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No headlights!


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I’ve had my 4a now for some 8 weeks and getting to know its quirks, loving it by the way.

however the electrics are something else…horn works sometimes but often not! The headlights will only work on full beam, no dipped lights at all! Lighting on the dash may as well not be there either.

it has been suggested that wd40 around the foot switch might clean up the contacts and give me my headlights back. Tried that but no joy.
Can anyone guide a non technical novice like me in the right direction?

cheers

David

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Hi David,

Firstly electrics is easy but you need to work logically.

Have you got a Volt meter, Digital or meter?.  Or you could use a light bulb on a fly lead.

Have you got a decent wiring diagram?   http://www.advanceautowire.com/tr24a.pdf

With the light switch turned ON there should be 12V at the dip switch  BLUE wire ( U )

If there is no 12V on the dip wire from the foot switch Blue/Red wire  (ur) then you need to go back towards the switch on the steering column.

Check EVERY Lucas connector.

If you do have 12V on the UR wire then go towards the lights - there shouldn't be too many connectors.  Check EVERY connector by taking it apart and cleaning.

Now check the BLACK wire from the  headlamps - these can also corrode.

 

Roger

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Supposing the bulbs themselves are OK , this is most likely a problem either in the dipswitch or in the bullet connectors to the lamps. Locate the connections on the switch and remove the blue and blue/red wires. Connect them together and try the lights. If you still have no dipped beam it isn't the switch at fault.  

I'm not sure where it is on a 4A but there is a bullet connector which splits the feed out to both lamps. ( On a 3A it is on the drivers side near the horns ).  If you can locate it  that is the next thing to check.  The fact that the main beam works means that for once this isn't an earth fault. 

The poor lighting on the dash is not related - it is just endemic. Many people convert to LED bulbs to improve it. 

Intermittent horns could just be a poorly-connected fuse. On the 4A it is a separate in-line holder in the wiring adjacent to the horn relay. If that is OK it may be a relay fault or the horn-push may not be getting a consistent earth connection.  Is the steering wheel and horn push still the original?

Edited by RobH
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David, several folks in the US, (including myself), on the Triumph Experience forum, found a discrepancy in the Advanced Autowire TR4A wiring diagram. It regards the wiring of the lighting switch, specifically the flash-to-pass feature. We’re not sure if this change was somehow for US market cars or some other factory change. At any rate. here is the wiring diagram I drew up to reflect what I found in my TR4A. Please excuse the scrawl (those letters are U not V) :unsure:

Jim

 

335F99A7-9355-4A02-A07F-F7C2FA1510C2.jpeg

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The split for the head lamps is at the front middle of the wiring loom which goes over the radiator duct with headlamps in the on position and using a volt meter or test lamp test on the blue/red wire here first its easiest then trace back dip switch to light switch as mentioned before undo every bullet connector and clean, you may even have both blown sealed beam units (or bulbs ).Your horn maybe the horn pencil or ring in the steering column, check the column has a good earth as for the dash lights change all to led don't forget to bypass the rheostat or change to one that works with led

Chris    

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Hi Roger, Jim, Chris and Rob, many thanks for your assistance and advice. As it happens the car has also now developed a fuel leak following a run out with the North Wales group on Sunday. As it’s still under a warranty from the dealer it’s gone back with a small list of ‘issues’ to be fixed. Hopefully all will be sorted. I must say I’m impressed with getting a 12 month warranty on a 55 year old car!!!

 

david

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Update on my opening post.

the car went back to the dealer with a fuel leak. Much to his credit, the electrical problems were also sorted. A new foot switch seems to have sorted the headlights out. The horn also now works better.

David

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