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I NEED HELP! Old Electrical Problem Just Got a LOT Worse(02 WRX Dim lights/CEL's)

4K views 21 replies 6 participants last post by  nsibanez 
#1 ·
Hey everyone. So almost as soon as I brought my 2002 WRX home from buying it sometimes the headlights would dim and the dummy lights for the brake and battery would flicker on and off. Also any time I would hold the window buttons down after the windows were rolled up, the headlights would dim. I recently had the alternator and battery checked at two separate places. Once at Carquest and the other at a Toyota dealership where I got it inspected. Not sure if the stealership even checked it though cause a guy I know who just started workign there claims they dont have an "alternator dyno" to check it anyways. The Interstate Whatever-Tron II is only a year old and so is the generic alternator the PO had installed.

Fast forward to tonight. I let the car warm up with the remote start like I always do and drove off to the store. As I was driving right up the street I notied the battery and brake CEL's flickering. On the drive ghome from the store I noticed the headlights dimming a lot and the CEL's were staying on longer and longer. I pulled into my driveway and left the car running. I got some weird and counter-intuitive results as I was cranking the heater up and turning all the lights and radio on inside the car. The weird part is when I would crank the heater all the way up, the dummy lights cut right off, but everything still kept dimming on and off. I took several videos about 45 seconds long each and tried different things in each video to provoke the symptoms. These videos should help show you what I mean much better than I can explain it.

https://www.youtube.com/watch?v=BRioIPWsc2c&list=UU_kcHrCdodomaJGMHBvz2ug

https://www.youtube.com/watch?v=uw7_AISaAJc&list=UU_kcHrCdodomaJGMHBvz2ug

https://www.youtube.com/watch?v=XbFzv3qrrJA&list=UU_kcHrCdodomaJGMHBvz2ug

https://www.youtube.com/watch?v=wwu4ek6vgcQ&list=UU_kcHrCdodomaJGMHBvz2ug

https://www.youtube.com/watch?v=OkFXp33TpA8&list=UU_kcHrCdodomaJGMHBvz2ug

So what is it about the heater that makes the CEL's go away? Is it possible that the alternator pulley is bad or the belt is llose(even thought I checked it and its not) and when I blast the heater the A/C wheel kicks on and helps spin the belt? Could the alternator pulley have shot bearings and I'm helping force it to move by turning up the heater? Cause I didnt think the A/C compressor had anything to do with the heat. I thought thats what the electric blower motor was for. It seems so counter intuitive and I'm confused and pissed off about this. PLEASE someone tell me whats wrong with my charging system! Thank you for taking the time to read all this and watch the videos. I REALLY appreciate it.
 
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#2 ·
It's also worth mentioning that I installed a grounding kit a couple weeks ago. It seemed to keep the CEL's from coming on but I still had problems with the head and gauge lights dimming. I triple checked my work and know 100% that I installed it correctly per Paranoid Fabrications instructions(who I bought the kit from). Thnk you again for your help.
 
#4 · (Edited)
#5 ·
Well as I just said I had the alternator checked already Carquest and they supposedly did it at the Toyota dealership I got it inspected at as well. Kinda thought I already went over that too lol. Are you saying a multimeter can tell me something that the alternator diagnostic tool cannot? If so then I'll check it with my multimeter again.
 
#6 ·
OkI checked the alt and batt with my multimeter and they're both pushing 14v steady with no drops or spikes. Its the weirdest thing. I have to be driving the car for at least ten min. Before it starts acting up. I also checked all the fuses and they're all good. After a while it gets worse and worse until it starts making the engine rapidly drop RPMs. THATS what's worrying me about all of this. I wonder if it has to do with the aux. Electric fan??? Only reason I bring that up is because when the CELs flicker, as soon as I turn the heater up full blast the CELs go away. Also when I use my A/C or defrost I get a violent rumble and growling sound and my gas pedal starts shaking like crazy like an unbalanced garbage disposal is strapped to it. This is way out of my wheelhouse. Any theories guys?
 
#7 ·
I NEED HELP! Old Electrical Problem Just Got a LOT Worse(02 WRX Dim lights/CE...

A fan malfunction generates a specific CEL. Check the codes again just in case. I wonder if a marginal contact or component somewhere fails when heat, and thus resistance, builds up.
 
#10 ·
A fan malfunction generates a specific CEL. Check the codes again just in case. I wonder if a marginal contact or component somewhere fails when heat, and thus resistance, builds up.
Except heat drops resistance I thought
 
#8 ·
I haven't been able to check any codes. I haven't taken it to have a diagnostic run with the OBDII port. Would thes battery and brake CEL codes be stored in the ECU even if they only stay on for a maximum of a couple seconds? I was thinking that maybe a circuit like Tue fan or something was touching the battery or brake circuit and that's whats making the ECU throw CELs for the battery or brakes.

I see what you're saying. You think that as the engine gets hot, its making something like the brake or battery electrical circuit get hot and throw the CELs? And when I crank the heater the fans kick on and pull heat from the engine causing an whatever is going bad to cool down enough to make the CELs turn off? Man that's a heavy concept. Too far out of my league to diagnose. It makes sense though. It see!ms like the CELs never come on when I'm driving on the interstate or highway. Its only when I'm going 45 mph or slower and they also come on more frequently when I slow down and/or stop. This fully supports your theory.
 
#11 ·
Dobnkey, are you saying that there isn't a device at all that a dealership could you to try and diagnose why all this is happening? nsIbanez, I really don't know how that works. I took some more videos that you can see in my list on the right side of the screen on the YouTube page where the other videos are. When I get up to 50 mph or higher the battery and brake light never illuminate. Also I have a 300 watt power inverter and I noticed that at stops, the fan inside it does down and speeds back up as I accelerate. Also the headlights stop dimming once I reach highway speeds. Not sure if that helps narrow anything down but could an alternator test while the engines running show that the alternators fine but an alternator bench test could show problems that the other tester can't?

I know the alternator keeps passing all my tests but I just have this gut feeling that the alternator and possibly the battery is still the problem. Its an expensive hunch though.
 
#14 ·
Dobnkey, are you saying that there isn't a device at all that a dealership could you to try and diagnose why all this is happening?
I am saying the brake light and battery light have nothing to do with the OBDII system. So there is no device that can be plugged in to the OBDII port that can relay any information for those two systems other than battery voltage from the OBDII system. Could be the alternator is on the way out as it not supplying even nominal ampacity at idle. I would try cleaning the alternator stator and rotor assembly with electronics cleaner. If that doesn't work then I would try swapping out the alternator with either one from an STI(90a) or a 08+ WRX (110a).
 
#12 ·
Alright so I'm 90% sure its my alternator. Towline told me He found several threads from other forums about this same issue and 100% of the time it was either a matter of loosening ajdntightening all the bolts for the alternator and battery cables or the alternator was replaced and that fixed the issue. I'm gonna try the cheap way firs, tomorrow, by loosening and tightening all the bolts or nuts to the alternator and battery cables. If that doesn't fix it I'm gonna buy a new alternator.

I wanted to buy a higher output alternator from a newer WRX or Forester but Towline also told me He's read about people having problems when they do that. I haven't read anything about that, but is this true? I was thinking about getting a H.O. alternator that's been remained off of eBay. Are these alright or should I be looking for a lowish mileage untouched factory Subaru alternator? Thanks in advance everyone.
 
#13 ·
Those things I sent are a place to start looking for info about issue.
In some cases the alternator was replaced, other times the battery.
The things that kept coming up were about the ignition switch.
And the tensioner being bad. There were also suggestions about the wiring in transmition area.
I'm not an expert so I can't be sure if these suggestions will or won't work.

Before you start buying parts get it looked at at the Subaru dealer.
We're just speculating at this point. Has anyone else heard of the flashing idiot lights?
Electric systems can get complicated.
And I know just enough to get in trouble.
 
#15 ·
That's my next plan of action. Was thinking since the dealer is gonna cost at least $100 just to try and diagnose for one hour, that I may as well install genuine Subaru alternator since from what I read, 90% of the time that was the issue. So today I pulled all the fuses. They were all good. I checked belt tension and tightened the tensioner a hair. I also took off and tightened back down Tue nuts and bolts for the alternator and battery cables. Then I checked whatever plugs I could reach and lastly I topped off the brake fluid reservoir cause it was low. Same symptoms came right back as soon as I took it for a test drive.

Now on top of that for some strange reason whenever I press the brake pedal I get a loud click from the gear selesctor area. This happened right after I filled the brake fluid reservoir. Yes I used the recommended DOT 3 per the reservoir cap minstructions. This is making me think that maybe there is something going on with a plug around the transmission but who friggin' knows at this point? I've never owned such a complicated and finicky vehicle in all my life. Looks like since nothing decent is open today I'll have to wait till tomorrow to find an alternator without having to get it shipped, which sucks cause I need my car to drive for an hour each way to my prosthetic appointment. I'm worried my WRX will start acting up on the interstate now too, even though it hasn't yet. And I still don't understand why the hell the idiot lights disappear the very moment I turn my heater on full blast.
 
#16 ·
Donkey, of it is in fact the alternator should I even bother trying to clean it? Its only a year old and the copper coiling looks brand new. What year STI alternators? Any of them? Would any 2.5 l alternator be at least 90 amps? The ones from the 04 and newer I mean. I wanna wait till tomorrow so I can call the dealerships to see if I can GE one the same day since the soonest I could get one off eBay is Jan. 7th, but I'd much rather pay $60 for an low mileage used alternator. Just dunno if my car will last till the 7th before dying on me and leaving me stranded. Maybe I should order off eBay and buy a jumpbox for the meantime just in case. That way I'll still save a lot of money and have a backup plan if my alternator dies before Tue new one arrives. Can anyone suggest a good brand battery jimpbox I could buy locally? Thanks in advance.
 
#18 ·
Never mind. I read up on it and others have used the exact same one on my same year and model so I went ahead and bought it. I hope it ngets here fast. My Brother has a jump box He's gonna let me keep in my wagon till the alt gets here. Man I really hope this fixes the problem. Otherwise it's off to the stealership. I will let y'all know what happens after I install it. Thank you all for your help. Please lpost up if you have any other theories are questions that could help remey these strange symptoms.
 
#20 ·
The seller told me this is a 90 amp alternator. I hope this is the ticket cause today for the first time the ABS light also flickered with the brake and battery lights. Its also happening more frequently which is telling me that whatever is bad is failing more and more.
 
#21 ·
Problem solved! I got my replacement alternator installed today and have had zero issues since. The bearings were bad in the old "new" one the previous owner installed. That's why the problem got worse afte r I tightened the belt. I let the car sit and it idles way better. Also the idiot lights never lit up once. Then I used the multimeter on the alternator and battery and got 14.60 and 14.45 volts respectively. Drove it around a couple times today and had no problems what so ever. Hopefully I adjusted everything correctly and I won't have any more issues until this alternator dies on me. The car is acting much helthier all around. Ive had problems with bad bearings on other engine parts before and it can really drag the performance down. I expect to get better gas mileage to go along with the increase in power. Thanks for the help everyone.
 
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