches, which is pretty much just a folded over piece of sheet metal, I took a 4-5 inch long little piece of aluminum angle, maybe 3/8 of an inch by 3/8 of an inch by 1/8 thick, but you can use anything. I mounted the switch pointing up, put the angle on top of it with a pivot in the center of the bracket, and left it sticking out about an inch on the driver side, and put a chain on that. The little switch is strong enough to hold it open, you pull that chain to honk, you let it go and it pops back up. I just used beaded chain.
This might help too:
The trucks have a double roof. There’s the roof you see on the outside, and then there’s a second skin about a half inch or an inch inside of that which is actually what you touch from the inside above the headliner. I just used some super short, self drilling, self tapping screws to put a little angle on the front side and a little angle on the backside to hang my switch panel. Note a trick: I always use a little goop/E 6000 when I put in the screws. The screws hold tight, the glue keeps them from vibrating loose.
I did it so I can slide it in in the front, and then push it up in the back, and put a couple screws in it in front to hold it in place.
I ran a pretty stout wire from the battery, and one from the ignition, both fused 30A. Then I used a terminal strip, and tapped off that for the different lights and horns and whatever. If you look on eBay, the smaller illuminated switches on top are rated at 20A, and the bigger switches on the bottom are rated at 30A. They’re dirt cheap. On some of the heavier things. I also have an individual fuse.
When I made my panel and put in the switches, I put in four or five more than I needed for what I was doing at the moment. I ran the same number of extra wires from the roof down to inside the firewall. One of the problems is getting that many wires through the windshield molding and the molding on the A pillar. If you have a lot, you can run them to both the left side and to the right side to under the dashboard, and then route them wherever. I’ve done it many times before.
It looks like spaghetti, but if you do them one by one, it’s a very simple thing that you just do over and over. Beyond the shadow of a doubt, absolutely, use different color wires, and write down the color codes. I used an Excel spreadsheet to track all the terminals in the switch panel, track the wires where they came to the corner of the firewall, and then where the batteries ran behind my cab into my toolbox where I have my second battery. I printed it out which switch does what in a graphic and laminated it, and I keep that on the top side of my sun visor.
The switch panel has to be mounted pretty firmly to the roof to hang the CB off it. Even a little CB has a lot of momentum and tries to break loose as you go over bumps and go up and down. Note also, I ran the power to the CB from the wires I ran into the switch panel.
Finally, at the urging of some of the guys, I took a little piece of fabric backed vinyl and glued to the switch panel. I folded it over the edges and held them in place with those tiny plastic clamp things you get at Harbor Freight, and some binder clamps. Once it sets, you can cut a hole in the middle of the switch holes, and then just used a round file across the edges of the holes to cut the vinyl off even with the switch hole.
I like the CB and the switches up there, because it’s a quick flick of the eye to see them or see the knobs and meter on the CB, so you don’t have to take your eyes off the road. I hang my microphone off the right side of the CB: you can grab it and put it up and down without even thinking about it. If you install a mic clip, angle it upwards about 10° or the mic keeps popping loose when you hit bumps.
Important point, if you’re going to use a full-size radio like a 29 LTD, you definitely want the one that has the microphone coming out of the front and not out of the side.
Finally, the big radios I use interfered with the sunshades. On the 87, there’s a vinyl edge, sewn around the visor edge. I carefully used a razor blade under that vinyl to cut the threads and pull that edging back. Then I cut the visor shorter, and I glued the edge back with the goop/E 6000 using the little clip clamps. The 97 has the felt sunvisors. I just cut them where I needed them, and then I used a piece of the plastic wire loom to make a finished edge on the inside side. On both of them, that’s so I can fold the driver side down without moving anything. On the passenger side, you have to pull the mic to drop the visor down.
When it was all done, I took a couple pieces of cardboard and covered them with vinyl. I cut them to fit the sides of the bracket and the radio, and just used one of the screws from the radio to hold them in place. On the other one, I did the same thing, but I just put Velcro on the sides of the radio and the switch panel, and stuck the felt on there. That worked really well for some irregular surfaces.
