Intermediate lights flickering - please help

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krupnation

krupnation

10 Year
Joined
Dec 11, 2012
Threads
2
Messages
74
Location
Bellingham WA
On Monday, I picked up my LC at the airport after traveling for work (parked there 5 days) and on my drive home I noticed that my headlights were very slightly flickering, not totally off, just for a half a second they would dim then go bright again. I thought I was seeing things at first, but then it got more noticeable as I got closer to home. I then noticed the center console lights doing the same thing, going dim for a half a second then bright again.

Today is Wednesday and it's doing it more frequently now. I talked to my dad (retired mechanic) and he said it sounds like either the alternator or the serpentine belt going. Serpentine looks fine that I could see. I took it to the local auto place and they tested the battery and alternator. Here's where it's weird, the first test came out at 37v. The guy said that seems low for a car this big but the machine said it checked out "good". I told him to run it again and showed him the lights flickering when the car is running. Second test came in at 51v. Third test came in 37v. Fourth test came in a 44v.

Is my alternator toast? I've never seen anything like this on any car I've owned. I may add, the headlights, dome lights, all lights work fine when the car is off, no flickering. Turn it on and it looks like a light show. Any insight is much appreciated. I might also add that she is idling a little weird, rpm's are dipping ever so slightly when the headlights flicker. The voltage gauge on the cluster is also dipping slightly every time the headlights flicker.
 
1407driver said:
Much more knowledgable folks should be along to help you shortly... Is it only doing it when at idle?
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Yes, doing it at idle as well. Really strange...
 
1407driver said:
I'm confused- you sure it was testing at 30+ VOLTS? (12 volt system)
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My apologies, I can turn a wrench with the best of them but I stay far away from electrical stuff. Amps maybe?
 
Even if it was a mistake, 51AMPS is a ungodly amount of power going into the bulbs. Not to confuse you even more, but could it of been Watts? The bulbs are 55W (IIRC). Have you cleaned the contacts on the relay? I would look for a loose connection, or chaffing on any of the wiring. Also, check your grounds, a bad ground can cause flickering/dimming.
 
2000UZJ said:
Even if it was a mistake, 51AMPS is a ungodly amount of power going into the bulbs. Not to confuse you even more, but could it of been Watts? The bulbs are 55W (IIRC). Have you cleaned the contacts on the relay? I would look for a loose connection, or chaffing on any of the wiring. Also, check your grounds, a bad ground can cause flickering/dimming.
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I honestly do not know what the little machine he hooks up reads, all I know is it wasn't consistent. It has nothing to do with the HID's I put in, all the lights work perfectly fine if the car is off. As soon as it's on, it intermediately flickers headlights, parking lights, and interior lights. I'm stumped. Will a dieing alternator cause that?

Everything was working great for almost 2 weeks, no issues, and then after I picked it up from sitting for 5 days it started.
 
i had the exact same problem on my 100 series last year.. i posted here on the forum and had good guidance from a few folks, most notably MobiArc.. they thought it was my voltage regulator on my alternator that was buggered; recommended having it rebuilt for a 100 bucks. i decided to just buy a 'new' remanufactured denso alternator off amazon for about 250. i installed it within an hour and issue was gone. i also have peace of mind there were no ancillary issues with a purchase of the whole unit. there is a ton of crud that gets sprayed on it.

while you're at it, check the serpentine belt for cracks, make sure simple things are done first; ie. clean your battery posts and make sure you have a good ground. then move to your alternator.. the numbers you gave were weird.. i'd recheck with a voltmeter off the better when not running, then on the battery when running.. you should see teh alternator charging the battery and resulting higher voltage rate than when not started. if the alternator (or voltage regular in the alternator) is screwed, it will show fluctuating readings on the voltmeter. have some one increase the revs up to about 1800 and you should see teh voltage balance out at a higher rate than idle.. again, if it fluctuates, its your alternator..

i'm likely not explaining it well enough, send a pm to mobiarc or do a search for my previous post on the topic and you'll see his recommendation.. good luck.
 
Hey Jordan 345,
Thanks for the insight. I actually read most of your thread before starting this one as I didn't see the same symptoms (or overlooked them). Tomorrow I will go through the entire engine bay and check all grounds, clean battery terminals (they look good though), and check serp belt. I think it's the alternator but wanted to ask Mud before I spent some more coin on my rig.

One last thing, after I bought the truck, I found a couple of things that I didn't know what they were. Underneath the steering wheel, right above the gas pedal are two aftermarket wired in controllers. One I think was for a bass booster or something, and the other I just found out is for an LED strip that is synced to my music (WHAT!!!!). I couldn't believe it when I hit the switch by accident and it lit up, hahahahahaha. The dude from O'reilly's (who checked the alternator) said that the alternator may have been over loaded with aftermarket sound system stuff, something I know nothing about.
 
the previous owner must have been pumping ghetto music with the flashing lights.. i remember having a roomate that wired our house stereo up to bass when we had parties.. it was a trashy :)..

i don't know if excess power could have caused the alternator to fail; not my expertise.. as a point of reference, i run two amps; one at 800 watt mono channel and a 4 channel 1000 w amp.. never had a problem although i'm running a dual battery setup with the amps powered off my auxillary battery..
 
Jordan345 said:
Here is some info on alternators - might help understand context of how it may or may not be contributing to this problem. interesting read and lots of tech info.

http://www.billavista.com/tech/Articles/Alternator_Bible/index.html
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WOW, awesome stuff in that link! I spent almost 45 minutes reading through it this morning. I understood the gist of what an alternator does but that goes indepth and explains it very well. And he has a troubleshooting section at the end which is helpful. I'm going out to the truck after work today to do a full run through.
 
let us know what you find out. glad it could help
 
Well, thoroughly looked over every ground I could find, battery terminals, S-belt wear and tension, and everything looks great. Started it up and listened after she warmed up and I don't hear anything out of the ordinary, aside from the idle dipping intermediately like the dimming lights. Used a volt meter to check the battery and it was dipping and then going back to normal, dipping then back to normal. I think the voltage regulator is toast. I also found this helpful site: http://auto.howstuffworks.com/under...anical/5-signs-alternator-problems.htm#page=0

After looking over that website and the symptoms, I'm 95% sure it's the alternator. Getting it fixed next Monday and will report back.
 
Great job being thorough trying to find it. I would simply replace alternator and be done with it. What's a couple hundred bucks for another 200k and refreshed power generation.
 
Picked up the LC from the stealership yesterday after the new alternator was installed and viola! Fixed! I'm almost certain it was the voltage regulator or possibly a diode gone bad in the alternator that caused these weird symptoms. I drove over to my brothers house for dinner and back and no headlight flickering and no idle dropping. We'll see how she holds up but looks like that was the culprit.
 
glad to hear you sorted it out.. how much was the part and labour at toyota?
 
Part was $424, labor $190. I could've done it myself but with all that's going on right now (2 year old, new born, and work) I just didn't have the time. I'm just glad it's fixed.
 
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