Dodge Cummins Diesel Forum banner

21 - 30 of 30 Posts

·
Registered
Joined
·
42 Posts
Discussion Starter #21
I followed a great Youtube video that walked me through diagnostics in the fuse box as well as the FCM; as best one can. Looks like i most likely need the FCM. No surprise based on the research i have done.
I see i can get the FCM from Mopartpartsgiant for $272 with a $75 core charge; that keeps me from cutting this one open and investigating to see if i can fix it. Does this sound like a fair price for a reman part with a 1 yr warranty? Is there anything the Dodge dealer needs to do to program this to my truck? I try to stay away from them when possible. They will try to sell me a new truck.

Hope all are having a wonderful day.
David in SC
 

·
Registered
Joined
·
2,699 Posts
On another forum, there is an EXCELLENT, older write up by someone that details JUST how to inspect and rebuild the PDC/IPM/and FCM on these trucks.I have little doubt that with your pesevrverance and skills, you can prolly save your self some mooney and dod t yourself probably even do a better job. IIRC, internal corrosion was the only culprit.

I'll see if I can find you a link by this evening.
 

·
Registered
Joined
·
2,699 Posts
Found the link to Part1--

Read it through and see if it might help you do it yourself--

 

·
Registered
Joined
·
5,355 Posts
"She also saw both driver and pass read exactly the same in every aspect...with the exception of the passenger (bad) side being 0.1 volt higher than working driver side....11.6 versus 11.5 "

If no codes, ds low beam works, next would be proper resistance test of ps low beam wire circuits, different voltage reading could be showing issue.;)
 

·
Registered
Joined
·
42 Posts
Discussion Starter #25
Well shucks. I left a while ago to purchase oil to do my maintenance, and lights work fine. I don't understand it, but i will not argue with it, as i really don't want to buy an FCM right now. All prongs on all connections look shiny. If it goes out again, i might slightly distort the prongs on the IPM/FCM. Maybe there is a chance something is not making good contact, although wiggling and prying does not bring any flicker when not working. Furthermore, i would not suspect a defective FCM could "heal" itself, could it?
Baffling, but working for today.

Have a nice evening,
David in rainy SC
 

·
Registered
Joined
·
42 Posts
Discussion Starter #26
Good morning. I knew it was too good to be true; cranked truck this morning and low beam passenger light is out again. Back to the drawing board. I am finding it difficult to apply any logical troubleshooting to a phenomenon that can come and go.
I really have a hard time spending $272 on an FCM when my current one has the potential to work.

I will measure resistance on the wiring rghavana - thank you for the continued support.

This is a game, and i suppose i will keep playing until there is a clear winner or loser.

Enjoy the beautiful day.
David in SC
 

·
Registered
Joined
·
42 Posts
Discussion Starter #27
Good day. Still struggling with this querky phenomenon. I removed FCM last night and slightly bent the 3,4,6,and 7 prongs, as those are supposed to be the light input/outputs. No luck. I am now ruling out a bad connection.
Based on the Youtube video i used as a guideline, i would suspect my wiring is OK, or adequate to carry the load on the low beam side. I connected 12V directly to the fuse box and the bulb lit up. If this is still a possibility, i will measure the resistance. Any thoughts?

If there are no other suggestions, i might just swap the HB/LB wires in the bulb connection. I really hate to do this, but i do not ever use my HB, and i hate driving around with a bulb burnt out. I cannot really justify spending $300 on an FCM when mine has sporadically worked, unless someone feels strongly that the FCM has the potential to work/not work at different times. In my experience (which is very limted), when an electrical component fails, it fails until repaired or replaced. Any thoughts? It would be interesting if i had a known-good to swap in just for kicks.

I just want to get my silly headlights back working right. Soon enough i will be needing to go somewhere at night and may need them.. Hate to rely on fogs.

Thanks again for all the help. Sorry this has dragged on so long.
 

·
Registered
Joined
·
42 Posts
Discussion Starter #28
Well, i finally purchased a used FCM from MAKS. I put it in last night, and went from having passenger low beam out, to now having neither low beams and pass high beam is now out too. So, i got much worse, but most importantly i affected the issue. This leads me more to the FCM; does this sound reasonable? I have tested everything else i think i can test.
KUDOS to MAKS. I left a message and they returned my call within 15 minutes, and will have me a replacement FCM coming soon. Manuel also listened through my issue, and when i explained that all lights work when i apply 12V to the pins in the TIPM, he agreed the issue may be the FCM. Prior to that, he was leaning toward a TIPM problem.
We will see what the replacement rebuilt FCM does, and i will report back.
Good thing the days are long, as i do not really need headlights right now. Fog lights work for rainy weather!

Hope all are well in these crazy times,
David in SC
 

·
Registered
Joined
·
42 Posts
Discussion Starter #29
Shout out to MAK'S for the replacement used FCM; it solved my problem. It will be nice to drive to work tomorrow with headlights! I might turn them on needed, or not. Thank you kindly to all who helped me diagnose my issue. Hope i do not encounter this again.

David iN SC
 

·
Registered
Joined
·
1,726 Posts
Shout out to MAK'S for the replacement used FCM; it solved my problem. It will be nice to drive to work tomorrow with headlights! I might turn them on needed, or not. Thank you kindly to all who helped me diagnose my issue. Hope i do not encounter this again.

David iN SC
Thanks for updating your thread for the fix, this will greatly help people that need to troubleshoot in the future. Glad you got your issue sorted. Electronics are always a PITA!
 
21 - 30 of 30 Posts
Top