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MG MGB Technical - Fuse block upgrade?

I have scoured the archives and can't find a link(dead) for the fuse block upgrade to the new spade fuses Anyone have any new info?
Thanks Pat
patrick bailey

Patrick,

I just used a narva 4-slot blade fuse box (any equivelent e.g. Hella etc will suffice)...cheap, and a quick, easy replacement for the OE fusebox. The OE fuseblock (4 fuses) has some links between some of the input and output sides of the box, so just make sure you wire and connect it up properly...should take you less than an hour, including any new terminals you might need to wire, from start to finish.

I'm using 20A blades, which are similar to the original 17A/35A glass fuses.
Curtis Walker

I found a six-fuse blade type box that mounted on the same centres as the original four fuse-unit. The original box only has one link - between the top two fuses at the front, so the red/green wire can feed both fuses. The other end of those fuses feeds the parking lights, one fuse per side.
Paul Hunt 2

You might want to look at the kits from Advance Auto Wire, http://www.advanceautowire.com/. They may have something for you as the owner, Dan Masters, is a MG-TR enthusiast and has designed much of the offerings for our LBCs. You can also check out Painless Wiring, http://www.painlessperformance.com/index.asp and see what they have. Some auto chains also carry generic spade fuse blocks. The problem with most of those is that each fuse only has connections for one in and one out. Our OE fuse blocks often have multiple connections on either/both sides of the fuses used. I guess it mostly matters if the new block is being used to replace the OE block. If it is only for additional circuits, then this probably doesn't matter.

Bob Muenchausen

Can anyone explain what the various connections on the fusebox control(main items i.e. turn signals, etc.) along with the two line fuses that are located near the fusebox.
Duncan Armstrong

Patrick,

I got mine off of e-bay from a guy in Pennsylvania. When he makes these up he puts them on there to sell. Comes with instructions on how to change the wiring also form the 4 holder to the new 6 spade holder. Very simple and nice. Has a clear plastic cover. You can see what it loks like at: http://www.treasure-island-jewelers.com/1977mgbSupercharger.htm

Regards,

Ray

PS: When I get home I will look thru my paperwork to see if I can find any other information.
Ray 1977mgb

If you just want to change your fuse box, you can get them, in various configurations, from:

http://www.waytekwire.com

http://www.americanautowire.com

To identify the various connections to the fuse box, download the colorized wiring diagrams from

http://www.advanceautowire.com

Dan Masters

Pat. When buying generic fuse boxes from your local parts place you can wire them so all fuses are hot all the time or so the fuses are hot when the ignition in on. MGB OE fuse boxes have both. You could use a cheap generic fuse box and cut the center power strip and add a terminal on the end opposite the existing power terminal. That modification would allow you to wire with always hot and hot with ignition. If you only want four fuses Dan's auxiliary fuse panel will work well. It has two hot always fuses and two that switched by a relay.

Clifton
Clifton Gordon

Thanks guys for the info...i'll look into it I knew you guys would have it!!
Pat
patrick bailey

Duncan - there were boxes with 2 fuses originally and 4 fuses later on.

The bottom fuse in both is the purple circuit for things that need to be 'live' all the time like horns and courtesty lights. It is fed by the brown circuit.

The next fuse up in both is the green circuit for fused ignition stuff like turn signals, brake lights, reversing lights, and washers, wipers and heater fan in most years. It is fed by the white or white/brown circuit from the ignition switch or ignition relay respectively.

The top two fuses in the four-fuse box are for the parking lights, one fuse per side. There is only one wire (red/green) feeding the front of both these fuses, there is an internal link connecting them together. There are four red wires on the back of the two top fuses, one per corner.

In the last year of the 2-fuse box there were two in-line fuses, one for the front parking lights and one for the rear. Before that they were unfused like the headlights, which were never fused.

Around 1973 there was an in-line fuse (white/green to green/black) by the fusebox for the washers, wipers and heater fan as for a few years they were powered off the accessories position of the ignition switch and not the 'run' position.

The hazard flasher unit always had its own in-line fuse, conveniently placed behind the centre console!

77 and later model years had one (UK) or two (export) additional in-line fuses by the fusebox for separately fused branches of the green circuit, fed from the white/brown.

All the above are 17 amp rated, 35 amp blow.

There was also a 500mA in-line fuse for the North American sequential seat-belt control module, brown to brown/purple.
Paul Hunt 2

The stock fusebox works pretty well as long as it's in good shape. Is there a specific reason you need to upgrade?
Rob Edwards

This thread was discussed between 11/03/2006 and 12/03/2006

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.