6500rpm said:
Common issue with the Daytime Brite Lites, I can't remember if I'm on my 3rd or 4th set but my last replacement is still in the box and I don't think it has anything to do with a bad batch, but the issue seems to be limited to the Taurus. Dan's always been good about sending replacements,but it's a pain in the a** to keep changing things out. My findings were the same as the OP, they only strobe with the engine running. I don't have anything handy, but the vehicle voltage was about 1.5-2v higher w/ engine running, amps were more or less the same . There are two B+ feeds to the module. At some point I was going to get a voltage reducer and try it out on each B+ feed and see if either makes a difference, if not, possibly use one on each line and see.
For now, I just clipped the ts trigger wires and killed the turn signal feature since it happened right at State Inspection time and I've switched gears to other winter projects for now.
The problem is that for my experiment, I need to install an actual voltage regulator (fairly cheap at Amazon), but I do a clean looking install. I don't think just putting a resistor on the B+ feed lines will drop the voltage to the 12v key off range (E=IxR). Dan did mention installing the new module and if it doesn't fix it, put the new LED's on so I'm not sure if they've changed something in the led board (added resistance?). I ran the trigger wire that determines if the DRL feature runs at full or reduced intensity through a hidden rocker switch so I can change between the two by flipping the switch and opening or closing the trigger circuit-hyper flash happens in both settings.
All my exterior lighting bulbs are factory with the exception of my back up lights that don't come into play with the issue. Post up anything you find, maybe I'll switch gears and play with the issue. I still have the last module with the fault installed so I just need to reconnect the turn signal trigger wires and mess with the supply voltage to see if it has any effect.
I came to a similar conclusion. Engine off, your voltage should be somewhere in the 12.5V-12.9V range. Engine running, it's going to be north of 14.0V. Mine runs pretty consistent at 14.4V. I figured that somewhere in between, a voltage threshold is reached wherein the controller begins to "freak out".
Your idea to run a voltage "reducer" on the B+ leads would be tricky. First of all, whatever you use would have to be able to withstand some pretty high current. I don't think the starter runs through there but things like fan relays and things do. It would likely be cost-prohibitive to do something like that. The problem with something like a resistor is that it may properly reduce the 14.4V down to 12.9V, but that would also mean when the engine is off, the 12.9V would be reduced down to 11.0V or less. This would be very bad. When my battery went tango-uniform last year, the car started doing all sorts of weird things. As soon as you shut the engine off, the radio would shut off (citing low battery voltage right there on the screen). My HVAC would randomly just shut itself off while driving.
Even if you were able to do so, you wouldn't want to. What you would effectively be doing is taking the increased voltage generated by the alternator away throughout the entire vehicle. This would have a multitude of negative effects, most prominent of which would be poor / non-existent battery charging. Increased voltage = good (within reason) so you wouldn't want to take that away. Not to mention, lower voltage = increased amperage, which compounds the problem above.
On the other hand, reducing voltage to that specific circuit that feeds the DRL's isn't a half bad idea. Rather than a resistor, what we really need is something of a voltage "stabilizer" or "regulator". I'll search for something a little more easy to integrate but it could be as simple as something like a cheap and readily-available L7812 chip. This shows an output voltage of 11.5V-12.5V with a target of 12V. Plus, it's a simple 3-pin connection (input, output, ground). I don't know what kind of current draw the DRL's have, but the 7812 is only rated for 1.5A.
I'll do some more digging on this. These problems can be fun but also maddening. If something like the L7812 fixes the issue, I would think that is something Dan could integrate WITHIN the controller. To be quite honest, I am surprised it doesn't already. Most sensitive electronics regulate input voltage as pretty much a first step to avoid unwanted or unpredictable behavior. This is a good case in point.
