DRL Failures, Locker Indicator Flashing, and Chasing Electrical Gremlins

I raised that issue today. Not necessarily needing more data points, but that what one truck does vs. another is not guaranteed to be a proper comparison for diagnosis.

This seems to be especially true with these 3rd gen Tacoma’s. One peek in the OVTune thread will show you how much variance these trucks can have from truck to truck.

The issue is no one lets you speak with the FTS. They are totally shielded from “end user” contact by the dealership and Toyota corporate.

 

Just out of curiosity have you had any other issues? Do your non LED lamps flicker or pulse at all?

 

Very good move. Glad to see someone still has some scruples around here.

 

As it happens the first time I ever saw any electrical related issues on this truck, other than the DRL failures, was with one of the raptor lights flickering in the bay at the dealership while diagnosing this issue. That being said I have never seen them flicker before and apparently it hasn’t happened since. I know they were messing around with the connections so my hunch is that the connection on that light wasn’t right after they messed with it. Definitely no flickering with the first two DRLs.

Whether the raptor lights are an issue or not, they seem like they could be more trouble than they are worth so they will be coming off as soon as I get the truck back regardless of the outcome.

 

I'm also an EE and agree the factory diagnosis may be correct. I scanned through the 4 pages of replies here but didn't see what I was looking for, hopefully I did not overlook this being posted already: did you try isolating the grounds? Not with diodes or any sort of high frequency filter, how about re-wiring your aftermarket light such that it is grounded to the battery in a way such that it doesn't pull up the DRL low side. The easiest way to do this would be to run a thick ground wire straight from your lights to the battery negative terminal. Then have them re-run the diagnosis. These minor voltage spikes will be sufficiently handled by the battery. Just don't have any resistance on the ground leg that gets pulled up from current from your lights that pulls up the ground on anything else.

I run a 2004 Tacoma with simple wiring and even with it, I have a separate fuse box with its own independent grounds and high sides which are fully disjoint from the remaining vehicle wiring. If you have a gen2-gen3 with more complicated wiring and are tying your lights into pre-existing circuits instead of just running your aftermarket stuff straight to the battery, that is probably the problem. The more current your aftermarket stuff draws, the more it will affect the stock voltages in your circuits. You are probably just pulling too much current for what you are hooking into.

 

Other than the raptor lights which are super low voltage/amperage everything is “plug and play” (as advertised) into the factory wiring. I would do the isolate ground thing on the raptor lights but after the replies here they are just coming off the truck!

I have been looking into a power tray and blue seas fuse box with grounding bus so it seems like pulling the trigger on that is the right idea. Especially before I install the ARB dual compressor sitting in the garage.

 

LED drivers are very noisy so their reply does make sense. LED's need constant current and that is often achieved by making resonator circuits that feed an inductor which varies voltage to whatever it needs to keep current constant. For the BD lights, this could be why they are noisy. For your other stuff (not sure if your DRLs are LED or not) they may also run on resonators that make large voltage spikes based on that noise. If anything failing /is/ LED, it may be very sensitive to spikes at some certain frequency which Toyota doesn't expect as they didn't design the BD drivers.

 

I’ve messed with a lot of LED drivers and LED chipsets over the years (mostly custom reef aquarium lighting) but your post is way over my head!

If I understand you correctly, the Toyota driver has an extremely tight tolerance to voltage spikes and the BD (or something) on my truck is causing the spikes outside that tolerance?

 

Have they looked at the alternator to make sure it doesn't have a diode failure or one that is weak. I have seen a single diode failure in an alternator do some really weird stuff to the rest of the electrical system. This will also cause noise in the electrical system.

 

I suppose the key thought is that although the voltage spike voltage may seem low and therefore might be expected to be inconsequential, resonator (and many other) circuits can be very sensitive to frequency which can then cause high frequency voltage spikes at the output which can be larger than the original noise amplitude. This could cause problems which seem out of proportion with the seemingly small perturbations on your ground circuit.

 

That makes perfect sense! It seems like the only way to “disprove” their theory that aftermarket parts are the cause of the failure is to scope the circuit without the aftermarket parts and see if the spikes are still present. If yes, aftermarket parts not at fault. If no, aftermarket parts at fault.

 

To my knowledge no testing has been performed on the alternator. I will definitely ask tomorrow though and if they refuse to diagnose further, I’ll add it to the list.

 

Yep. Even if it is ugly, you could wire directly and re-run the test. The analysis will move the ball forward regardless of the outcome.

 

I mean you did F with just about every wire in that area. I don’t blame them for calling that out.

 

In regards to the DRL LED's dimming, the control is done via circuitry inside the headlights.

- Constant +12V from the DRL Relay applied to pin 1 on the headlight connector results in full brightness
- Constant +12V from the TAIL Relay applied to pin 2 on the headlight connector results in dimmed lighting
- Pin 3 is ground (the L/R LED controllers do not share the same ground point)

Jeff

 

I agree with toyota.

 

Thank you Jeff. Any chance of you having a schematic of that circuit?

 

“Calling it out” is not a sufficient basis to deny a warranty claim. They have to prove it. If you read through the emails that has been my issue all along. They went from unable to diagnose, to diagnosing that it was body ECU and approving a repair, to denying the claim due to aftermarket parts, to saying again they don’t really know what’s wrong, to performing a diagnosis that shows there is a signal noise issue but not that the issue is necessarily caused by the parts.

We are at a point now where I believe the failure may be caused by aftermarket parts, but not that it is being caused by aftermarket parts. Toyota is so close to closing this one out but the fact that they are refusing (as of now) to allow the dealership to perform the additional testing with parts unplugged leads me to believe that they are in fact hiding something or are simply unsure of their diagnosis.

Again, I’m willing to pay to play, but just show me why I have to pay, especially after the background of the diagnosis issues.

Based on what? I’m trying to make an informed decision about my next move here.

 

You should go in there shouting about the MM Act, works everytime.