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TR2/3/3A Rewiring a 60 TR3


Darth Vader
Afternoon all:

The body is almost ready for the final finish and will be coming off the frame. I will be getting the frame back and I am wondering how much of the wiring I should or could do, before the body goes back on? I have a new main harness and all of the necessary sub harnesses. I know that some of the wires hook to the frame and I have some nifty colored wiring charts but it doesn't go into the needed information as to what gets hooked to what and where. I suppose after I start it may become apparent as to where it all goes, HOWEVER, I have piddled with old cars long enough to know that there may be some info out there that I can't live without. So having said all of that, Any info would be greatly appreciated.

Thanks, Tinkerman


Jedi Knight

The only wire I can think of that hooks directly to the TR3 frame is the engine ground strap. I think that is attached at the left motor mount to engine mount plate and probably should be in place prior to body install. All other connections are made to the engine, dash, or body components. If I understand your question correctly. I wouldn't want the wiring in my way until after the body is mounted on the frame but that's just me. I guess what you can install and hook up depends on what is still mounted on the body, headlights, taillights, dash lights, dash electrical controls, fuse panel, regulator control box, wipers, etc? Nothing worse than having wires drop across a frame while mounting a body or having to lift the body twice to move them. I would try and have exhaust mufflers, frame mounted brake lines, and fuel lines in place though.

Lou Metelko

Jedi Trainee

There is no wiring harness replacement that can even be started without the body in place on a side screen car. The best advice is to make an enlargement of the late 3A wiring schematic in the owner's manual. Make the enlargement at least 2'X 3', get it laminated and put on poster board. Neat for reading small letters on the schematic and hanging in the garage for future reference.

Lou Metelko
Auburn, Indiana


Luke Skywalker
Wiring can be one of the most frustrating and intimidating parts of a restoration. Fortunately, most of us don't have to contend with lots of circuits for power accessories, etc. in our cars.

My siggestion is to do as Lou said...get a good color coded (if possible) diagram, blow it up and keep it handy.

Then do one circuit at a time, planning the route for the wires and loosly securing them in place until you finish the job.

Then look for possible pinch points, places the wires could chafe, etc. Then secure all the wires, tape those as required and you will be done.

I've done several hot rods using universal wiring kits...some kits are better than others but they all require patience and planning.

Do that and all will be well.

Geo Hahn

Country flag
Thw wiring loom for a TR3A is a very straight forward installation, if... you have the right harness for your car and you have the right wiring diagram for it too.

I did a cardboard mock-up of the center panel and left side of the dash to sort out the various small bits that aren't part of the main harness (dash lights, grounds, etc) that made transfering it the the real center panel very easy.


Not sure is the TR3 uses the same bullet connectors as the my TR6. If it does, call British Wiring and order their bullet connector plier. A great tool to make up the perfect bullet connector. Plus, I crimped and soldered all my connectors. And turn the bullet in the tube a few times for the ultimate connection. Crimp and solder, crimp and solder. You can't go wrong.

Actually, to me, wiring is the most pleasurable part of the restoration. Especially if you have a perfect wiring diagram and a good harness. You do have a harness, right. You are not making your own?


Jedi Hopeful
I agree with having the bullet connectors there. Also when ordering the bullets buy the correct fuses and plenty of the single and double unions for the bullets. British Wiring has the best pricing from what I remember. Also a Heat Gun and good set of crimping pliers and wire strippers. I would also get shrink tube to use with the heat gun to bullet proof some of the connections that you install on the wire harness. Especially ones like the Brake Switch. If this is a driven/drivers car make the wiring reliable and follow the previous advise above, but make it a fun project because wiring a TR3 requires stripping and prepping wire and is not a straight forward snap together harness.
Good Luck.


Jedi Warrior
Country flag
I'm almost done wiring my TR4 now and was in the same situation a week or two ago as you (considering having someone else do it for me). It's actually gone very well with very few gliches. I've asked a number of times to get pictures from other forum members and after I've been sent the pictures I realized that the information was on the wiring chart all along.


Jedi Knight
The most important advise I can give is to NOT ever disconect a wire untill you are putting in the new one.How you ask??you must cut up the old harness6 or 8 inches from every gage or switch leaving a nicely coded wire to lead you home later.No doubt there will be a few wires that the PO has repalced with red or pink, but the process of elemination will save you here. If 90% is right then only 10% can be goofy.
MD(mad dog)
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