I'm right there with you John.

Even the best quality wiring goes to hell in forty+ years.

I have already done most of the things you want to accomplish,

The wiring in my '64 PV544 had insulation that had hardened to the consistency of rock. It was very difficult to even strip a section to replace a connector.

The two worst areas in my car were the gang plug on the inner driver's fender. It had corroded and finally fell apart so the PO wrapped some tape around it to keep it together.

Since I anticipated adding a couple of more circuits to the front of the car (driving lights, etc.) I chose to replace the broken plug with a wiring block. It's kind of like a fuse box, but holds no fuses. You replace the spade terminals with the 'u' shaped ones or the ones with holes through them. Then the wires connect to the opposite terminals in the block. This allowed me to get rid of all the hardened wiring forward of the fuse block and replace it with heavier wire.

The wad of wiring in the driver's side of the trunk was the same kind of mess.
When I installed a wiring block back there it gave me a place to easily add on wires for trailer lights.

The rest of the wiring overall was in pretty good shape, so I left good enough alone.

When I got my PV it still had the incandescent headlights. You know, the ones BEFORE halogens. Driving home from San Francisco at night on I-5 I could barely see the road 30 feet in front of the car. As long as I ws in traffic it wasn't a problem, but when I got off the freeway and had to drive acroo country through farmlands, I had to slow down to about 30 MPH to be able to see the road. In other words, the headlights totally sucked.

One of my first upgrades was to buy a set of 7" glass headlight housings that would accept H4 bulbs. They're a 'diamond pattern' and probably aren't as efficient as a set of Hellas would be.

Anyway, I leapfrogged over Halogen and went straight to Xenon bulbs. THe benefit here is that the Xenon bulbs put out a whiter (bluish) light, much more of it, and use less electricity and run cooler to boot.

I also put H3 Xenon bulbs in my new driving lights.

All my headlights are run through relays. This reduces the amount of current going through the switches so they should last longer, and using a relay gives nearly full operating voltage to the lights. I used standard old-fashioned American horn relays. You can find these on hearly every car made before the 1990's. In appearance they're about 2 X 2-1/2 x 3 inches with three connectors and will have a flange on one side that lets you screw then onto the car. You'll usually find them mounted on the engine side of the firewall.

If you want to save a lot of trouble, just go to NAPA and ask for a horn relay for any American car from 1960 through 1980. Don't accept the little plug0in relays that fit into the fuse boxes on newer cars. Figure $3 -$9 each.

You can add more taillights if you want, but I found that by taking out the reflectors and cleaning and polishing them and installing new bulbs made mine nice and bright.

If you want to improve the rear lighting, try www.jcwhitney.com. They sell a bar with LEDs in it that you can mount inside the rear glass. They wire directly to your existing taillights and give you tail, stop and turn signal lights. They're designed for mounting at the rear of pickup beds, so there are two different lengths available; one for standard-size trucks and another for the small trucks.

If you're driving in stop-and-go traffic a lot you may benefit from adding an electric cooling fan. There are a ton of cheap ones on eBay. Look for the smaller ones so you can mount two, one on each side of the hood spring on the front side of the radiator.

I found that a good cooling system flush and a 6-blade stainless steel felx fan works fine for me, although I'm still considering an electric fan for backup on reaaly hot days.

I got a nice early stock Volvo AM/FM radio for my dash, but I installed my big JVC AM/FM/Cassette/12-CD/XM radio back under the dash. It came with a wireless remote, so it's a snap to use. The CD changer hangs from the underside of the rear package shelf in the trunk.

About the dimmer switch: To relocate it to the steering column you'd need to change out the whole column from the steering gear box back. While that's not as big a job as you'd think, it is a lot of trouble for not much gain. The floor switch you have now is another generic item. If it's giving you trouble, take it out and have our local parts store match it up to a new one.

I grew up with the dimmer on the floor, so it feels natural to me.

For a replacement turn signal switch assembly, keep an eye on eBay, I see them all the time. I'm sure someone here can tell you which years and models will fit. Also, there's the Volvo places that advertise here on the Brickboard. I'm sure they can get you a new one.

Addressing the brake light switch, you have tons of choices available, although I think GM used them the longest. Just be sure to mount it so you have enough space to make the height adjustment when you need to.

The stock switch is another generic item. If yours isn't working properly, take it to your parts guy.

Good luck and happy hunting!

Steve
California High Desert near Death Valley