Rewiring a 66 Mustang to get rid of the old 3 wire fuse box?

[Edz66Vert]

As the topic says, I want to rewire my 66 Mustang to get rid of the old 3 wire feed in fuse box.

(Apologies up front if this has been covered before, when I search for fuse box or fuse box nothing came up except 3 x 50 page project builds)

Why do i want to do it? The wiring under my dash is a bit of a mess as someone has hacked in and added and removed bits, my door switches don't work, I had to bodge in the wiring for the stereo and tacho and it worries me to rely on old glass fuses I can't easily buy when i can upgrade to a modern blade fuse block quite cheaply that gives me extra outputs for all the accessories I want to add.

I found a nifty 10 fuse block that has led's that light up for a blown fuse.


The other option is the standrad Narva 8 fuse block that has multiple inputs and outputs so could easily be wired into the standard 3 circuits by combining some inputs.

I don't want to buy a whole harness, my budget won't allow it at this stage and and I don't want to pull the whole car apart to install it either.

Anyone tried this before?

[Nuts]

That'll work fine. I like to protect the horn circuit with a relay as it is +12v constant. Also like to and a relays for hi and low beam. As you are adding fans I'd relay them as well. Make relays do the hard work, not the switches.

[nassi]

Plus one for the relays, if use a fused relay like this https://www.partsales.com/details/spare ... vAodmzYHUw
then it takes all the load off your original wiring.

I still use the old glass fuse box and if required solder some spade terminals to the old fuse and then connect a blade fuse. Sounds messy but in reality I have only ever had to do this once 30 years.

[boofhead]

When I did mine I used the second set up. Get them from jcar . Cut a wire crimp and put on the new box - relatively easy job.

[Edz66Vert]

quote="Nuts" That'll work fine. I like to protect the horn circuit with a relay as it is +12v constant. Also like to and a relays for hi and low beam. As you are adding fans I'd relay them as well. Make relays do the hard work, not the switches."

I've already wired in 7 relays for the Hi and Lo Quartz headlights, 2 for the LEDs, 1 for the air horn and 2 for the fan to split the 22 amp load as I had the single plug melt. Have NO and NC relays setup to turn the LED Lights off for night-time when the lights go on to meet the ADR's but seeing the number of late model cars that don't I may remove them when i rewire for the battery turn-around for the 24 " radiator install. I need to rationalise the relays as I may have to add more, so I will probably move them in behind the grill now I know how easy it is to remove it. It would be nice to mount them under the dash to tidy it all up but then I would have to run a lot of thick wires and that defeats the whole purpose of running relays.

Some of the relays I used are the fused ones you linked to Nassi, cool design, bought them on fleebay with plugs and wires for $1 each. Also bought a pre-wired Hi/Lo harness with headlight plugs and relays to update the headlight wiring for $12 which fitted well and simplified the wiring install. Great upgrade to give much brighter lights than standard and allows for Quartz Halogen headlights.


I think I'll just buy some fuse panels and have a go and take pics and notes to post to help others.

[Edz66Vert]

"boofhead" When I did mine I used the second set up. Get them from jcar . Cut a wire crimp and put on the new box - relatively easy job.[/quote]

Not sure what you mean there Boofhead? 2nd set? Cut a wire crimp and put on the new box?

I'll be removing the whole fusebox and upgrading it.

[boofhead]

There are 5 fuses in the early fuse box. The second pic of the blade fuse box is the one I used as it has 6 blade fuses available so your all good and have a spare. Pull the old box out look on the back cut a wire - crimp on a female terminal on the wire you just cut off the old box. Now insert onto one of the male terminals of the new fuse box. Then cut the wire from the other side of the glass fuse then crimp etc and install on the opposite side of the blade fuse terminal so your now finished the first of 5 fuses. Once you have done all 5 fuses throw the old fuse box away. Easy job - if you have been doing relays then this is easy.

Note: The first box pic is no good for this job. It uses a single input and many out. Good idea for some wiring set ups but not to replace the 65/66 factory fuse box. In combination with a relay feed it is great as a switched power source.

[Edz66Vert]

There are 5 fuses in the early fuse box. The second pic of the blade fuse box is the one I used as it has 6 blade fuses available so your all good and have a spare. Pull the old box out look on the back cut a wire - crimp on a female terminal on the wire you just cut off the old box. Now insert onto one of the male terminals of the new fuse box. Then cut the wire from the other side of the glass fuse then crimp etc and install on the opposite side of the blade fuse terminal so your now finished the first of 5 fuses. Once you have done all 5 fuses throw the old fuse box away. Easy job - if you have been doing relays then this is easy.

Note: The first box pic is no good for this job. It uses a single input and many out. Good idea for some wiring set ups but not to replace the 65/66 factory fuse box. In combination with a relay feed it is great as a switched power source.

I ordered both as they are cheap. The second will work as you say and will give me some extra connection points. I can add the first one in to provide a good source for extra power outputs to run an alarm, electric windows, etc, love the leds on it that light up if I blow a fuse.