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Horn wire

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CJD

CJD

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Just hooked up the new wiring harness from Moss {post 60k). I noticed the original horn wires (brown/green and brown/black) are a heavier gage in the the original harness. I am guessing, but the originals look like 10 gage, vs. maybe 12 or 14 for the new wires.

Is the gage something that changed during production, or is the replacement harness just wrong?

Thanks,

John
 
Well, no takers there!

Has anyone ever put an ammeter on the horns to see how much they draw?

John
 
My 3 has the heavier wire. I don't know if it ever change. The bently manual shows how much amperage that each horn should draw. There are a couple of paragraph of pretty useful info.
 
Can't comment on the TR3 harness as mine is the Moss replacement and I have forgotten what the original looked like -- but on the TR4 (different horns but still no relay) the original (purple) wires are not huge -- perhaps 14g or possibly 12g.
 
Actually George, 14 or 12 is pretty big . In the scope of TR wire sizes
 
Yes John I questioned the same situation. The original stuff I think is about 10, but the English used/use a different system. The replacement harness I bought for my 61 was from the British wiring outfit (who I now have issues with) is perhaps a 12. The problem I saw was that the sub-harnesses I have from the horn to the plug are 10, so I think I would be gauging the wires backwards if that is electrically a valid theory. Like most of my writing, it is only theory. In the end, I left it that way because the scrap wire I have has the right color codes and it is 10. Again Imo, the system wirer lengths are short enough, so that I do not see a problem with mixing things up some.
 
That's a heck of a lot bigger than the 6 uses
 
Thanks to all...

Sp53, so I guess the smaller wires have worked with no problems. That gives me confidence nothing will melt down at least!

Eric, I see a lot of references to the Bentley manual. I'm new to the whole Triumph experience...I know it's a dumb question, but is that different than the Triumph manual...if so, what's the title so I can look for a copy...

John
 
There could be 1 difference in the smaller wires on the later cars. The 6 runs through a relay ,though both sides are the same size I think
 
John,

Bentley was one of the first publishers that reprinted the Triumph factory service manuals and, at least with the TR4/TR4A, with the owner's manual reprinted in the front as well.

Brooklands Books is also reprinting them now as well and appear to be more commonly found (Amazon for example).

Scott
 
Here is a link to a digital copy of the manual. Randall had posted this one a while back oodles of info and I read through it regularly. The other thing to obtain is the operators manual "practical hints" a google search will bring up a downloadable copy.
https://docs.google.com/leaf?id=0B2H2NJt...list&num=50
 
The horns draw current intermittently, while an ammeter usually averages to some extent. So the actual peak current is quite a bit higher than the ammeter (or fuse) would show. The fuse did get smaller on the later TR3A-B, but I don't know if the wire did.

Here's a copy of the later Practical Hints:
https://docs.google.com/viewer?a=v&p...yNzUw&hl=en

Working backwards from the fuse size and the British Wiring catalog, the earlier cars need 44 strand (which is about 12 AWG), later cars (with the "35 amp" horn fuse) need 28 strand (which is about 14 AWG).

Of course larger wire wouldn't hurt anything except profits, so that's still no proof that they changed.
 
Eric, I downloaded the Bentley manual...thanks! I'll look it over this week - It's always exciting getting new material to study! Randall, as always, great information. I'm satisfied the smaller wires will work just fine.

And thanks to all for the great info!

John
 
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