Alternator fried by LED headlights? (1 Viewer)

[scb71]

I installed LED bulbs in the low beams and running lights in my 2011 a couple of days ago. I did notice some quirks when I initially tried to turn the light switch to initiate them as I was installing. Lights on the dash went off and the push button start would not initiate. It’s as if the car froze up. I had to unplug the new bulbs to start and refresh the system but the car started right up and didn’t appear to have any issues. Therefore I next plugged them back in and started the car before turning the light switch on and they worked. After that point it was fine to turn them on with the car off so I thought perhaps it was just an initial acknowledgment or CAN communication of some sort but I didn’t think much about it actually.

Later that evening the dash ignited while driving with AHC errors, all sorts of error messages and yet the car was still running. The dash eventually turned off as I recall but kept running. A few minutes later though it just stopped in the middle of the road. It would not even attempt to restart. The side marker lights also remained on, which are not LED, with the car not running but the switch was still in auto. I think perhaps the truck didn’t recognize the turn off as it wasn’t turned off but rather just ran out of power and shut down.

I removed all the new LED headlights, reinstalled the old and attempted to restart the truck. The dash lit up as it thought about starting but no juice and it didn’t turn over or even attempt to. With jumper cables the truck did start but immediately died once the cables were removed.

Took the Lexus battery out and went to the dealer who tested the battery which had only 300 amps so they replaced for free. Obviously the battery was drained but was this just a coincidence with the LED headlights or could they possibly have fried the alternator and charging system with an electrical system issue?

With a new battery installed the car started immediately and ran fine but the battery light was on and the amps meter showed the alternator not charging as the amps were level at around 12 as opposed to higher. Drove the car immediately to the shop who is replacing the alternator as the car was not charging while running.

So back to my question- is it possible these headlights caused this issue or just a really strange coincidence? Low beams were Sealight H11, X1 model, and I know others have used Sealight with success. They look the same as the Hikari actually and fit in the housing with the original cover same as Hikari. They are the No fan design.

I look forward to the input and feedback.

 

[grinchy]

Led lights correctly installed would almost always have far less amp draw.
It might just be a coincidence.

 

[TeCKis300]

I second coincidence. And perhaps a bit causal, not so much with the LED lights themselves, but in another way.

During the install, you may have left the car on or the doors open for an extended period. Potentially aggravating a battery already on its death bed. Batteries at low states of charge or weakened can be dangerous to certain electronics. With voltage sag, some inductive components may demand significantly more amperage. The alternator is similarly effected as its voltage regulator attempts to bring the system up to operating voltage. Between a weak battery pulling down the system, inductive loads demanding power, the alternator has a tough job and will be pushing max current through its rotor, regulator, and rectifier. Conditions like this can significantly wear and kill things in the chain.

 

[scb71]

I second coincidence. And perhaps a bit causal, not so much with the LED lights themselves, but in another way.

During the install, you may have left the car on or the doors open for an extended period. Potentially aggravating a battery already on its death bed. Batteries at low states of charge or weakened can be dangerous to certain electronics. With voltage sag, some inductive components may demand significantly more amperage. The alternator is similarly effected as its voltage regulator attempts to bring the system up to operating voltage. Between a weak battery pulling down the system, inductive loads demanding power, the alternator has a tough job and will be pushing max current through its rotor, regulator, and rectifier. Conditions like this can significantly wear and kill things in the chain.

Thanks to both of you.
Additional color I left out. I did notice when I was doing the install that the battery had an odd amount of corrosion for a 23 month old Lexus branded battery. I have not had any issues with it starting but when I saw the corrosion I did unhook it and clean the connections, etc. So I put on my smart charger just for good measure. That was a few days before I did the install as I did that in prep to do this.

So I suppose this could all be related after all. Bad or getting bad battery, alternator at 10 years old getting aged and not working properly causing more strain, put int he LEDs at exactly the wrong time and poof my issue.

Is that what you all are suggesting? I know there could always be more to the story but my fear was that I stupidly put the LEDs back in and I blow up the whole system again after a $700 new alternator install.

 

[Sandroad]

I don’t think it’s coincidence. I suspect some aspect of the installation either fried an electronic component, blew a fuse, damaged a relay, or some combination of those. I don’t know enough about it to offer specifics, but I bet it’s not coincidence.

 

[scb71]

I don’t think it’s coincidence. I suspect some aspect of the installation either fried an electronic component, blew a fuse, damaged a relay, or some combination of those. I don’t know enough about it to offer specifics, but I bet it’s not coincidence.

Understood but what could possibly go wrong with an LED install when you are just plugging the lights into the harness? I suppose they could have been plugged in backwards at the worst but how would I confirm that? Anyone know what color on the Lexus harness side is positive vs negative. As I recall one was blue and one white

 

[grinchy]

Corrosion can be due to a loose or bad connection at the terminal, so the battery/charging side might have been in a compromized state for some time.
It's very possible that the light install created an issue, but almost certainly that would lead to a blown fuse, which doesn't seem to be involved here.
@scb71 did you change to LED high beams too? Mess around with the DRL resistor at all?

 

[TimCFJ40]

I don’t think it’s coincidence. I suspect some aspect of the installation either fried an electronic component, blew a fuse, damaged a relay, or some combination of those. I don’t know enough about it to offer specifics, but I bet it’s not coincidence.

Normally I would agree that a very recent modification should be prime suspect #1 when an issue arises right after that modification. That said, I'll agree with the other posters that there's really no way this is anything other than a coincidence. Even running the battery way down to dead and killing it wouldn't cause the alternator to be fried.

As to the bulbs themselves, there's really nothing they can feed back to the alternator through the vehicle harness. The worst possible case that is reasonable would be causing a short, but this would blow the headlight fuse and nothing more on the vehicle end.

 

[scb71]

Corrosion can be due to a loose or bad connection at the terminal, so the battery/charging side might have been in a compromized state for some time.
It's very possible that the light install created an issue, but almost certainly that would lead to a blown fuse, which doesn't seem to be involved here.
@scb71 did you change to LED high beams too? Mess around with the DRL resistor at all?

I changed the high beams a few days ago and did not mess with the DRL resistor. As soon as I installed them and saw that the DRL was on at full blast I simply removed them and then ordered a new set of just the low beams. Originally I bought a pack which had highs and lows and since us didn’t want the DRL issue I’ll return those.

Several days pass and then I installed the low beams and also the little t10 bulbs too. Didn’t mess with the highs at all.

Then the conversation picks up at the first post. Worked and then mid drive the car went haywire.

I just picked up the car with a new alternator installed and it’s working fine so far. Wondering if I should try the low beam led again or stick with my old, yellow halogen and move on.

 

[doru]

LED could not have damaged the alternator.
The circuit is designed for halogen at much higher current than what you use. Even if that is not the case the bulb circuit is on a fused relay controlled circuit.
What can damage the alternator is a damaged battery.

 

[doru]

Christmas lights phenomenon is known to occur in modern cars and trucks when there are problems with the battery. It is usually the first thing to check when it happens.

 

[TeCKis300]

LED could not have damaged the alternator.
The circuit is designed for halogen at much higher current than what you use. Even if that is not the case the bulb circuit is on a fused relay controlled circuit.
What can damage the alternator is a damaged battery.

Agreed. Nothing of the LED component could damage the alternator directly.

Thanks to both of you.
Additional color I left out. I did notice when I was doing the install that the battery had an odd amount of corrosion for a 23 month old Lexus branded battery. I have not had any issues with it starting but when I saw the corrosion I did unhook it and clean the connections, etc. So I put on my smart charger just for good measure. That was a few days before I did the install as I did that in prep to do this.

So I suppose this could all be related after all. Bad or getting bad battery, alternator at 10 years old getting aged and not working properly causing more strain, put int he LEDs at exactly the wrong time and poof my issue.

Is that what you all are suggesting? I know there could always be more to the story but my fear was that I stupidly put the LEDs back in and I blow up the whole system again after a $700 new alternator install.

The corrosion is telling. The battery was already on its way out. Though what's not clear is if an alternator issue caused the battery issue or the other way around. It's more rare that a battery takes out an alternator, but it's surely possible as a failing battery puts more load on the alternator.

 

[yOHda]

Understood but what could possibly go wrong with an LED install when you are just plugging the lights into the harness?

Literally anything can and does go wrong when we go monkeying about. But I wouldn't be concerned about trying lights again unless they are from an unknown manufacturer and have some internal issue. But I would think a fuse or relay would catch the problem before it moves further upstream.

 

[Sandroad]

I changed the high beams a few days ago and did not mess with the DRL resistor. As soon as I installed them and saw that the DRL was on at full blast I simply removed them and then ordered a new set of just the low beams. Originally I bought a pack which had highs and lows and since us didn’t want the DRL issue I’ll return those.

Several days pass and then I installed the low beams and also the little t10 bulbs too. Didn’t mess with the highs at all.

Then the conversation picks up at the first post. Worked and then mid drive the car went haywire.

I just picked up the car with a new alternator installed and it’s working fine so far. Wondering if I should try the low beam led again or stick with my old, yellow halogen and move on.

Well, since the new battery and alternator fixed the problems, it looks like it was just coincidence. The first paragraph in your first post threw me off in my guessing that some aspect of the light install caused the problem. That sequence of events, where everything died and "froze up" until you unplugged the lights and started over just didn't seem like coincidence, leading to the further issues. If you do reinstall, I suggest you use the sequence that did work.......have the LC running before you turn them on the first time.