I installed a new stereo to my 67 400 convertible and left the wires hanging to test before I secured them neatly up under the dash. Everything was working perfectly. When I started securing the older wires under the dash I kept blowing the 20 Amp fuse for the Hazard/lighter/clock circuit. I totally isolated and disconnected all the new stereo wiring from the fuse block block and still I blow these 20 amp fuses. After looking around and testing with a multi-meter for 4-6 hours I could not find the problem, but I did find that over the years prior to me owning this car there had been some wiring modifications. So I figured it was time to replace the whole system.

So my questions are, has anyone totally replaced their wiring completely? Who has the best quality to get a kit from? And is it better to have an automotive electrician wire it in verses someone who has not done this type of extensive work before (like me)?

All other systems including the power top and electric windows operate normally.

thanks for your suggestions.

I'd check the lighter (orange) wire in the area you were working. Perhaps it got pinched or grounded somewhere.....

My wiring is 42 years old, I spent some time refurbishing and rewrapping it on the bench while restoring the car from the ground up.., but the wires were pliable and had never been cut in to except one spot which I shrink wrapped after soldering together...Everything works although I did have to run a new temp wire; and a new ignition wire due to Pertronix Ignition.

I replaced every single wiring harness in my car. While I got most of them from Classic Industries, I also got a couple of them from Ames. I believe they are all from M&H Wiring anyway.

The problem with CI (and why I went to them at first) was that I THOUGHT wiring harnesses would qualify for discounts. They don't.

With the right wiring (like the harnesses from M&H Electrical http://wiringharness.com ) you do not need ANY prior experience to rewire the entire car. You can also buy only the harness segments you need (forward lamp harness, engine harness, dash harness, tail lamp harness, and each of the accessory harnesses).

You do need a camera to document the routing, and masking tape to mark where the old connectors attach. I use paper tags with strings on the new harness and mark them the same as the old, as they remove easily with no residue.

With care and patience you can undo the sins of previous owners and repair your existing harness. Be sure to do it properly, and insulate and tie down the wires well. If the fuse block fuseholders are brittle or badly corroded, or if the wiring is stiff and the insulation brittle, replace it all.

We used American Auto Wire and replaced every single wire in the car with their kit, about $485. Another $70 or so for the power top wiring. So for less than $600 all new wiring. We had never wired a car before and was pretty staright forward with good instructions. The best part was connecting the battery and every sigle thing worked. I would highly recommend them.
We noticed a lot of the original wires throughout the car were brittle, cracked and corroded. After so many years of use it just makes sense to replace all old with new. JMO

I also am installing an american autowire kit. I did the research and is by far the best deal out there. All of the wires are individually labeled and there is individual wiring diagrams so you cant mess anything up. The kit also comes with many sockets including the park/turn lamp pigtails. Overall it is a very complete kit. I would hang on to your old harness because you will need to swap some connectors and it is good to have it for a reference. You should be able to do it yourself if you are somewhat mechanically inclined. I am an Automotive instructor but I am having my students install it with some supervision. They seem to be having no problems with it. Get yourself a good pair of wire crimpers and have fun. I bought it here. Free shipping http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=280402694943

American Autowire is a "some assembly required" solution. M & H is 100% complete and identical to factory in fit and appearance, it's literally plug and play, just put bulbs and fuses in the sockets and plug in the switches and connectors and it's up and running. You REALLY can't mess anything up, every wire terminates in a factory connector and the harness is custom built for your exact factory configuration, just like the GM parts bins along the assembly line had different harness codes for different option builds.

If you are planning for a concours restoration, consider the appearance. If you plan to add a lot of power accessories and assembly doesn't phase you, then you might want to put together your own harnesses.

M&H is considerably more expensive than AAW. I like that the wires are unbroken between endpoints.

How hard is it to re-wire a car that is already put together? I could see it being easy during the restoration process, but to do it on a complete car would seem to be a huge PIA.

Ive done multiple cars, and its not as bad as you think if you have a lot of patience, and have things appropriately disassembled. Removal of dash, kick panels, rocker sill, rear seat, etc, etc. . can make things go a lot faster. Take a ton of pics as you go through the process, and as noted, mark with masking tape what wire goes to what connector..and then mark on the dash, the firewall, along the rocker sill channel, etc, where things connect. Its obviously easiest is you can lay out the old wire harness with the new, and can swap out, swap in. If swapping in a used original harness, make sure to clean all connections, check all bulbs, etc.

Vikki is right, the American kit requires you to cut your wires to length and solder your connections. This does allow you to custom fit everything but is labor intensive. I found it satisfying and relaxing. In hindsight, completely wiring a car was relatively straight forward and simple. However, it was challenging at the time learning where everything went and how it worked. Rewiring a fully assembled car will take more time but if you break it down by rear harness, dash harness and engine compartment and set a goal to just complete one component at a time, you should be able to complete it in a few weekends.

The only areas that will present difficulty in a fully assembled car are dome light (headliner), power windows, power seat, power top, door jamb switches (kick panel).

The dome lamp harness is clipped to the roof rail with plastic clips, so you cannot just pull the old wire and fish the new one back. Well, you can, but you'll likely see the wire laying on top of the headliner.

To do the rear body harness, just remove the left kick panel, door sill trim plate, galvanized wire guards (pull back the edge of the carpet), rear seat, and rear quarter inner trim. The harness can be pulled out and fished back through without much difficulty.

Thanks to all for the very informative info. It will definitely help me narrow down the list of sources to purchase from. As with everything in life, it's a new learning experience. Thanks again to those who posted the responses. They are indeed helpful.

Bill