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Discussion Starter · #1 ·
First, a little history; bought my 06 SRT used in July with about 79k on it.
At night, the headlights will dim and then get brighter. Step on the brake, they dim a bit, then get brighter. Sitting at a stop light, with foot on brake, I can see them dim and brighten. I understand that this car has many computers and sensors all cycling in and out; plus with the battery in the trunk and the regulator up front, I can understand some lag there as well.
With that said, it brings me to my first question: Would running parallel power and grounding cables from the battery to the front PDC and alternator provide a better path of least resistance and/or allow the regulator/battery/charging circuits to better handle the distance?
Also, in the EVIC I have noticed the voltage swinging a bit from high 12v to the low 14s.
In addition to this, the RPMs seem a bit erratic as well. It's not noticable on the tach in the dash, but in the EVIC, they vary from high 500s to mid 700s at idle.
I've attached a spreadsheet of log data taken from the OBD port using Torque.
Please review the data and let me know if any of our Charger experts see anything out of sorts.
The log covers about 28 minutes from just after a cold start, with a round trip on side roads, to the interstate, back to some side roads and back to the interstate, then off the exit ramp, side roads, and back to my parking spot.
Temperature outside is mid 60s today, overcast, humidity is fairly high as stormy weather is approaching.
If you follow the log from top to bottom, you can see the overall RPMs drop as the engine warms, and you can follow the vehicle speed and see when I hit the highway, ramps and stop lights.
I didn't get a chance to open it up to WOT, as there was a good bit of traffic and plenty of LEOs cruising around.
Sorry for the long post, but the erratic RPM and voltage swings have me concerned. It may be normal for this car, but I'm hoping some of our Dodge and/or Charger experts here will chime in with some valuable insight.
I had to trim the logfile down and zip it up due to file size restrictions.

Thanks!
 

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First, a little history; bought my 06 SRT used in July with about 79k on it.
At night, the headlights will dim and then get brighter. Step on the brake, they dim a bit, then get brighter. Sitting at a stop light, with foot on brake, I can see them dim and brighten. I understand that this car has many computers and sensors all cycling in and out; plus with the battery in the trunk and the regulator up front, I can understand some lag there as well.
With that said, it brings me to my first question: Would running parallel power and grounding cables from the battery to the front PDC and alternator provide a better path of least resistance and/or allow the regulator/battery/charging circuits to better handle the distance?
Also, in the EVIC I have noticed the voltage swinging a bit from high 12v to the low 14s.
In addition to this, the RPMs seem a bit erratic as well. It's not noticable on the tach in the dash, but in the EVIC, they vary from high 500s to mid 700s at idle.
I've attached a spreadsheet of log data taken from the OBD port using Torque.
Please review the data and let me know if any of our Charger experts see anything out of sorts.
The log covers about 28 minutes from just after a cold start, with a round trip on side roads, to the interstate, back to some side roads and back to the interstate, then off the exit ramp, side roads, and back to my parking spot.
Temperature outside is mid 60s today, overcast, humidity is fairly high as stormy weather is approaching.
If you follow the log from top to bottom, you can see the overall RPMs drop as the engine warms, and you can follow the vehicle speed and see when I hit the highway, ramps and stop lights.
I didn't get a chance to open it up to WOT, as there was a good bit of traffic and plenty of LEOs cruising around.
Sorry for the long post, but the erratic RPM and voltage swings have me concerned. It may be normal for this car, but I'm hoping some of our Dodge and/or Charger experts here will chime in with some valuable insight.
I had to trim the logfile down and zip it up due to file size restrictions.

Thanks!
I reviewed your file and everything looks normal. The headlight dimming has been discussed on the Forums for years, it has to do with the battery being in the trunk and as far as I know, no one has ever been able to mitigate it.

The jumpy RPM is inherent to the design and is affected by things such as power draw and AC cycling. The range you see is consistent with mine. You can try cleaning the Throttle Body to see if it levels out a bit...but otherwise it seems normal.

If you are feeling a rough idle it's often referred to as the "Hemi shake". If it seems like it's really stumbling it may mean that the TB is dirty or that the camshaft or crankshaft position sensors need to be replaced. Those sensors usually throw codes somewhere along the way but not always.

I don't see anything in the data file that seems to be out of the ordinary.
 

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I've owned Dodge cars for the past 10+ years.

1995 Intrepid, 2000 Concorde, 2001 Dakota, 2008 Charger, 2010 Charger.

They all had the light dimming thing...
 

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Discussion Starter · #4 ·
I appreciate you all reviewing my data. I have an 03 durango R/T and the headlights on it are extremely stable.
If it's normal for these vehicles, then I'll just have to live with it.
Any thoughts on the secondary power and ground cable idea? Would it help with the voltage swings/dimming issue?
When weather permits, I plan on loosening and scraping/sanding the battery terminals, power and ground cables between the battery, PDCs and alternator.
BTW the battery is a new Mopar brand battery, about 30 days old.

Again, Thanks!
 

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...When weather permits, I plan on loosening and scraping/sanding the battery terminals, power and ground cables between the battery, PDCs and alternator.


Again, Thanks!
I did all of that and saw no change in anything. I went further and added dielectric grease...no change. After a new battery...no change. Tried larger cables...no change.

Unless you redesign the entire electrical system and rewire the car, there won't be any change. Secondary power and ground cables won't make a difference.
 

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Discussion Starter · #6 ·
I did all of that and saw no change in anything. I went further and added dielectric grease...no change. After a new battery...no change. Tried larger cables...no change.

Unless you redesign the entire electrical system and rewire the car, there won't be any change. Secondary power and ground cables won't make a difference.
wow! Kinda sounds like you been there, done that for sure!
Guess I'll save my time and money and not do that then....
Would upgrading to HID headlights with a ballast get rid of the dimming?
Or is there any type of aftermarket regulator I can add to the headlight circuits to reduce/eliminate the dimming?
It's more annoying than anything....here I have this great, good looking, powerful car, and the lights dim on it....
 

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I doubt it has to do with the location of the battery. I'm betting these cars have the alternators controlled by the PCM instead of the old style regulators, and this is why lights dim now and again at idle. The Mercury Marauders I had used front mounted batteries and they did this quite a bit, and it was due to the PCM being cheap on the charging to not load the engine down that much at idle.
 

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I doubt it has to do with the location of the battery. I'm betting these cars have the alternators controlled by the PCM instead of the old style regulators, and this is why lights dim now and again at idle. The Mercury Marauders I had used front mounted batteries and they did this quite a bit, and it was due to the PCM being cheap on the charging to not load the engine down that much at idle.
Read post #13 from the SRT engineers themselves...


http://www.chargerforums.com/forums/showthread.php?p=486502&highlight=headlights#post486502
 
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