TR4/4A headlight switch TR4a

[Richard_Brown]

It was working when I parked it last year. Now the switch will only work to flash the high beams but won't turn on the parking lamps or headlights. however the brake lights work when pressing the brakes so it seems power is getting to the lights.
any ideas?

 

[DNK]

Is the dip switch on the Floor? If it is ,check that.We just had that same issue.IIRC

 

[Richard_Brown]

the high beam/low beam switch? you think that could be causing the parking lights and headlights to not turn on ?

 

[DNK]

No , didn't read that
Richard do you have the Advance Electrical diagram

 

[Richard_Brown]

ahh, thanks.. I once had a color diagram in digital form and had a large printout of it but since has gone missing.

 

[DNK]

Interesting the way the tail lights get power
Brake light is not affiliated with the others
I would say there is something FUBAR with the switch. Take it apart and clean it. Watch those little springs
But I'm not 4 expert

 

[Richard_Brown]

Thank you, I will give that a try.

 

[DNK]

Richard , do you have Dan's schematics?

 

[Richard_Brown]

No I don't

 

[TR3driver]

The "flash to pass" position gets its power through a different path than the usual park/low/high positions do.

I would check the NU wire that (according to Dan's schematic) runs from the ignition switch to the headlight switch. One of the connections may have gone astray. Or in the ashtray, whatever

 

[Richard_Brown]

wow, thank you, that helps to know that the power is from another location for the flash.
I will check ignition to switch connection.

 

[TR3driver]

Not sure if this will be legible, but here is a snippet from Dan's schematic. The ignition switch is in the upper LH corner, and you can see the wire from it down to the headlight switch near the center. The top two contacts on the switch are the "flash to pass", which gets power from the fuse block.

 

[Richard_Brown]

Oh wow, I just found my full color PDF wire diagram for everything from tr2 to 4A,
happy to share if anyone would like a copy, its nice because it shows the wires in color.

Oh, never mind, I think this is Dans version.

 

[DNK]

Randall, I think he said the flash works ,so I think the N wire is fine. I still think it is in the switch.
Richard, try to fix your old one. New ones are not as nice

 

[TR3driver]

Yes, those are Dan's diagrams (which are still available for download from the Advance Auto Wire site). I snipped from a black/white version so it would be small enough to post above.

You could be right, Don, but I still think it makes sense to check the wire first. (NU from the ignition switch, not GN from the fuse block.) It's easier to check, and cheaper/less risky to fix.

 

[Richard_Brown]

Yes, those are Dan's diagrams (which are still available for download from the Advance Auto Wire site). I snipped from a black/white version so it would be small enough to post above.

You could be right, Don, but I still think it makes sense to check the wire first. (NU from the ignition switch, not GN from the fuse block.) It's easier to check, and cheaper/less risky to fix.

You were correct, NU wire on the ignition was loose, so that means the pass/flash gets power elsewhere. amazed all lamps work except the right parking lamp.


thank you

 

[Rrbbeerrttoo]

If I can ad a comment, just for information, the above electrical schematic is identical ( inclusive of the wire colors )to the schematics shown on my "TR4/A Workshop Manual by Kenneth Ball" and also the "Complete Official Triumph, Tr4 /A Handbook by Robert Bentley " .
My TR4A electrical circuits match exactly what is shown on these manuals.

 

[Rrbbeerrttoo]

My book schematic and my TR itself shows power to the flashing lights from the fuse block (A3/A4) thru wire L/G coming from connection 4 at the Ignition Switch . And this connection 4 at the ign. sw. is fed from wire NU at connection 1 in this ign. sw. , but only when the ignition switch is on engine run.
If only one flashing light is not working then the problem can only be a bad light bulb , a bad connection or open wire to that light, but only from the turn Signal Switch to that flashing light.
The above info. is true if the car wiring has not been modified.

 

[DNK]

Pass/flash ,doesn't it work if the car is off?

 

[TR3driver]

Nope, don't think so. Besides, it's really hard to pass someone with the engine turned off!