As this gets more complicated I'm starting to consider just replacing the failed aftermarket modules and hoping for the best.

It's very possible those modules can be repaired.
I would suspect those mosfets marked Q1, Q2 and Q3 are probably defective and can be replaced.
Those mosfets are rated 2.5 amps max.
So it depends on how much current those LEDs draw before deciding on a replacement.

 

2 LEDs can be driven by each mosfet.

maybe so, but the mosfets will get very hot.

 

Not really as the duty cycle is ON - OFF-OFF

 

There are SIX total leds that need to be driven.
If you replace the CD4025B with a CD40106B Hex inverter, you can drive mosfets for all six LEDs from the CD4017B.

Sounds like that might be simpler (i.e. fewer overall compnenents). One PCB is preferable to two. Is there a way to run the Lt turn and Rt turn signals through one circuit, sharing the priciple components, then spliting the 2 groups of three LED's.?
I've down laoded your diagram, and I'm reading up on mosfets.

Can I use a BC335 transistor in place of the relay? That would free up som board space.

 

It's very possible those modules can be repaired.
I would suspect those mosfets marked Q1, Q2 and Q3 are probably defective and can be replaced.
Those mosfets are rated 2.5 amps max.
So it depends on how much current those LEDs draw before deciding on a replacement.

Guess I need to amp the lights... But of course, that's the one gizmo I don't have. Sugestions on a reasonably priced meter for a rookie? I know how to use it I jus dont own one.

 

Guess I need to amp the lights... But of course, that's the one gizmo I don't have. Sugestions on a reasonably priced meter for a rookie? I know how to use it I jus dont own one.

Harbor Freight has a decent meter with a 5 amp setting.

 

Sounds like that might be simpler (i.e. fewer overall compnenents). One PCB is preferable to two. Is there a way to run the Lt turn and Rt turn signals through one circuit, sharing the priciple components, then spliting the 2 groups of three LED's.?
I've down laoded your diagram, and I'm reading up on mosfets.
Can I use a BC335 transistor in place of the relay? That would free up som board space.

The relay can be replaced with transistors or mosfets and one board is sufficient.
Complete circuit, IC4 replaces the relays.

 

The relay can be replaced with transistors or mosfets and one board is sufficient.
Complete circuit, IC4 replaces the relays.
View attachment 355380

THANKS!!! Now I can order parts with some degree of confidence.

I'm thinking it might be easier to use plain perforated board rather than the GP PCB's I've bee using

BTW - the LEDs draw 0.024A on Hi and & 0.006 on Lo. I have a perfectly usable meter. I just had a bit of brain flatulance.

The bad news - I'm pretty sure my Jeep batteries are shot. They are 4-yr old, high-end, deep-cycle, Intersatates and they've had a hard life. I'm re-recharging them for a second test. It's always something...

 

BTW - the LEDs draw 0.024A on Hi and & 0.006 on Lo

That appears too low.
How did you measure them exactly?
Don't order any parts just yet.

 

Complete circuit, IC4 replaces the relays.

Not sure you need IC4. It basically is an inverter, and you already show a protected and filtered input; a 2N7000 would do the same thing. You have IC4 configured for a threshold voltage of 6 V, while a 2N7000 would come on at around 3 V. Does that matter?

ak

 

Not sure you need IC4.
ak

To provide a definitive cutoff when the cap discharges below 6 volts

 

The relay can be replaced with transistors or mosfets and one board is sufficient.
Complete circuit, IC4 replaces the relays.
View attachment 355380

The circuit modification below uses two CD4093 quad Schmitt-Trigger NAND gate packages, to relace the CD4025 NOR gate package along with IC4, M7 and M8.

 

That appears too low.
How did you measure them exactly?
Don't order any parts just yet.

 

Plug the RED probe into the jack to the right of the Black probe.
Leave setting on ma/A and read again to verify please.
Is the white lead on the LED for dim?

 

Plug the RED probe into the jack to the right of the Black probe.
Leave setting on ma/A and read again to verify please.
Is the white lead on the LED for dim?

 

The circuit modification below uses two CD4093 quad Schmitt-Trigger NAND gate packages, to relace the CD4025 NOR gate package along with IC4, M7 and M8.
View attachment 355390

The sequence effect will look odd since the turn signal timing is not synchronized with the sequence timing.

 

BTW - the LEDs draw 0.024A on Hi

Small mosfets like the BS250 will suffice since the current draw is only 24ma.

 

The sequence effect will look odd since the turn signal timing is not synchronized with the sequence timing.

I don't see any of the proposed solutions doing that.
My mod doesn't change whether it does or not

 

I don't see any of the proposed solutions doing that.

I believe this mod will work using two of the unused gates.

 

why not keep NAND with Schmidt trigger and use remaining gates to replace 555?