Help with superceded relay please?

[Jonathan Hanson]

Everyone,

I ordered a horn/start relay from The Roadster Factory to replace the one on the bottom of the first photo. What I got was the blue "superceded" version in the second photo . . . but there is no indication of where to hook up wires. The numbers on the old relay and the new one do not match. Any suggestions would be appreciated!

[baws]

Moss or Holden Vintage & Classic both stock the proper metal relay with connections that are the same as original and attach to body as the original.

[tr6harris]

Not sure where to start, so will throw out some thoughts.

First, so you know, the top relay is the Horn Relay, and the Bottom Relay is the Starter Relay (on the 74 and maybe 75). (And a benign 'Bulb Test' relay on the 76)

Not sure one superceeded relay model can replace both. That one might replace the horn relay, but the starter relay is special.

My first recommendation is to maybe return it and order one from Moss, who appears to have the original style.

You could try to use the replacement relay in the starter relay position, and I may have some notes, if Jim Herter does not come along who can likely answer off his head.

What year car? and why do you think the relay needs replacement?

Found some notes, likely by Jim Herter

Lastly, I am not seeing the color wires I would expect to a starter relay. Is your car possibly a 76, which had a 'bulb test' relay?

[RatRidgeRoadster]

If the blue relay is a Lucas SRB400 it should work as the BulbTest relay. But before you try it, it looks as if your existing relay is miswired. You have the much-discussed black/blue mystery wire that only some cars have connected to the relay. I notice a white/orange wire in the lower right corner of your picture that should be connected in place of the mystery wire.

Per the AAW diagram, the white/orange should be connected to the W1 terminal with one of the black wires connected to W2. It shouldn't matter how the last three wires are connected, but the diagram has the light green/white connected to C1, the other black connected to C2, and the purple/slate connected to C4.

If you do need to use the blue relay connect the white/orange to 86, one of the blacks to 85, and the last three however you want.

The reason it doesn't matter is when the relay is not energized all three wires are isolated and when the relay is made (energized) all three wires are connected together.

[Jonathan Hanson]

Thank you for the responses! Sorry I didn't identify the vehicle—a '76 TR6. I'm changing out relays because neither the horn nor the emergency flashers were working on the vehicle, and one wiring diagram I had showed the bottom relay as "starter, horn." The flashers are working now, probably because I replaced the flasher unit. The horn still does not work despite the new relay; however I've not yet checked the current at the horns and need to do that.

In the meantime, I've also installed a breakerless distributor and a Flamethrower coil. I was told I needed to bypass the ballasted coil wire, first by cutting and capping it at the coil, then moving the white and yellow wire from the starter relay to an ignition-controlled fuse terminal. This I did (see below) with the only wire that appeared close to white and yellow on the starter relay. However, when I turn the key to "on" now the starter immediately spins. I wonder if I need to move that wire back to the starter relay and simply run a dedicated wire from the fuse block to the coil? (I did re-gap the plugs.)

[tr6harris]

There is NO starter relay on the 76.....

[Jonathan Hanson]

Okaaaay . . . that would explain a lot I guess. What is the lower relay then please? "Bulb test?" What does it do?

Thank you again! I think I mistakenly followed coil rewiring instructions for a '74-75.

[poolboy]

You can read up on the bulb test relay in Chapter 21...usually with a specific reference to 76 models.

http://www.advanceautowire.com/tr2506/

[Jonathan Hanson]

Wow, I did not know about that resource. Thank you.

[RatRidgeRoadster]

Can you hear the horn relay click when you press the horn button? If it clicks, the problem is most likely down at the horns. If no click, take a screwdriver and short the W1 terminal (the one with the purple/black wire) to the grounded relay case to see if it clicks and if the horn blows. Post back with what you find.

Not that it matters now, but in my post above I misidentified terminal C4 as C3. Now fixed.

[RatRidgeRoadster]

I wonder if I need to move that wire back to the starter relay and simply run a dedicated wire from the fuse block to the coil?

Yes and yes. Connect the dedicated wire to the white wire side of the fusebox, so if the fuse happens to blow when driving on mountain roads at night (or any other time), the engine will continue to run.

[Jonathan Hanson]

Yes and yes. Connect the dedicated wire to the white wire side of the fusebox, so if the fuse happens to blow when driving on mountain roads at night (or any other time), the engine will continue to run.

Jim, do you mean I should connect it to the input side of the fuse?

[Jonathan Hanson]

Can you hear the horn relay click when you press the horn button? If it clicks, the problem is most likely down at the horns. If no click, take a screwdriver and short the W1 terminal (the one with the purple/black wire) to the grounded relay case to see if it clicks and if the horn blows. Post back with what you find.

Thanks for that; I will check in the morning. Neither the old now new relay clicks when I press the horn button.

[RatRidgeRoadster]

Jim, do you mean I should connect it to the input side of the fuse?

Yes, the white wire is switched on by the ignition switch and is unfused. If connected there, the engine will continue to run if the fuse blows.

[RatRidgeRoadster]

Neither the old now new relay clicks when I press the horn button.

We know you should have power on the purple wires on the relay because you said the hazard flashers are working (also on the purple circuit), so that would indicate that the relay is not seeing the ground from the horn button. Just to verify that and to verify that the relay is good, short out the W1 terminal as I mentioned in post # 10.

Assuming the relay is good, check to see that the front harness ground point and steering column grounds conform to what's shown in the linked pdf.

Let us know what you find.

Note: I could not upload the file as I did in the past. The link below is from the Ottawa Valley Triumph Club for the file that I gave permission to use. If your browser says it's a Potential Security Risk, you can safely ignore the warning.

http://www.ovtc.net/uploads/9/5/1/6/9516577/tr6_ground_points_hr.pdf