Upgrading the fuse box

[alolympic]

Now, the standard fuse box on our cars is one of the most sub standard designs on the whole car, no surprise there.
So, as I wire up a new stereo, I thought it is as good a time as any to upgrade.
I have searched the Forum for some old threads to help but cannot come up with anything resembling a 'How To' guide.
Problem is, I'm an idiot in such matters so am reliant upon everyone's help in this area.
So, if anyone can contribute to creating a kind of 'How To' guide, I would be most grateful, and hopefully it will be useful for plenty of others too...(something I often wish we had more of on this Forum as I know so many of us ask the same questions over and over again).

Aims of the upgrade -
1. Split circuits across more fuses to reduce the chances of mass failure
2. Split circuits across more fuses to help fault diagnosis when a problem does occur
3. Fit a suitable fuse box that can fit in place of the existing box
4. Have space for spare fuses to enable any new circuits (like for the stereo) to be fused independently to keep subsequent wiring simple
5. Use reasonably priced parts so as not to break the bank

So, based on this, it comes down to the 'How'
Main decisions are;
- How many fuses seem appropriate?
- How to group the circuits sharing a fuse? by load would seem appropriate?
- Should all wires be fused?
- Should different fuse ratings be used for the different circuits?

I guess a good end result would be a diagram of a fuse box, showing which wires go where, and what fuses are suitable.

The choice of glass fuses or blade fuses seems to be an entirely personal one, so maybe we can leave that to one side.

I am copying the most relevant info that I have found from old threads which should help -

I bought this off ebay for just under £5 BIN (Incl P+P). Thought I'd post some pics in case anyone else wants one


The black cover on the left is obviously the standard cover and is there to give a size comparison


Just resting in position to show size.

It takes normal blade fuses.

The cover has a rubber sealing insert to it and seam a little flimsy but only if you're heavy handed.

Item was:-
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... &rd=1&rd=1

The circuits are probably goi to be:-

1, Permanent Live (No Lights)
2, Ignition Live (No Overdrive)
3, Overdrive
4, Dip lights
5, Main Beam
6, Stereo

....and some very useful info originally from Tinweevil, identifying which wires correspond to which circuit, with some ratings added by Straylight -

There are 6 wires on the right side of the box, anybody care to confirm or correct the following? Or add the ratings?

Purple 1:
- Hazard lights 21W x 4 = 84W = 7 Amps
- Cigarette lighter 50W max = 5 Amps (guessing it could be used to power a spotlight !)
- Clock bugger all
- Boot light 2.2 W = 0.18 Amps
- Courtesy light 5W = 0.42 Amps
Total 12.6 Amps

Purple 2:
- Horns ?
- Passing headlight flash 55W x 2 = 110W = 9.2 Amps

Green1:
- Reversing lights 21W x 2 = 42W
- Overdrive ?

Green 2:
- Windscreen wiper park function

Green 3:
- Windscreen wiper
- Windscreen washer
- Heated rear window
- Brake lights 21W x 2
- Blower
- Seatbelt warning
- Tachometer

Green 4:
- Voltage stabiliser which then does:
- Fuel gauge
- Temp gauge

So you could fuse the above groups by just moving wires at the fusebox. Then there is:

Unfused, supplied by a white wire on the left of the fusebox:
- Choke warning
- Handbrake warning
- Fuel warning
- Oil warning
- Brake balance warning
- Voltage gauge
- Ignition circuit

Which could be fused. Other white wire on the left is the feed from the ignition switch. Lastly there is:

Unfused, supplied from the splitter on the positive battery lead:
- All interior illumination
- All headlights
- All side lights
- Number plate illumination

None of my manuals show how fog lights are fed. If you want to break up these groups you need to find the splits in the loom or knit a new one. Draw lots of pictures with dimensions of the runs if you do please.

Tinweevil

Other peoples thoughts that may be relevant are -

"Indicators, wipers and overdrive are all worth seperating. The lights arent fused at all, which is crap" - Jonners

"Got seperate circuits for each of the purple wires and each of the green wires, spread some of that 35 amp load love around into smaller fuses. I'll get busy with the multimeter and work out exactly which parts of the purple and green circuit do what later. For now I can just put in 25 amp fuses" - Straylight

My first problem is that I am confused by the relationship between the wires on the left hand side of the box, and the wires on the right hand side - is the side of the box that each wire is connected relevant?

[Yellow Banana]

Not being electrically minded myself but I believe the wires leading to the fuse box from the left are the feed from the battery and those leaving from the right are the supply to whatever item(s) it feeds.
(Hope I've got this right Al!)

[alolympic]

Not being electrically minded myself but I believe the wires leading to the fuse box from the left are the feed from the battery and those leaving from the right are the supply to whatever item(s) it feeds.
(Hope I've got this right Al!)

Cool, makes sense.
So, based on that, it means that you need at least one wire either side of an individual fuse to make a circuit. Therefore, you can only split the the wires on the right hand side if there is a battery fed wire on the left hand side.
So, the number of wires on the left, determines the maximum number of separate wires you can have on the right?

[DavePoth]

Sort of - IIRC there are at least two connectors on the right side of the box for each battery wire. I should think (although I haven't looked at one) that a replacement fusebox will allow multiple fuses from the battery feed.

[Yellow Banana]

Is that a 12amp fuse you have in the lower part of your fuse box Al? Isn't that a bit low? I've got 35amp in both of mine (unless mine is wrong) but think that's what the manual says.

[Oli_88]

Is that a 12amp fuse you have in the lower part of your fuse box Al? Isn't that a bit low? I've got 35amp in both of mine (unless mine is wrong) but think that's what the manual says.

That's Sprintinbits car... Not Als.

[triple tango]

or go the whole hog;

[swifty]

When I was asking for advice on adding fog lights and extra gauges etc to my 2500s, the conscensus was that the existing loom was more or less at its limit without adding more gadgets. The suggestion was to route a new feed to/from the battery to effectively bypass the original loom and not put it under additional strain. This also means that these feeds can go through a new or separate fusebox.(giving the possibility of spare berths etc) Where possible the use of relays was recommended to take the strain off the loom as well. I would imagine much of the above would equally apply to the Dolly set-up

[triple tango]

Exactly my thoughts. All my original switches etc do is trip relays, so the original loom carries very little load.

[DazasDolly]

or go the whole hog;

I find this box with relays too complicated for the likes of a diy-a, like myself. But I do like Al's idea of the fusebox he shows and would consider doing this myself while i'm doing my TC up.

As when I opened my fusebox, my top fuse had tin foil around it. I also like Al, think it would be alot easier to identify faults, especially if we all put them in the same order, if and when the individual feels the need to change the fusebox.

All we need now is a wiring diagram.

Kind Regards

Darren

[1300dolly]

Im doing a similar thing to Roy on Sarahs car but playing with using a ford ecort fuse/relay box hiding behind the dash , im not to good at doing the talikng bit when it comes to wires though.

[DazasDolly]

Im doing a similar thing to Roy on Sarahs car but playing with using a ford ecort fuse/relay box hiding behind the dash , im not to good at doing the talikng bit when it comes to wires though.

Isn't that a bit dodgy using a ford one Justyn, I know in the 80's the ford fusebox was a right pain in the ass . And were a known trouble spot for ford.

Regards

Darren

[1300dolly]

The problem was with dampness/ corrosion getting to the back of the fuse box and a bit of 'cant be arsed to do it' attitude so if put in the right place it shouldn't be a problem as its a simple enough box to wire in, Im planning to put it inside the car.

[Jon Tilson]

Most of the answers to the original question are actually contained in that cut and paste bit of it....

Back top basics then. Dolomite wiring starts in 2 basic flavours....given that we all understand that the power source is the battery, which is kept charged by an alternator. So think of the battery alternator combo as the power station. From this comes a fat red cable that joins up with some less fat brown cables that come from the alternator plug and then go the live side of the fuse box and the ignition switch.

Battery and alternator are thus wired in parallel and the other side of the battery goes to the car body and engine via the fat earth cable. Where this is bolted to the body you will also see some more black wires which are earth returns for the headlights. There is a further earth return point on the opposite suspension turrnt for the heater and wipers etc.

From the ignition switch comes a fat white wire that goes to the live side of the fuse box too. So that gives you the 2 flavours....ignition fed and permanent live. On a dolomite you just get the 2 fuses one for each, which as I've said before and will say several times again is utterly crap. You also have the added complicating simplicity on the dolomite that none of the lights are fused, power to the light switch coming again from the ignition switch/loom via a brown wire. Then the side light circuits are all red and the headlights blue with tracers for main beam or not.

So a simple mod is to take that fuse box with more fuses and decide what circuit you want on each...I think its mostly in the cut and paste but I would seperate wipers, indicators, heater and overdrive onto independent fuses and leave the other 2 for whatever takes your fancy....like a radiator fan and maybe power to relays for the lights to give the column dip switch an easier life and cope with uprated bulbs.

Jonners

[1300dolly]

Can i just point out that whatever you decide to do thereare a few things that have to be on a battery feed so they work with the ignition off for the MOT
Hazzard lights
Horns
Sidelights