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1980 TR8 Horn not working - Relay good. Turn Sig. works.

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mypontiac Avatar
mypontiac Sean Cook
austin, TX, USA   USA
Hi Guys,

I have a 1980 TR8. Used to be my dad's car. All electrical works fine except for no horn and no fuel gauge.

I am currently looking to fix the horn issue as this will prevent me from passing the safety inspection.

I checked the relay (replaced it) and still no horn.

The turn signal arm is faulty as it rotates. Not sure it this affects the horn, but I am thinking it needs to be replaced. Turn signals work. Brights work.

My dad had purchased a new turn signal, but it is for the 75-79 TR8. Can this still be used?
Can I jump wires from the harness to see if horn sounds off?

Thanks for any suggestions.

Sean

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RossL Silver Member Ross LoMonaco
NJ, USA   USA
Did you check the fuse? Does the relay click when you press the horn control? You should be able to hear it or feel the relay click. This would test the horn control.

When I got my car both horns were bad. I connected a test light at the horn location and found I had power when I engaged the horn. Replaced both horns.

mypontiac Avatar
mypontiac Sean Cook
austin, TX, USA   USA
Hi Ross,

Good question. I looked at the fuses, but didn't find a bad one.

But you other question concerning the click, no I don't hear the relay click. This also led me to believe it may be the turn signal switch.
Could you hear the relay click when the horns were bad?

What would cause the relay not to get power?

Sean

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RossL Silver Member Ross LoMonaco
NJ, USA   USA
The relay gets power from the switch. The turn signals are separate from the horn. So just because the turn signals are working, that does not mean the horn switch is good.

Find the fuse for the horn and replace it, unless you checked it with a meter. Sometimes a fuse "looks" good when it's not working.

I could hear the relay click when the horns were bad. Some relays might not make much of a sound but if you put your finger on it you can feel it engage, if it's working.



Edited 1 time(s). Last edit at 2018-01-19 06:26 AM by RossL.

mypontiac Avatar
mypontiac Sean Cook
austin, TX, USA   USA
Does anyone know which fuse would be for the horn?

I found a typical fuse layout for a 79 TR8 and the horn is not identified.

Top Row Left to Right
1. Left Dipped Beam 10A
2. Ignition Switch Aux 15A
3. Left Main Beam 10A
4. Heater Blower 50A
5. Right Main Beam 10A
6. Right Dipped Beam 10A

Bottom Row Left to Right
7. A/C Fan 20A
8. Rear Defrost 15A
9. Battery Aux 50A
10. Right Side Lights 10A
11. Left Side Lights 10A
12. A/C Fan 20A

darrellwalker Darrell Walker
Vancouver, WA, USA   USA
1966 Triumph TR4A "Christy"
1981 Triumph TR8 "Kate"
This is from the 1980 carbed TR8s schematic at:

http://www.team.net/TR8/tr8cca/wedgelab/other/schematics/schematics.htm

It shows fuse 5-6 supplying power to the relay.

You can see what else is feed by that fuse.



Darrell Walker
66 TR4A IRS-SC CTC67956L
81 TR8 SATPZ458XBA406206
Vancouver, WA, USA


Attachments:
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Screen Shot 2018-01-19 at 9.54.02 AM.jpg

mypontiac Avatar
mypontiac Sean Cook
austin, TX, USA   USA
Hi Darrell,

Thanks for the link to the schematic!

Looks like the clock is powered through the same fuses and it works. Guess it is something else?

I see power from the relay to the buzzer unit. The buzzer does not go off. Could this be affecting the relay?


Thanks,

Sean



Edited 1 time(s). Last edit at 2018-01-19 02:42 PM by mypontiac.

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RossL Silver Member Ross LoMonaco
NJ, USA   USA
I would check the horn button/switch. Try removing it and jumping the purple and purple/black wires

Darth V8R Avatar
Darth V8R Vance Navarrette
Beaverton, OR, USA   USA
1980 Triumph TR8 "Wedgie"
In reply to # 1508324 by mypontiac Hi Guys,


The turn signal arm is faulty as it rotates. Not sure it this affects the horn, but I am thinking it needs to be replaced. Turn signals work. Brights work.

My dad had purchased a new turn signal, but it is for the 75-79 TR8. Can this still be used?
Can I jump wires from the harness to see if horn sounds off?

Sean

Sean:

Don't know if it can be used or not. It may be electrically compatible, but not mechanically compatible by virtue of a different pinout. So you might need to rearrange the wires.

What I do know is that the correct switch is available here. This a genuine new Lucas switch. They also stock a repro for less money, I think. People have complained on this forum about the reproductions, so buyer beware.

Your father probably purchased the switch he did because the big three only seem to stock the older design, so he went with what they had.

Cheers,

Vance



1980 Platinum Metallic TR8, navy blue interior
Bare metal respray, Crower cam, raised compression
ported heads, modified Zenith carbs, 0.060" overbore

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mypontiac Avatar
mypontiac Sean Cook
austin, TX, USA   USA
Hi Ross,

Thanks for the information on which wires to jump. I will do that tomorrow.

Hi Vance,

Thanks for the link on the Lucas turn signal. My dad actually bought two of the ones in the blue box. The stick is different than the one on the car due to the difference in year.

Is the plug on the correct switch male or female?

Sean

Darth V8R Avatar
Darth V8R Vance Navarrette
Beaverton, OR, USA   USA
1980 Triumph TR8 "Wedgie"
In reply to # 1508572 by mypontiac Hi Ross,

Thanks for the information on which wires to jump. I will do that tomorrow.

Hi Vance,

Thanks for the link on the Lucas turn signal. My dad actually bought two of the ones in the blue box. The stick is different than the one on the car due to the difference in year.

Is the plug on the correct switch male or female?

Sean

Male.

Vance



1980 Platinum Metallic TR8, navy blue interior
Bare metal respray, Crower cam, raised compression
ported heads, modified Zenith carbs, 0.060" overbore

mypontiac Avatar
mypontiac Sean Cook
austin, TX, USA   USA
Swapped out the horn/turn signal yesterday. Still no horn?

I am going to check the 5/6 fuse again. Just swap them out to be sure.
Also check power at the wire to the horn at the switch.

Can anyone recommend a good aftermarket horn?

I found this kit.

https://www.englishparts.com/products/gb/Triumph/1980/TR7/AIR-HORN-KIT--DUAL--COMPACT/5820959/545-085.html?partner=googlebase_adwords&kwd=&origin=pla&gclid=EAIaIQobChMI4uOuy6So2QIVzVx-Ch3wsAOFEAYYASABEgIel_D_BwE

I need to be able to pass inspection next month.

Sean

Darth V8R Avatar
Darth V8R Vance Navarrette
Beaverton, OR, USA   USA
1980 Triumph TR8 "Wedgie"
In reply to # 1513535 by mypontiac Swapped out the horn/turn signal yesterday. Still no horn?

I am going to check the 5/6 fuse again. Just swap them out to be sure.
Also check power at the wire to the horn at the switch.

Can anyone recommend a good aftermarket horn?

I need to be able to pass inspection next month.

Sean

British Parts NW sells a Lucas drop in kit for less money. Lucas Horns These guys are a pleasure to deal with if there are any questions or problems. NFI.

Unfortunately, the factory location for the horns puts them in harm's way; Low, under the car, constantly exposed to road spray and dirt. And given the unsophisticated electrical connectors on the horns, they expire rather readily.

Vance



1980 Platinum Metallic TR8, navy blue interior
Bare metal respray, Crower cam, raised compression
ported heads, modified Zenith carbs, 0.060" overbore

RossL Silver Member Ross LoMonaco
NJ, USA   USA
I used aftermarket horns from Autozone (hi/lo).

I used a test light on the connector that attaches to the horn under the front of the car. Both of my horns were dead when I bought the car.... The test light showed me the switch and the circuit were working fine.... Having two horns go bad may be unlikely but its possible.

mypontiac Avatar
mypontiac Sean Cook
austin, TX, USA   USA
Hi Vance,

Can you post a link to the horn kit?

I tried looking at the site, but it is elusive.

Thanks,

Sean



Edited 1 time(s). Last edit at 2018-02-15 12:22 PM by mypontiac.

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