Refinish Dash
The dashboard was looking a little pitted and had a few dents. Also the ignition switch hole was mangled likely due to a previous owner not knowing how to remove the switch.

I started with a little glazing compound over the pitting and dings followed by progressively finer sanding, alternating coats of high build primer and wet sanding. This work included the A pillars too.
For the ignition switch hole, I straightened some metal and welded a little steel to fix the notch. I added a little glazing compound to smooth things out. Then more high build primer and wet sanding.
I finished the job with basic rattle can black semigloss. I know there are more concours compatible finishes but I dont really need that.
Wiring
I had already fixed the wiring harness issues a while back so there wasn't much to do. This harness was for a basic mid-year 65 Mustang so there were wires for the charge light, oil light, and single turn signal indicator in the cluster.
The cluster I have is a 66 round gauge style. Its in rough shape and the fuel gauge is fried. I gave it a basic cleaning and had to trim plastic off the bottom of the center circle to fit the straight dash metal -- the plastic bezel was already cracked so no biggie there.
I had another leftover donor harness from a 66 and swiped the left and right turn signals, and the oil gauge connectors. For the turn signals, I just spliced the bulb wires to an existing left and right signal wire.
Conveniently, the main power wire from the trunk passes right through the amp meter loop on its way to the fuse panel.
Another task before the goal of passing NY state inspection is the headliner. This has to go in before the windshield and rear glass.
I researched how most people install headliners and ended up using lots of small metal binder clips to keep the vinyl stretched and hold while the glue dries.
The headliner I purchased (TMI I think) came with a sound deadener/insulation pad and also bought the headliner glue. I was worried it would be a huge mess and end up loose and full of wrinkles but it turned out fine.
The key was to use lots of clips to hold it and stretch evenly and carefully.
I started by placing the bows in the car to make sure they are in the right order. Then sprayed adhesive on the mesh side of the insulation and on the roof underside. This holds it in place while installing the liner. Once tacky, pressed the insulation onto the roof underside, making sure nothing hangs down. Fatmat would probably have been nicer but I didnt have room in the budget.
I recommend screwing in the visor, mirror, and coat hook screws in now, before the liner, because it will be really hard to find the holes once the liner goes in.
Next I slid bows into the liner pockets and trimmed the excess pocket material since it would make the sides too bulky.
Installing the liner starts from the back. I hooked the rear most bow into the holes and made sure the liner was centered. This was followed by the wire hooks that hold the rearmost bow to the rear roof frame. These are really important to hold the bows as you pull from the front. The wire hooks pierce the vinyl pocket and clip onto rear the bow.
Next, I hooked in the remaining bows and pushed each of the bows up into place.
After that, the stretching starts from the front center, working out to the sides and placing clips as i go. Just make it very snug but not so tight as to pull the clips off or tearing stitches. Next is stretching from the back center outward then each of the sides.
It may be necessary to carefully snip excess material as you pull around the curves of the A pillars and window frames. Look for loose spots and wrinkles and adjust at clips as you go.
Once stretched, the gluing starts. Again from the front center, remove clips and spread glue on back of liner where it meets the frame and also apply to window frame. Slather it on consistently and allow it to get a little tacky for a few minutes before stretching and clipping again, it will bond immediately. I repeated on the back and sides and let it dry with clips in place and left clips on until the windshield and rear glass went in.
Be careful to stretch and snip as you gradually pull the liner tight around the A pillars and curves to make things neat and wrinkle free. This and the quarter vent area were the hard parts.
I highly recommend watching videos and reading further.
It's been a while since I updated my blog and much has been completed of the past 2 years.
Horn relay.
The original 65 Mustang harness was designed to send two 14 ga. wires up the column to the horn button switch. One wire with 12 volts and one returning from the switch to the horn.
Since I had installed a Flaming River steering column and a basic Grant steering wheel, I needed to wire in a relay to get the single wire horn button working. The concept is pretty simple. The horn switch turns the relay on with little current and the relay sends a higher current to the horns.
For a 65 Mustang wiring harness, there is a 14 gauge wire that comes from the headlight switch and is always hot. I connected this wire to pin 86 and 30 of the relay. The wire that sends 12 volts to the horns is a another 14 gauge wire, yellow with green stripe on my 65 harness.
I connected this wire to pin 87 of the relay. Lastly, I connected the black wire from the horn switch to pin 85 of the relay. When the horn is pressed, this wire will be grounded and turn the relay on which sends power to the horns.
Something to watch out for is that the relay may have an internal diode so connect the hot to pin 86. If you dont have a diode, its a good idea to add one to eliminate flyback voltage spike.