TR2/3/3A Horn Replacement Wiring

[olarson]

I am replacing my 59 TR3’s horns. The horns I purchased have one black lead and one red lead. My new wiring harness has one brown/green wire and one brown/black wire for the horns. Anyone know which red and black wire connects to which of my two harness horn wires? Any help would be appreciated!!

 

[Sarastro]

The horns normally don't have a polarity, so it shouldn't matter as long as the horn's two wires are isolated from ground and there is no internal diode or anything weird like that. (Which is true of every replacement horn I've ever seen.)

That said, I'm a little concerned about the red and black wires, which imply a polarity, maybe because of an internal diode for reducing voltage spikes. To be safe, you could connect the red horn wire to the brown-green, which is the positive side.

Were there any instructions supplied with the horns?

 

[olarson]

The horns normally don't have a polarity, so it shouldn't matter as long as the horn's two wires are isolated from ground and there is no internal diode or anything weird like that. (Which is true of every replacement horn I've ever seen.)

That said, I'm a little concerned about the red and black wires, which imply a polarity, maybe because of an internal diode for reducing voltage spikes. To be safe, you could connect the red horn wire to the brown-green, which is the positive side.

Were there any instructions supplied with the horns?

The horns normally don't have a polarity, so it shouldn't matter as long as the horn's two wires are isolated from ground and there is no internal diode or anything weird like that. (Which is true of every replacement horn I've ever seen.)

That said, I'm a little concerned about the red and black wires, which imply a polarity, maybe because of an internal diode for reducing voltage spikes. To be safe, you could connect the red horn wire to the brown-green, which is the positive side.

Were there any instructions supplied with the horns?

Thanks for the quick reply. There were no instructions with the horns. I have had them for awhile and and just getting around to putting them in.

 

[CJD]

Red to brown/green and black to brown/black will work. That will maintain the polarity they seem to want, although +1 that it really shouldn't matter...unless one is also grounded to the chassis of the horn.

 

[olarson]

Thanks for the information. I will give it a try. I might have more questions later. Wiring is definitely not a strong suits.

 

[Fern]

If you’re upgrading the horns, it might be the right time to add a relay switch for them. Keeps the higher current out of the steering tube and horn button. Purchased it at Canadian Tire (Harbor Freight in the States) or any auto parts shop.

 

[olarson]

If you’re upgrading the horns, it might be the right time to add a relay switch for them. Keeps the higher current out of the steering tube and horn button. Purchased it at Canadian Tire (Harbor Freight in the States) or any auto parts shop.

Thanks for the advice. Where is the relay switch wired in? Is that a inline fuse? I am a real novice about wiring.

 

[Chipper]

I recently add a rely as Fern suggested. Also put on a separate fuse circuit and up sized the wire gauge. The horns are one of the largest power draws in the car.
If you wish to have the wires coming out of the horns match that of the original harness you can open the top cover by removing the screw. The cover will come right off if not rusted. You will find the wires are attached by bullet connectors. Just use some matching wire to the harness and rewire the leads.

This also is a good time to test the horns, clean contacts and adjust per manual spec. They are 65 years old and could use some cleaning and tune up. I gave mine a freak paint job while was at it. Looked for some pictures, but was unable to find.

Good luck
Honk honk