Welcome to our resource for MG Car Information.



TR parts and Triumph parts, TR bits, Triumph Car Spares and accessories are available for TR2, TR3, TR3A, TR4, TR4A, TR5, TR6, TR7, TR8, Spitfire and Stag and other TR models are available from British car spares and parts company LBCarCo.

Triumph TR3 - Wiring Harness Installation

Just wondering if anyone has ever installed a complete wiring harness themselves. Looks like my next winter job.
Are there any books on the subject? Any hints somewhere online?
'57 TR3

I am doing one right now myself, however it is not an original type. If you are intersted in doing something custom I might have something useful to say but if original I'm probably not the best person.
Have a look here:

and look under "Electrical"

J. S. Wallace

About a year ago I reinstalled the original wire harness in my 59 TR3A. All wires were in pretty good shape. Put some new tips on some of the wires where they connect to the tail/license lights. Took lots of pictures so I knew where the wire harness routed when I reinstalled it. Most of the original braid was missing so I wrapped the entire harness with vinyl tape. Replaced all the grommets where the harness went thru the firewall. I carefully identified the wires where they go to the front turn signals/park lights as the colors there were gone. I made sure the right fuses were in place in the fuse holder. Getting the wire harness up the tube to the horn and turn signal switch is a difficult task. Soap on the harness helped slide it through for me with a "fish" wire. Ground clips at the front wings are not available. I made some out of brass sheet. The connecting wires to the center instrument panel should be dressed so you can access the wing nuts to reinstall the panel. I also rewired the ammeter for negative ground when the panel was out-not orignal but necessary for most radio installations. I made sure I noted where the ground wires go when I removed them so they could be properly reinstalled as they are not shown on schematics. Most schematics for the wire harness also do not show the heater or washer. I made sure that all circuits were protected with fuses for the proper gage wire in a bundle so nothing will burn if a short occurs or normal currents flow.

I installed a new harness in a TR3B, which is the same harness for cars after Comm No. about 18000. After I laid it out it was fairly obvious where the various parts of the harness go--instrument panel, left side, right side, rear lights and fuel sender, etc. The wires are are color coded and with a schematic and color code it is fairly easy to follow. I had never before wired a car and it was OK, even fun, though it did take some time. The headlights and front parking/turn signal lamps have sub-harnesses. I was able to make these fom old harnesses. And yes, you should have one left over wirewhen you are finished. I will try to email or fax a copy of the schematic I used, if you think that might help you.
GG Krafft

I'm curious, which wire is leftover?

Jim...HJR...and Gary,
Thanks for that input. It all helped. It also is giving me a little more confidence for doing it myself. I did ask the local Brit garage for a quote if he did the wiring job and that's exactly what prompted me to do it myself.
Gary, sending me that schematic would surely be of help, I'm sure. My email is:

Thanks guys,

This thread was discussed between 31/07/2006 and 02/08/2006

Triumph TR3 index