LED replacements causing trouble with vehicle lights

Q&A

Question: I thought it would be a cool idea to upgrade my tail, stop and turn lights with LED replacements so they’d be brighter. The first set of LED bulbs I tried didn’t get bright enough when the brakes were pressed so I returned them. The second set is OK except the ones for my turn signals flash really fast. Is this normal or OK? I can try a third set, but’s a pain to remove my lenses to change the bulbs. Suggestions, please.

D.H. Answer: Some imported/aftermarket LED retrofit bulbs are poorly designed, causing problems with socket fit, excessive length (conflicts with lens), poor brightness separation, flickering and premature burn-out. Assuming one finds a workable pair of bulbs that differ noticeably in brightness between tail and stop, the next hurdle may be a situation with the turn signals called hyper-blinking. This isn’t a fault with the LED bulb other than it draws much less electrical current than the incandescent bulb it replaced, which confuses the lighting control system.

Older vehicles would flash turn signals slowly or not at all when a bulb burned out because of the primitive thermal flasher used (cousin of a circuit breaker). This annoying but useful characteristic alerted one pretty quickly that something was amiss. When electronic flashers were developed, this same characteristic was kept, likely for safety reasons, but the flash rate was increased in the event of a low-current/bulb out problem, instead of decreased.

Your LED lamps, even though they are quite bright, likely draw about the same current, or less, of the original bulbs, somewhat imitating a failed bulb. Many newer vehicles may also set trouble codes or illuminate a lamp-out warning indicator, as the mismatch of current flowing troubles the CAN (controller area network) managing system.

The solution for hyper flashing or CAN mischief is fairly easy and inexpensive — the addition of a 50W 6-ohm resistor near each LED bulb added, spliced into the wiring (the resistor’s two leads are quickspliced to lamp positive and ground — in parallel with the LED bulb). These are widely available online for roughly $10 per pair. This workaround wastes roughly the same energy as the original bulb, in the form of heat instead of light, negating any energy savings reaped from the LEDs, but it does fool the control system into thinking everything is original. It’s important to mount the resistors to a metal surface such as the inner fender to dissipate heat, as they get warm/hot and could cause damage or failure if allowed to dangle.

LED automotive lighting is a nice improvement over incandescent lighting if done well. A whiter/brighter light with improved reliability is a good thing if kept within somewhat nebulous legal parameters. The lower current consumption is a big plus on older vehicles and trailers that often have sketchy electrical connections and circuit lengths as voltage drops are reduced throughout the circuit when current is reduced. Here’s a nicely done video on installing the resistors: youtube.com/watch?v=WyUh1ztBH84.

Q: We own a 2013 MDX Acura with 74,000 kilometres on it. We recently received a letter from Acura stating that the engine oil consumption exceeds client expectations. The original coverage is six years/115,000 kilometres. They’ve just extended it to eight years/200,000 km, whichever comes first.

With our present rate of driving, we will not get to the original warranty, let alone the extended warranty. The vehicle is serviced at the recommenced intervals by the dealer. The dealer indicates at this time that the vehicle is not using excess oil. We plan on keeping the vehicle for several years.

Obviously, we’re concerned about the repair cost if it does burn excess oil after the warranties are up.

E.H. A: You are averaging roughly 16,000 km per year, and by 2021 the engine will have about 115,000 km. If your oil consumption has not significantly increased by then, your engine might not have a piston-rings problem that led to the extended warranty. The issue is that the oil control rings may become clogged with carbon deposits. When that happens, the rings’ ability to scrape and return oil from the cylinder wall to the crankcase results in excessive engine oil consumption.

Although your engine might dodge the bullet, I would still urge you to have a talk with the dealership principal, who might be able to go to bat for you should the problem arise beyond the new warranty. Carmakers such as Honda are known to provide goodwill repairs. Brad Bergholdt is an automotive technology instructor at Evergreen Valley College in San Jose, Calif. Readers can email him at bradbergholdt@gmail.com.