And if the lights work when in the 4 way mode, then they must be wired correctly, no?

LED's are polarity sensitive and if hooked up wrong they will not function at all.

I stand by my statement that the LED lights are not drawing enough current to cycle the stock flasher when the turn signals on one side are activated.

When the 4 ways are activated, then the total current draw is apparently enough to cycle the flasher due to the fact that twice as many lights are activated.

We've had this happen in the shop at work just a few weeks ago.

 

Nope, not true. My 4-ways would work but no turn signals. Then I had it wired where everything worked until I turned on the head lights. Then I had it one way where my leds were not that bright. I went from a 3 wire light to a 4 wire. Come to find out, 2 of the wires were grounds.

It will be interesting to see what fixes the problem!!

 

Exactly.

Thats because:It sounds like you are referring to combination running lights and turn signals, therefore there would be a power wire and a ground for each function, for a total of 4 wires.

when you had them hooked up so they were dim, that would have been the running light wires , and when you hooked them up so they were bright, that would be the turn signal wires.

When you had it hooked up so it would work except when the headlights were on, you had the grounds inadvertently connected to the running light hot wire, and it was grounding back thru the headlight circuit, until the headlights were turned on, at which time the running light hot wire becomes energized also, therefore eliminating the path to ground.

BTW, I never said the flasher was bad, just incorrect for use with LED lights.

 

Yes, they are combination running and turn signal lights. At least I only had a few combinations to go through before I got it right.

 

So what was the outcome? Either your still running with broken lights or didn't post the fix? Just curious???

 

You should truck repairs Redbank Plains mechanic to help you with that repair on your truck.