Im at my witts end I have searched the web called the dealer and I am finding out two different stories. Can anyone tell me where to find the voltage regulator on my 08 2500 megacab 6.7 cummins. Please help thanks and godbless
Ok so which would cause my head lights and dash lights to flicker while driving would it be the pcm or the alternator. Im very confused at where I should start to fix my issue. Thanks so far for all the help though
How old are the batteries? You could have them load tested at a auto parts store. A bad battery could cause some screwy things to happen. Could also be a bad ground.
Ok well I had one had one battery gobad so I replaced it. I have 105000 mils on my pickup so I guess I will have to start looking at elec. But I wonder if I shouldnt replace the other battery to help. I will go off this for now and get back to you all when im done with that. Thank again for alk the help.
If you only replaced one battery its possible you still have a bad/weak battery. It's always best to replace both batteries at the same time. I would have them both load tested and check all connections.
If it is cool outside the grid heater will cause this you will also see a load on the alt change this is normal also check the batterys one at a time disconected from the truck
I know this is an old thread but I didnt want to start a new thread with a simaler question... So from from what I'm gathering from info I see here is that I don't need to be concerned that my headlights go from normal to dim every couple seconds on a colder morning start? I notice it most on high idle for the first couple minutes but then it seems to go away, my volt gauge moves everytime it dims and this is because the grid heater is cycling on and off? Am I correct? Will plugging in my truck eliminate this on a cold start up?
It is indeed your grid heater cycling. Totally normal. Plugging your truck in will not stop it. Again, it's normal. Nothing to worry about. Be worried if it stops doing it.
i have had the same issue with my truck and im completely lost...new batteries, alternator tests good, but after 10-15 minutes of driving it will start to surge, the voltage will jump between 13 and 15 volts, makes it look like im flashing my headlights everywhere i go, it does it consistently regardless of weather conditions, doesnt matter what position the throttle is in, could there be an issue with the grid heater trying to kick on and, for lack of a better term, it being confused...again im lost on this one, i appreciate an help i can get
It is unlikely that the grid heater is coming on after 10-15 min of driving. You could disconnect a wire from the grid heater relay to make sure.
More likely you have a bad/loose battery cable, ground, charging wire to alternator. Inspect/tighten/clean all.
Alternator may test good, but it is difficult to duplicate 10-15 minutes of driving on a battery tester in the store (heat/vibration,...) I wouldn't rule out the alternator yet.
I agree with 2000, your alternator might show up some good results but can't really test the actual driving condition, pretty sure a alternator test won't tell you if you have a bad VR
Especially on Dodge where there is no VR in the alternator. The PCM is doing the voltage regulation function by pulse width modifying the field voltage to the alternator and monitoring resulting system voltage.
Now my truck is doing the light flickering thing. It will start doing it while driving down the road but when you come to a stop it will stop flickering . Volt meter will change back and forth 13 14 13 14. I have check all grounds ,batterys,...?????
I'm also having this issue with lights flickering at random while warmed up going down the road. Sometimes seems to be triggered by hitting high beams on, turn signals, or some other form of electrical draw. I have yet to check batteries and connections real close but i will as soon as i can get my truck in a somewhat warm work space! I'll post back with what I find also, seems that it should be a bad connection or battery!
Old thread but I'm having this same exact issue going on a month and I can't find anything wrong. I've cleaned every connection. Tested batteries and alternator. Any ideas????
well it quit for 2 weeks and about 3000 miles but started again today on my way from il to mn and I'm stumped on this issue. I've talked to several mechanics and they are quick to blame the ecm for the volt reg but $1500 and not a for sure fix is not a road i wanna go down at this time. could it be the alternator going bad?
Not wanting to start another thread, I know this one is old but my 08 6.7l is doing the same thing with flickering electrical components while driving. I have replaced the alternator, cleaned all electrical connections on the batteries. Even on the grid heater solenoid.. batteries hold steady overnight. (Tested individually). Ideas to look at?
I've had this issue several times and every time it's been a poor connection. While cleaning the connections on the batteries is important, also check the ground connections. Finally, I had a corroded crossover cable which also caused issues.
Amen to that! pulsating headlights, dash, and overhead lights. truck even had a funny sound at idle. occasional buzzing sound when key turned over but would start. random as all get out.
checked with clamps on both batts. drivers side post to post, clamp to clamp, and clamp to post both ways 14.35V while running.
Passenger side not so good. clamp to clamp read 14.35, but post to post (with clamps attached) was 12.41V. Neg post to + clamp was 14.35, but + post to - clamp read 12.41V pulled ALL clamps, gave each a seriously clean so they shinned like a diamond, same for all post, no issues since.
clean and solid connections / grounds are mandatory
Please check all the ground wires itself, they tend to burn it self out after so many years. I did experience this same issue and had cleaned all possible culprit. Found out one of the cross over wire was burnt. Replaced it and all was back to normal. Good Luck.
For what it's worth, I had replaced both batteries with Caterpillar brand batteries couple years ago and my truck did exactly what everyone is describing immediately. My lights would flicker similar to an emergency vehicle, dash, etc. Noticeably more than a grid heater cycling.
I replaced both Cat batteries with NAPA Legend (regular CCA as the manual recommend) and it stopped. I don't know why so sensitive to the batteries but it did.
Also make sure your terminals are super tight.
I'll tear more into this week and see what happens. Are there any specific vehicle frame grounds to check?
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