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TR2/3/3A TR3A wiring

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gene_s

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I am restoring a '59 TR3A that the previous owner had disassembled (I know, how dumb a purchase was that?), and am currently working on wiring--here are my questions:
1. The wiring diagram I have shows a ground wire inside the steering wheel hub. Since the horn is normally not grounded, what is?
2. I assume the steering wheel harness wires go through the steering shaft and exit where the union with the shaft to the steering box is (my car has the two-piece shaft), but how does that work when the steering wheel is turned?

HELP!!!

Gene
 
1) That's for the horn circuit. Power runs from the fuse box, through the horns and up the steering column to the switch. When that is connected to ground, by pressing the horn button, the circuit is completed and the horns sound.

2) There should be a tube running down the center of your steering column, called the stator tube. The wires run (very snugly) through that. At one end, the turn switch/horn button assembly slides onto that via a slot in the end of the stator tube and little "key" dimples in the tube on the switch assembly. At the front end, the tube is secured to the steering box by a compression fitting. This, a) seals the steering box, preventing the escape of oil and, b) prevents the stator tube from rotating. Neither the tube, nor the wires inside it rotate. The outside of the switch assembly doesn't rotate with the wheel, either. Only the internal plate rotates with the wheel, activating the self-canceling function of the turn signals.
 
The wiring diagram for sale at that link was really helpful. It's very big. I think the guy has two for TR3s. I think there was, at some point, a change in the color of a couple of wires.
Bob
 
There were actually several wiring variations, both in TR3 and in TR3A. Changes include things like the rheostat for the dash lights, in-line fuse for dash & tail lights, and whether a second green wire runs out to the wiper motor. Then there is the TR2 and early TR3 with the non-self parking wipers, where the switch controls power instead of ground. And of course the center brake light instead of two corner brake lights.
 
Randall, What's the difference between the twin green wire to the wiper motor (my old harness) and the single green wire set up (my new harness?)
 
bnw said:
Randall, What's the difference between the twin green wire to the wiper motor (my old harness) and the single green wire set up (my new harness?)
Click to expand...
On the harness with the two wires to the wiper motor, the second wire feeds power to the brake light switch. With the later harness, the brake light switch gets its power directly from the fuse block. The two are electrically equivalent (the wiper motor is wired to the same fuse), it's just that the wires don't follow the layout in the diagram.
 
martx-5 said:
They are reasonably accurate
Click to expand...
Reasonably, perhaps, but not 100%. For example, the factory overdrive harness from TS39781LO had the operating switch on the hot side of the relay coil, not between the coil and the lockout switches the way those diagrams show. TS39781LO also still had the switch for the panel lights, rather than the rheostat. And of course neither diagram shows the configuration with the brake light switch wired to the wiper motor.
 
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