Triumph Spitfire 1500 Rear Brake Light Wiring Problem

[Black Cat]

Hi,

Now coming to the closing stages of my re-build, currently trying to sort out a few electrical issues.

The one I'm having a problem with at the moment is the rear offside brake/stop light. I have replaced all my bulbs with LED’s and  have checked they are all working, I seem to be getting a good power supply to the rear light cluster but the offside stop/tail light don’t seem to want to work, nearside works fine. I think I have reconnected all the cables in the correct position but I would be grateful if someone could confirm from the attached picture if my wiring is correct.

There is one terminal on the right which I haven't used, I suspect there should be a cable connected to this terminal but which one I’m not sure, If anybody can shine some light or perhaps a photo I would be most grateful.

[Black Cat]

I was wondering if it could be the bulb holder, might try and swap them round and see if it will work.

 

[dougbgt6]

What's on the other brake light connector? They should be symmetrical. What does the spare connector connect to inside the body of the unit?

Doug

[Black Cat]

Just swapped the bulb holders round and it worked fine so looks like a new bulb holder is required.

[Black Cat]

The other bulb connector doesn’t have the additional connect on the side so not sure what it actually dose.

[Black Cat]

Thanks Mathew, not going to Duxford but have ordered a new one from Moss so should be with me in a day or two.

[NonMember]

You need to connect the earth! The holders with the third terminal are generally better but that third terminal is the earth connection. Connect it! They don't rely on the dodgy body clips for earth, they use that connection that you haven't connected.

[Black Cat]

The black cable with the blue connector is the earth which is on the side of the light housing, not the holder, are you saying that there should also be an earth going to the spare connector, if that is the case why did the other bulb holder work when I replaced it with the wiring just as it is?

I know the bulb holders are not great for earthing but these ones are quite tight and do get a good earth.

[Pete Lewis]

yes not all claw holders earth through the claw  like youres has a seperate  earth  these rear lamps can be a nightmare of mixed up fittings and then add the dual pole offset bayonet pins for the stop/tail getting intermixed with single pole flasher and reverse bulbs all getting mixed together 

can make a nice flashing christmas tree effect 

getting it all wrong is quite common 

Pete

[NonMember]

1 hour ago, Black Cat said:

why did the other bulb holder work when I replaced it with the wiring just as it is?

You said that you'd swapped the one from the other side, which didn't have the extra terminal, and that one worked. Of course, because the ones without the earth terminal all earth through the fixing claw. Many of the ones with an earth terminal are electrically isolated from that claw and need the explicit connection.

[Black Cat]

I'll add a second earth cable tomorrow and let you know how it goes.

[Peter Truman]

When I got my Dolly Sprint around 5 years ago it had rear lights earthing issues, the cars original bulb holders didn't have earth spade connectors, I started soldering on individual earth wires to each bulb holder, it was a PITA,  talking to a close friend and fellow club member here he gave me a set of 6 bulb  holders single bulb and twin bulbs which had earth spade connectors as original fitment. I made up a separate earth wiring loom for each set of lights earthed to the body and since then there's been  no problems.

Try and source the big saloon bulb holders (earlier models I think) which had the earth spade connections on the individual bulb holders, it makes life a breeze.

[PeteH]

Herald Front sidelight/indicator units too have no dedicated Earth, and rely on the fastener to the bodywork, and ultimately the route via the Hood mountings??. All a bit "sussy" to my way of thinking?.

Pete

[Black Cat]

Right, moved the earth cable to the spare spade connector on the side of the bulb holder and the rear light now works, the only issue is it is not quite as bright as the other rear light, did try switching the bulbs over but still not as bright. Also left the other earth cable in place but no better.

I have a very good earth on the body of the car so don't think that is the problem. Could it still be an issue with the bulb holder, I have one on order so will change it next week or could there be another problem?

PS. just had another look at my photo above, could be the terminal needs a good clean.

[Pete Lewis]

check you dont have double pole bulbs and  single pole  claw fittings mixed up 

must be double for stop tail and bulb must have offset bayonet pins 5/21 watt  bulb so it only fits  one way 

flasher and reverse must be single pole claw fitting and single pole bulbs 21 watt 

getting these all intermixed is very common and add to that the some are self  earthed and some  need a earth makes the tail lamps a good case of chaos 

Pete