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Old 02-11-2014, 10:19 AM   #1
mdmaiorano
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Join Date: Feb 2014
Location: Indianapolis
Posts: 8
My Ride: 2002 325CI
Question Headlights Flicker and Cold Engine

Hey all,

New member here! Just bought a 2002 325CI as my second drive and a bit of a project car/fixer-upper. I'm sure I'll be posting a lot of questions and problems about it here soon, but had two I wanted to run by the forum that have me stumped as I'm new to the E46:

#1: When I turn the lights on, the xenons flicker and take a few second (sometimes like 10) to actually fire up and turn on like normal. I've noticed that if I rev the engine a bit I can usually get them to fire up fine, and then they are ok for the entire drive. Makes me think it's a battery issue and that reving the engine kicks enough power from the alternator to fire up the lights fully. Am I on base with this, and if so is there any way to verify that I need a new battery?

#2: I've also noticed that my car runs very cold, and as such, I am not getting a lot of cabin heat. Granted it's been freezing here recently, but thew car is garaged and my temp gauge shows abnormally low temps. My morning commute is like 30-40 minutes, and the temp gauge may creep just above the blue zone by the time I get to work. My initial thought is it something with the coolant not circulating through the system correctly, but I'm not sure where exactly the temp gauge is taking the reading from, or what I should troubleshoot to make sure coolant is indeed circulating correctly. Any suggestions?

I don't have a lift, but am handy enough to do just about everything else myself. I looked over the radiator and expansion tank, and can't see any leaks. Coolant level is also normal.

Thanks for the help all! I'm excited to be part of the club and hope I can answer some other member questions as I work though the car more.

-Mike
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Old 02-11-2014, 12:39 PM   #2
RayPooley
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Join Date: Jul 2012
Location: Liverpool
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Xenon bulbs work through ionization of the gas inside the bulb. Its possible that the bulbs themselves are deteriorating. I mention that because you don't mention it as a possibility. I would rule this out before going nuts on alternators, batteries and stuff. As for heat, maybe thermostat is stuck open.
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Old 02-12-2014, 01:53 PM   #3
mdmaiorano
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Doubt it's the bulbs themselves because both sides do it at the same time. It seems unlikely they would both be going bad at exactly the same time. Also I think I noticed yesterday that when it does it, if I put the blinkers on, they will kick themselves on fully.

Also don't believe the heat is a thermostat problem, because I'm not worried about the cabin heat, I'm worried about the fact that my temp gauge only slightly moves from nothing to just up above the blue "cold" range. I'm wondering if I've got a coolant circulation problem or something. In my 2005 RR (BMW engine), the same temp gauge will heat up and stay right at "medium". I would have expected the smaller 325 engine to function relatively the same way.

Anyone have any other ideas?

Thanks.

-MM
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Old 02-12-2014, 01:57 PM   #4
RayPooley
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Quote:
Originally Posted by mdmaiorano View Post
Doubt it's the bulbs themselves because both sides do it at the same time. It seems unlikely they would both be going bad at exactly the same time. Also I think I noticed yesterday that when it does it, if I put the blinkers on, they will kick themselves on fully.

Also don't believe the heat is a thermostat problem, because I'm not worried about the cabin heat, I'm worried about the fact that my temp gauge only slightly moves from nothing to just up above the blue "cold" range. I'm wondering if I've got a coolant circulation problem or something. In my 2005 RR (BMW engine), the same temp gauge will heat up and stay right at "medium". I would have expected the smaller 325 engine to function relatively the same way.

Anyone have any other ideas?

Thanks.

-MM
Temperature sensor bottom hose? Maybe it just telling lies.
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Old 02-12-2014, 02:05 PM   #5
mdmaiorano
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Could be. I'll have to check it out. What drives the cycle of the coolant through the system? I'm wondering if a pump is stuck or something, coolant isn't circulating, and that's why I get those low temp readings because the cold coolant stays in the bottom hose by the sensor.
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Old 06-14-2014, 09:02 PM   #6
wrench1173
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Join Date: May 2014
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My Ride: 2001 330i
Easy to fix headlight flicker

I had the issue of the flickering headlights even at an idle in the parking lot so I took the advice of the fine gentlemen above and this is what I did, and what I used to fix the issue. The pic is the items I bought at the auto parts store cost about 15 bucks but i can always use the other connectors and wire for something else. So take your right rear tail light disconnect the harness to the light housing look at the brown wire ends (both in the harness and housing) if they look the least bit corroded then there is your fault. Take the nut holding the entire brake light housing off, take the wire about 8 to 10 inches will work cut and remove 1/8 in for the connector for the post and crimp wire and connector together put on post and tighten, take the other end and put the brown wire and new wire together in the other connector and crimp plug harness back and housing and that should be it. I have attached the components that I purchased.
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Old 01-28-2016, 02:05 PM   #7
NallieBoop
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So, Wrench --

Begging pardon, but I'm at a loss to track your suggestion(s) here:

1) what advice of what fine gentlemen?

2) by what logic did we get to brake light housing repair for headlight flicker symptoms?

3) just what, exactly, are you doing with this wire and crimp connector stuff?? (a pic of what you used without any of how you applied same leaves me guessing)

4) perhaps I should ask if the "flicker" that you fixed was the same sort of thing I'm experiencing w/ my 2000 323i - where I'm looking like a donkey's rump while driving at night because my headlights randomly flash the weird way they do when initially turning them on (the momentary lightning flash before settling down to the normal glow) which other drivers ASSUME that I'm flashing my hi-beams for some weird raisin. Fact is, highs on or not, same flashing occurs, but without any regularity or predictability.

Perhaps this IS a deteriorated connection SOMEWHERE, considering that we've gotten LOTS of rain lately so humidity is abnormally high....

Thanks

the unwitting flasher
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Old 01-28-2016, 07:30 PM   #8
lmr2wil
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What Wrench was likely talking about two years ago was the taillight fix - http://forum.e46fanatics.com/showthread.php?t=512469 - see post #90 for instance on why they may have suggested this.
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Old 01-28-2016, 10:52 PM   #9
PastureOfMuppets
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Quote:
Originally Posted by NallieBoop View Post

Perhaps this IS a deteriorated connection SOMEWHERE, considering that we've gotten LOTS of rain lately so humidity is abnormally high....

Thanks

the unwitting flasher

Maybe a loose ground connection somewhere.
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Old 01-29-2016, 08:49 AM   #10
markusmarkus
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Google "BMW E46 hidden obc functions." Test #7 will show you the coolant temperature as seen by the ECU. It needs to be between 95*C and 100*C after a few miles of driving. If it never gets to that range the thermostat is suspect. They fail in the open position.

Then move onto test #9. This will show you the voltage seen by the ECU. Check the voltage when the:
- ignition is in the "run" position but the engine is off
- engine idling (~750rpm)
- engine at 2000rom.

Report back your findings.
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Old 09-27-2016, 02:34 PM   #11
NallieBoop
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Quote:
Originally Posted by mdmaiorano View Post
...

Also don't believe the heat is a thermostat problem, because I'm not worried about the cabin heat, I'm worried about the fact that my temp gauge only slightly moves from nothing to just up above the blue "cold" range. I'm wondering if I've got a coolant circulation problem or something. ...

-MM
I'm revisiting here because, although with the end of the rainy season my flashing issues went away - until LATELY, when they've mysteriously returned (uninvited, I might add) - so since I found this virtually the only thread returned to my search of "randomly flashing headlights" this is deja vu all over again.

Anyway, this time as I read down through it I picked up something that, though it's surely too late for mdmaiorano at this time, it may merit reconsidering:

my guess from the above quoted comment would be that mdm... thinks of a thermostat as the variable heater control in the cabin, rather than what's actually meant: the temperature-actuated valve in the engine cooling circuit. Were that understood correctly one would likely, logically suspect that first (as many of us did) as the symptoms are quite correct for a failed (or missing altogether) thermostat.

Lotta good this will do now, but there's a miniscule possibility that SOMEONE else might have a similar misunderstanding and benefit hereby. Slim to none, I know. Oh well - nothing to do with MY puzzler, either.

Sometimes I just have this funny urge to talk to myself, or type....

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