Indicator/hazard light wiring

[Napoleon Boot]

Hi all,

Last job on the snagging list to do before MOT, and it's electrical. Hands up, it's not the original BMC style wiring but if anyone with general electrical experience can confirm or deny my suspicions, based on my basic GCSE Physics knowledge, I'd be very grateful!

A while back I fitted one of these Lucas style hazard switches, and very nice it is too:
https://www.autoelectricalspares.co.uk/ ... -913-p.asp
It's been working very well and it's wired in as per the instructions.

However the flasher relay that comes with the kit is not suitable for LED bulbs, and I've recently made the switch to them, not least because they're brighter and don't drain the battery so quickly!

I swapped both the indicator flasher relay and the hazard flasher relay for a couple of these relays from Classic Car LEDs, and again, very nice they are too, they flash brightly at a good speed with a good loud click: https://www.classiccarleds.co.uk/collec ... king-sound

However! Unlike the original three pin flasher relays which had a power in, load out and a feed out to the dashboard telltale light, these only have a power in, load out and an earth pin. So no tell tale light on the dashboard.

I scratched my head, and then thought that if I ran a wire from each indicator circuit to the dashboard tell tale, and then earthed it on the chassis, in theory it should flash when either circuit, or both circuits are live. Here's a sketch to hopefully illustrate what I mean:

IMG_8420.jpg (232.08 KiB) Viewed 3025 times

I wired it up and it works, however now all four indicators always flash together, whether I'm using the indicator switch or the hazard light switch! I can hear that the hazard light switch is operating the hazard light relay, and the indicator switch is operating the indicator relay, so that side of things is working as it should.

My hypothesis is that the connections I've made to the dashboard light are allowing current to feed back to both circuits whenever either is live, hence all the lights flashing together. To solve it, I would need to put a couple of diodes between the indicator circuits and the dashboard light (indicated in red on my diagram).

Does this sound plausible?

[Steve Phillips]

Yes you are joining both circuits through the tell-tale bulb, using a one way diode in each feed will stop your problem, just remember to get the diodes the right way round...

[Napoleon Boot]

Yes you are joining both circuits through the tell-tale bulb, using a one way diode in each feed will stop your problem, just remember to get the diodes the right way round...

Perfect, thanks Steve! I'm glad something stuck in my brain from school. Hope you're well!

Seb

[geoberni]

Does the Red light in the Hazard Switch still flash?

Without that, I believe your system will not be MOT compliant as you need to be able to tell the difference between Indicators and Hazards operating.

[Napoleon Boot]

Does the Red light in the Hazard Switch still flash?

Without that, I believe your system will not be MOT compliant as you need to be able to tell the difference between Indicators and Hazards operating.

Yep, the hazard switch flashes red when activated (and not when the indicator switch is used), so as soon as I get the indicator tell tale sorted everything should be ready for the MOT. I even replaced one of the numberplate light fittings which had disintegrated, a nice excuse for a bit more shiny chrome! All that's left is to top up the washer fluid.

IMG_8418.jpg (316.84 KiB) Viewed 2995 times

[pgp001]

Just looking at your circuit you have not only joined the left/right circuits at the dash warning lamp but also at the hazard relay output.
A quick google search will produce a few wiring diagrams, here is one as an example.

https://www.autoelectricsupplies.co.uk/ ... iagram.jpg

Phil

[Napoleon Boot]

Just looking at your circuit you have not only joined the left/right circuits at the dash warning lamp but also at the hazard relay output.
A quick google search will produce a few wiring diagrams, here is one as an example.

https://www.autoelectricsupplies.co.uk/ ... iagram.jpg

Phil

Thanks Phil,

Apologies, that's me oversimplifying that bit of the diagram and confusing matters. The switch/relay assembly is as in the diagram you link to, the DPDT switch has separate wires out to the left and right indicator circuits so all should be good. The only additional wires I've added since changing to LED flashers and bulbs are the two I've drawn diodes on.

Typically, I've now discovered that Classic Car LEDs sell a diode and harness for exactly this situation:
https://www.classiccarleds.co.uk/produc ... 7ac4&_ss=r

Fitting it would involve removing the steering wheel, dashboard trim and instrument panel again though - gah! Everything worked fine with incandescent bulbs, the current creep seems to be affecting the LED bulbs because they require much less current to operate. Maybe I'll just put the old bulbs back for the time being!

Seb

[Napoleon Boot]

Just looking at your circuit you have not only joined the left/right circuits at the dash warning lamp but also at the hazard relay output.
A quick google search will produce a few wiring diagrams, here is one as an example.

https://www.autoelectricsupplies.co.uk/ ... iagram.jpg

Phil

Thanks Phil,

Apologies, that's me oversimplifying that bit of the diagram and confusing matters. The switch/relay assembly is as illustrated in the diagram you link to, the DPDT switch has separate wires out to the left and right indicator circuits so all should be good. The only additional wires I've added since changing to LED flashers and bulbs are the two I've drawn diodes on.

Typically, I've now discovered that Classic Car LEDs sell a diode and harness for exactly this situation:
https://www.classiccarleds.co.uk/produc ... 7ac4&_ss=r

Fitting it would involve removing the steering wheel, dashboard trim and instrument panel again though - gah! Everything worked fine with incandescent bulbs, the current creep seems to be affecting the LED bulbs because they require much less current to operate. Maybe I'll just put the old bulbs back for the time being!

Seb

[pgp001]

Hi

I retained my standard bulbs for the indicators so as not worry about the problems you have had, I reasoned that the amount of current they will be using is going to minimal when the are not lit for more than a few seconds so LED seemed a bit OTT.

I have found some excellent side lamp bulbs that work very well however.

https://www.ebay.co.uk/itm/2X-1156-BA9S ... Sw905dU57c

Phil

[Napoleon Boot]

Hi

I retained my standard bulbs for the indicators so as not worry about the problems you have had, I reasoned that the amount of current they will be using is going to minimal when the are not lit for more than a few seconds so LED seemed a bit OTT.

I have found some excellent side lamp bulbs that work very well however.

https://www.ebay.co.uk/itm/2X-1156-BA9S ... Sw905dU57c

Phil

Thanks Phil,

I had planned to keep the indicators standard as I like the way the light gradually fades in and out with incandescents, but after breaking down and needing to keep my hazard lights flashing for a long time, I was a bit worried about draining the battery if it happened again and ending up in the dark with no lights! I've replaced all the bulbs except the headlights now and I'm very pleased with the improved performance. Compared to modern cars the lights on my Traveller are minimal, so the more visibility the better!

Seb

[geoberni]

Quite honestly, although I too have fitted a hazard Unit (one I had in the shed that had previously seen use back in the mid 70s), I don't think the Minor indicators are really useful as genuine hazard markers. I know some moderns, particularly VWs have really small indicators on the rear, I think they're rather useless too...

I brought a magnetic base LED Beacon to to use if I actually break down, having done so twice on the A1 shortly after getting the car....

[Napoleon Boot]

I brought a magnetic base LED Beacon to to use if I actually break down, having done so twice on the A1 shortly after getting the car....

That would have been my preference - much easier than wiring a switch in - except the roof and rear panels of the Traveller are aluminium so it wouldn't stick! Mind you, even in broad daylight the LED indicator bulbs I got are dazzlingly bright - brighter than a modern van parked alongside with its hazards on. I'm well pleased with them.

The only lights which I'm not too happy with are the brake lights, which currently have nasty pattern lenses which are made with darker, less translucent glass than the original Lucas beehive lenses. For some reason they're all you can get from the main suppliers at the moment, and they're rubbish. I have a couple of second hand originals on the way though.

Just as an aside, these lenses are one of my earliest memories of cars - I used to love seeing them as they reminded me of Jelly Tots...

Seb

[Napoleon Boot]

Well, I disconnected the dashboard tell tale lamp and the wires I'd added to it, and everything is working as it should. Once the diode and harness from Classic Car LEDs arrives, I'll see how they recommend fitting it.

I went for a quick test drive after doing a few other little jobs, and took this photo which shows how bright the new indicator bulbs are!

Peggy in Highgate Village.jpg (2.93 MiB) Viewed 2905 times

[geoberni]

I love the fact that you found an old B&W road sign to pose by.....

[Napoleon Boot]

I love the fact that you found an old B&W road sign to pose by.....

Well spotted!

[pgp001]

That is what you would call a "Timeless" Photograph.

Unless I have missed something it all looks period, even down to the tax disc ?.

Phil

[Napoleon Boot]

That is what you would call a "Timeless" Photograph.

Unless I have missed something it all looks period, even down to the tax disc ?.

Phil

It's an original 1971 tax disc, but if you look very closely, it has the wrong reg number and it's not for a Morris unfortunately! It was a present from a friend who found it on eBay. The Zoom ice lolly air freshener isn't strictly period, but it has the right sort of vibe and smells nice!

Seb

[Napoleon Boot]

Just a final post to say that I fitted the diode harness from Classic Car LEDs this afternoon, it was a piece of cake and everything is now working perfectly. My new, old stop light lens arrived today as well, so now all my rear lights are bright and visible. Here's a snap of the the original Lucas and new unbranded pattern lenses - you can see how much more opaque the modern one is and it makes a big difference to how much light gets through, even with brighter LED bulbs.

Seb

IMG_8443.jpg (554.11 KiB) Viewed 2801 times