MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG TD TF 1500 - What gauge wire?

I have to do some cutting & splicing on the horns, does anyone know what gauge the wire out of the harness is?
Bob Dougherty

AWG 10/8/6, with the heavier of the three being the preferred. The horns draw a lot of current.
Cheers,
DW DuBois

Thanks Dave!
Bob Dougherty

I measured 11 Amps per horn.

Laurent.
LC Laurent31


Bob,

If you can, put them on a relay, they will sound fantastic and reduce draw on the system.

Jim
James Neel

Jim,

Do you have any details on fitting a rely to the horn circuit?

Jon
Jonathan Morgan

See the article Brake Light Relay in the Other Tech Articles in my Homepage at: http://homepages.donobi.net/sufuelpumps/ The article is for Brake light switch, but the relay will work just as well horn circuit.
Cheers,
DW DuBois

Yes I also add one relay to protect the poor little push switch. See also article in TT2 :

http://ttypes.org/ttt2/making-your-own-mg-td-wiring-loom
LC Laurent31

Sizes for "old fashioned" wire i.e. original T Series

8.75amp wire 14 strands each 0.30 mm dia O/D 2.7mm
17.5 28 0.30 3.4
27.5 44 0.30 4.2
35 65 0.30 5.1

Modern thin wall insulated wires.

11amp wire 16 strands each 0.20 mm dia O/D 1.6mm
16.5 32 0.20 1.95
25 28 0.30 2.55
33 44 0.30 3.2
39 56 0.30 3.5
50 84 0.30 4.1

If you are not bothered about originality you can upgrade your wiring using thin wall cable without increasing the overall size of the harness.


Jan T
J Targosz

Hi Jonathan,


For a TF

Cut the brown/black wire that goes from the switch to the horns.

Connect the cut end from the switch to terminal 86 of a standard automotive relay.

Connect the cut end from the horn(s) to relay terminal 87

Connect relay terminal 30 to a good earth

Splice into the brown/green wire going to the horn(s), this is the live supply, and connect to relay terminal 85

For a TD

Exactly the same but for brown/black read purple/black
and for brown/green read purple.

The horn is simpler than other electrical units since the switch (which is what you want to protect) is connected to earth and the horns are permanently live. All you have to do is run a wire from relay terminal 30 to earth. With other applications you need to run a heavy duty cable from a live source to the relay.


Good luck

Jan T
J Targosz

This thread was discussed between 15/05/2018 and 04/06/2018

MG TD TF 1500 index

This thread is from the archives. Join the live MG TD TF 1500 BBS now