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1970 Sequential light problem


Active Member
Hi all,
First some background -
It is illegal to have any red flashing lights on a UK vehicle ( The same for Bruno as well I think?)

So a guy here in the UK makes boards where the centre orange LED's are so bright they shine orange through the red lens - result!
There are pushbuttons on each board so you can choose 4 different ways of flashing as well.

My problem is that having a '70 ('71 was also the same) I'm trying to deal with the "marker lights earthing through the indicator filaments.
I've run a mishmash of LED and filament bulbs with an LED relay for a couple of years and it's worked fine but I now have this problem -
With the LED rears on sequential the relay in the board "clicks in and out" and the flashing is erratic BUT when I turn the side lights on everything is fine ( the relay on the board clicks in and stays in) and they work perfectly ( not a stable supply without the side light power???)
I've spoken to the guy who makes the boards ( nice guy but I think the marker light bit which he didn't know about has thrown him) and he said that the "clicks in and out" on the board is due to not enough power keeping the relay in.
I have tried adjustable relays which make the sequential's work fine but then "lock" all the other bulbs, I've also tried various combinations of LED and filament bulbs, LED and non LED relays but when I got the indicators to work OK in one combination as soon as I turned the side lights on they all locked up :mad: I also tried wiring a normal 21w filament bulb in parallel but that made no difference.

So my question is if I cut the black earth wire on all 4 marker lights and earth then properly will that stop the "back feed" and give me a fighting chance of getting them to work properly?
I like the marker light flashing bit and I've seen the "cougar unlimited fix" but it's very expensive for me to import and I can't be sure it would work with my board.

Perhaps Midlife can suggest a miracle cure ;)

Any thoughts, ideas gratefully received

I'm sure you can imagine how difficult it is to try and read through that and fully understand how you have everything connected, etc. That said, ensuring each and every component in the system has a quality ground (earth to you) can only improve performance of an electrical circuit. Improving the marker grounds as you question can't hurt anything.
1970 side marker lamps are awful with no true ground. They compare running lights to turn signals. If you provide a true ground, you can either have turn signals or running lights, but not both.
Mid is correct, the 70 side marker light wiring is an abomination that they only did for one year and learned the error of their ways. Below is a schematic (not a WIRE DIAGRAM) for the 70 turn signals. The scribbling in red shows how to convert it to the 69 system so you can possibly use the boards you currently have. The only aftermarket manufacturer that I am aware of that can make the LED systems work on a 70 is Vintage LEDs, but I don't know if they have a fix for the color problem in the UK. Maybe others have copied him by now.
All of the wiring is factory, that's a great diagram and to show how "delicate the balance" is i changed a front filament indicator bulb for an LED one and both hood lights half glowed even though the indicators were not on.
In theory it's only the boards I need to sort, an often used trick seems to be putting a resister before the LED's so that might be worth a try.
In my quest to fix this I have acquired 3 adjustable flasher relays, an LED specific one and the two that were in the car when I bought it but when it comes to the hazard lights the only one that works ( but I still have to have the sidelights on to work properly) at all was originally in the car and it's an Autolite made in the USA job :)

If i can get confirmation from the board maker it wont fry it I'm thinking of trying a wire direct from the flasher unit to the trigger wire on the board so it gets a "clean signal".
Thanks for all the input guys and I may be forced in the future to separate the marker lights from the indicators but that seems a bit like "giving up" and isn't that half the fun of old cars :rolleyes: mind you I blew 4 hazard light fuses today before I found the passenger side hood repeater had developed a short, probably from all the bulb changing I've been doing!
Well I've finally fixed the sequential light problem, the only problem now is I need another sign to remind me to turn the side lights off!!IMG_20230515_104739.jpg
If you want a signal inside the passenger compartment for running lights (sidelights for your car), there's a 2 wire single female molex connector near where the normal turn flasher wiring breaks out of the harness near the glove box area. Tap into that female molex, and route it to your dash lamp for headlight on indicator lamp.
I like the thought of "blinky blinky" after all I've got loads of spare flasher units from trying to get these to work!! and can you tell me what colours are on that molex Midlife?
Thanks for that, I'll get my torch, very strong glasses and some back ache pills and try and find it :rolleyes: