05 3500 5.9 electrical issues
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Joined: Sep 2009
Posts: 175
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My friend I feel your pain. I am in the middle of fixing my fuse box printed circuit board. It is known as the PDC, or power distribution center. There is also a FCM, the front control module. The FCM (A canbus enabled computer module) tells the PDC when and if to turn on some functions, including headlights, turn signals, brake lights etc. Together they form the IPM, or integrated power module. Sometimes my headlights will not work properly as well. These are all FCM controlled functions.
In particular, my left rear turn signal and brake signal will not work, and my front turn signals are both dead. These are functions controlled by the FCM.
Whoever made up this stupid complex system ought to be shot. This is all so that you get a light out indicator on your frigging gauge cluster when your bulb dies. Wow we really needed that eh?
To make it worse, the rocket scientist who made this system did not put it in a waterproof box. Instead they put conformal coating on the circuit board (Like a liquid plastic), and silver coated the contacts. Over time the conformal coating breaks and the traces corrode and fail. Yay. Also, there are little plastic "feet" which space out some inner plastic parts which they have located over circuit board tracers. A bit or grit and vibration and you have an issue. Fing brutal engineering.
Anyway, with the weird crap you have going on it's likely the FCM, PDC or both.
Heres place to get you started if you want to try to avoid the large $$$$ repairs.:
The power circuit for the trailer lights are controlled by relays on the circuit board of the PDC, as the video describes.
Chay
In particular, my left rear turn signal and brake signal will not work, and my front turn signals are both dead. These are functions controlled by the FCM.
Whoever made up this stupid complex system ought to be shot. This is all so that you get a light out indicator on your frigging gauge cluster when your bulb dies. Wow we really needed that eh?
To make it worse, the rocket scientist who made this system did not put it in a waterproof box. Instead they put conformal coating on the circuit board (Like a liquid plastic), and silver coated the contacts. Over time the conformal coating breaks and the traces corrode and fail. Yay. Also, there are little plastic "feet" which space out some inner plastic parts which they have located over circuit board tracers. A bit or grit and vibration and you have an issue. Fing brutal engineering.
Anyway, with the weird crap you have going on it's likely the FCM, PDC or both.
Heres place to get you started if you want to try to avoid the large $$$$ repairs.:
The power circuit for the trailer lights are controlled by relays on the circuit board of the PDC, as the video describes.
Chay
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Registered User
Joined: Apr 2016
Posts: 9
Likes: 0
My friend I feel your pain. I am in the middle of fixing my fuse box printed circuit board. It is known as the PDC, or power distribution center. There is also a FCM, the front control module. The FCM (A canbus enabled computer module) tells the PDC when and if to turn on some functions, including headlights, turn signals, brake lights etc. Together they form the IPM, or integrated power module. Sometimes my headlights will not work properly as well. These are all FCM controlled functions.
In particular, my left rear turn signal and brake signal will not work, and my front turn signals are both dead. These are functions controlled by the FCM.
Whoever made up this stupid complex system ought to be shot. This is all so that you get a light out indicator on your frigging gauge cluster when your bulb dies. Wow we really needed that eh?
To make it worse, the rocket scientist who made this system did not put it in a waterproof box. Instead they put conformal coating on the circuit board (Like a liquid plastic), and silver coated the contacts. Over time the conformal coating breaks and the traces corrode and fail. Yay. Also, there are little plastic "feet" which space out some inner plastic parts which they have located over circuit board tracers. A bit or grit and vibration and you have an issue. Fing brutal engineering.
Anyway, with the weird crap you have going on it's likely the FCM, PDC or both.
Heres place to get you started if you want to try to avoid the large $$$$ repairs.:
2004 DODGE RAM FUSE BOX TRAILER LIGHT RELAY REPAIR - YouTube
The power circuit for the trailer lights are controlled by relays on the circuit board of the PDC, as the video describes.
Chay
In particular, my left rear turn signal and brake signal will not work, and my front turn signals are both dead. These are functions controlled by the FCM.
Whoever made up this stupid complex system ought to be shot. This is all so that you get a light out indicator on your frigging gauge cluster when your bulb dies. Wow we really needed that eh?
To make it worse, the rocket scientist who made this system did not put it in a waterproof box. Instead they put conformal coating on the circuit board (Like a liquid plastic), and silver coated the contacts. Over time the conformal coating breaks and the traces corrode and fail. Yay. Also, there are little plastic "feet" which space out some inner plastic parts which they have located over circuit board tracers. A bit or grit and vibration and you have an issue. Fing brutal engineering.
Anyway, with the weird crap you have going on it's likely the FCM, PDC or both.
Heres place to get you started if you want to try to avoid the large $$$$ repairs.:
2004 DODGE RAM FUSE BOX TRAILER LIGHT RELAY REPAIR - YouTube
The power circuit for the trailer lights are controlled by relays on the circuit board of the PDC, as the video describes.
Chay
Thank you for all the info
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