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MG MGA - wiring harness - modern replacement

Would something like this work in an MGA? I have to replace the whole thing anyway, and this is a lot cheaper and maybe better (?) easier (?) than replicating the vintage OEM solution...

Anyone tried this? Couldn't find it in the archives.

This is only one example - there are many variations on this theme for between $100 and $300 - various numbers of circuits, etc.

http://cgi.ebay.com/ebaymotors/T-4-Universal-14-Circuit-Wiring-Harness-NEW-Rat-Hot-Rod_W0QQitemZ250439872146QQcmdZViewItemQQptZMotors_Car_Truck_Parts_Accessories?hash=item3a4f612e92

Thanks.

JIM in NH
AJ Mail

Certainly looks interesting Jim....I'll be having a closer look myself.
Gary Lock

I used a harness like that (except it was Painless Wiring brand) to rewire my truck, and it worked quite well, but on an MGA? ick.
Del Rawlins

Better - Probably because of the multiple fused circuits

Easier - I really doubt it. You are going to have to measure, cut, and terminate each individual wire. With the clones of the original harness all you have to do is connect the wires.

Cheaper - Only if you don't count your time. You would spend so much more time I doubt it would be worth it.

Those kits appear to be just a fuse block with a lot of bulk wire and crimp connectors. You would basically have to design a complete wiring system and then build it.

If you ever needed to sell the car, it would certainly detract from the sales appeal and the selling price.


Jeff Schultz

This alternative is like starting from zero,looks like is for the basic circuits, just check your old harness count wires and lenghts of each one, and compare it with the material supplied with the kit offered in ebay,it is not enought, this will be a frustrating and expensive solution, better to save and use part of your original harness and replace the cables that are damaged.
R Garcia

Jim, I wouldn't think the kit comes with the correct colours for the standard harness, and as Jeff said, it would affect the value and appeal of the car if you ever tried to sell it.
If you have the old harness as a pattern you could make your own with the correct colours and then get it braided, we have "Autosparks" over here http://www.autosparks.co.uk/index.php?content_page=home who can supply the correct wire and the braiding service, maybe you have a similar company in The States but whether or not it would be cheaper than an "off the peg" harness I can't say.
Adding extra fuses to the standard harness is easy.
Lindsay.
Lindsay Sampford

I apologize to any purists that might be reading this - but I am going to continue to pursue this line of questioning until I have made my decision. Resale is not important to me - I want to drive it, and you can always keep the old parts.

Here is a much better source for a "modern" loom for MG's. Made for MGB's - at least the colors are correct! I have written them about whether they can offer anything for MGA or if the "early MGB" is suitable - but the early MGB seems pretty close, and I could use my existing harness as a supply of additional wire if needed. Unfortunately, at $480, it's still more than kind of expensive! The MGA PVC harness/loom from Moss is only $360 (but doesn't include the fuse block and relays).

http://www.advanceautowire.com

The manual for early MBG wiring instructions is online, and seems very clear with pictures. They also have a nifty wiring diagram for MGB (and Triumph) you can download for free. MGB at:

http://www.advanceautowire.com/mgb.pdf

They sell a "headlight relay kit" that you can use to graft into your old harness as well.

I wrote to both EZ-Wire and Painless wiring, and their custom kits are designed to fit "any vehicle" as long as it's Ford, Chrysler or GM based. They don't do British.
AJ Mail

I would replace with an original style wiring harness. These cars are going up in price all the time and original is almost always more desirable. The original wiring design is very good and with the original color code it is very easy to work on, especially for others. I have helped older members of our club with non-stock wiring that has not been well documented and it is not fun! If you keep it original it matches the wiring diagrams and anybody can help you. Just be sure to use new British spec fuses from Moss or other supplier. US fuses are rated differently.
Matt
M. H. Dabney

Count another vote for the factory wiring harness. There is nothing wrong with it except for a lack of fuses. If I remember, there are 3 or four circuits that come from the one fuse main fuse. This could easily be separated into separate fused circuits. Other unfused circuits can be easily converted to fused too.

I think most of those generic wiring looms will not accomodate the Lucas reguator box and certainly not the 1500 style brake/turn signal relay. Even if you don't use these archaeic devices, there will be more cuttin' & splicin' to do with the generic harness than if you try to add the fuses to the factory harness.

For the basic MGA circuits, you can do a lot worse than a fresh factory-style harness. Of course, if you are swapping out engines for one with EFI, adding electric door locks, windows and air conditioning, then you may want to rethink along the lines of the generic harnesses.
Chuck Schaefer

Advance Auto Wire just came out with an MGA version - should be on their site soon.

Nice guy and quick response to email.

I still haven't decided, though!

JIM in NH
AJ Mail

I think I have decided to purchase a replacement harness from Moss and then add additional fuses/relays where needed (in my opinion - and I know there are many opinions on this subject - whew...just got done reading the archives...). It's just too hard or too expensive to buy all the correct wire colors. I plan to make up my own fuse/relay panel for under the dash.

Two questions - 1. Does anyone have a printable 11 X 17 wiring diagram that is color coded? There is one on eBay that is for sale - but I am sure someone here knows of a source online. I can't find it. I have looked through Barney's pages and will definitely reference those as well, but I want one single one that I can print and mount on my garage door.

2. Has anyone who has made one of these fuse/relay subpanels have a diagram or good photo and part no's that they used? I have a 6-gang fuse box, and plan to add relays for the headlights and horn - and an extra for a possible future driving lamps/spotlight addition or electric fan addition; so that's 4 altogether. Fuses would be for radio, cigarette lighter, dash lights, fuel pump, etc.

Oops - third question. I need to find a domestic (US) source for the relays (Bosch? Other brand?) and (more difficult) the mountable relay bases or relay holders. Local parts stores only have the pigtail kind. I want this to at least look neat, and I want to be able to pull the relay out without unscrewing anything.

Much thanks for any help.

(Resto note: Floorboards are still only loosely fitted until all wiring is finished. I have shifted gears now and am repairing the body and fenders to get ready for paint. Rustoleum red rusty metal primer is great stuff! On all the areas you don't see when the car is assembled, I am brushing it on as I go around the car. The real advantage is that I don't have to set up the gun and hang all the plastic, etc. just to get an area primed, and brushing gives much better coverage than rattle-can primers.)

JIM in NH
AJ Mail

AJ-
If you've been reading archives, you probably know my feelings on all this, backed by a lot of experience.

Generic ones will drive you mad.

I recently got to observe a bunch of guys put an Advance Wiring harness in a TF1500, virtually identical to a MGA, what a circus! I had to tell them what went where, for about a year. I find the thing to be overdone to the point of silliness, though it is top quality, and the right colours, but not the right look. Looks like a power station gone bonkers. Wires too big, and too stiff, a generic relay fuse panel that puts most of that stuff in the wrong place, relays you don't need, etc. And no offense to Dan is meant, great guy, I just don't like the design, which is no improvement over a standard harness with a few judicious upgrades. And the connectors are not factory crimped, and since most people don't have a correct crimp tool and won't be bothered soldering ends on correctly, the whole thing isn't much good as usually installed.

Relays should be mounted in as straight & short a line as possible from power source to load. That means between the starter switch terminal and the lights, NOT under the dash. Fuses go as close as possible to the power source = near the starter switch for the relay power, and I fuse each relay separately. On all these cars, the most convenient point to wire the relays in is at the RHF where the standard light wires come out of the harness. You need about a foot of UW & UR to hook the relays up from the stock wires, several feet of Black, for grounds. Since these are only carrying control loads, you can use the too light wires from the HL pigtails, which you are going to replace. This is how Lindsay S and Neil F did it in the threads recently finished.

Power to the fusebox is browN, from there to the relay Purple; I mark multiple Purples with small rings of shrink tube: 1,2,3 etc. Or if you are running several to the same area, you can use good quality 14ga trailer cable, though the colours aren't correct, the protection is excellent. You need about 4-5 ft.

You could use several relays, all mounted at the front: HB, LB, Fog, Drive, Fan, Horn. That pretty well eats one fusebox. Run the wires now, even if you don't use them immediately.

The second fusebox goes where the stock one is, split the existing circuits up, and use one fuse for the fuel pump.

Correct relays & sockets from Daniel Stern Lighting. Be sure to get the correct double 87 terminal ones for things in pairs - like lights. I strongly recommend getting heavy duty pigtail sockets from Daniel as well, and replacing the pigtails to the HL with 14ga wire; takes about 8 feet of UW & UR, plus Black.

FRM
FR Millmore

What a great answer! I guess I'm ordering the Moss harness today. I found Dan's website and will send him an email. $75 for a headlamp, though?

JIM in NH
AJ Mail

AJ-
For your relay fuse block, you want a center stud fed one. Power comes in a single 10 ga lead from the start switch, goes out 6 separate fused feeds. Common "Buss part" at Advance Auto Parts etc.
For the other fuse box, try to find one with bridged feeds that you can cut to get various combos. You really want a browN, White, and a separate W (feeds) for the pump. If need be, you can do with two and jumper the pump fuse. I can figure this out but not now.
And, it's a good idea to fit one additional relay as an IGN. Under the dash and taking the load off the IGN switch. He make heater and wipers work good!

FRM
FR Millmore

Getting the quote from him now - will let you know what I end up with.

JIM
AJ Mail

This thread was discussed between 12/11/2009 and 18/11/2009

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