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Hi, Welcome to Just Answer, I am Clayton. I can help you with this.
What are the last 6 of the Vin#. So you need the dash wiring? Anything else?
In the remote PDM behind the driver seat, Take out the OPT/DIAG breaker or fuse out see if it kills the power to those circuits. I want to try that first.
Since it is trailer marker related, I am also wondering if something in the trailer wiring is causing this. I will supply you with some wire drawings I have of a 2004 columbia. Also, a FUSE PANEL schematic so you can use it to figure out the wiring.
Freightliner drawings are somewhat hard to read. You have to look at the break down and the circuit descriptions, Look at the From and TO chart. That will tell you circuit numbers, and pin locations.
1st find your circuit, then go to the From and the To. It helps if you print these out and spread them on a table. Get you a pen and piece of paper and write down pin locations.
When you look at the PDM schematic. Pull the instrument fuse again, check power on one those legs, with the ignition off, if you are getting power on one side of the leg, then it is back feeding from somewhere. Click the blue links for the Dash wiring, and the PDM schematic. It will take you to MediaFire, then it will take you to the Download now button, and you will have pop ups. I had to upload it here because the dash wiring was to big to upload it to JustAnswer. I checked the links, and they do work.
Dash wiring and PDM wiring.
Ya. Freightliner M2's have BHM(bulkhead module) and smart switches.
Also, find the other PDM(fuse panel) behind the driver seat, pull all those fuses and see if it kills anything.
Did you get the wiring diagram and the PDM diagram?. They are in the links in the previous posts.
Unfortunatly, this is the way Freightliner does there diagrams. Very few items have actual schematics like what you are dealing with in the automobile side. I use harness drawings everyday, and I do agree with you, they are kind of tough to read if you do not understand how to use them.
Some of the older trucks had actual schematics that were lots easier to read.
I am very familiar with how to read harness drawings. I used to trouble shoot prototypes for a car company, and rough hand sketched harness drawings are all that was available pre-production. I just refuse to use harness drawings to trouble shoot a production vehicle, because I know the full electrical diagrams have exist as they are required for production releases.
I tried everything we talked about today (plus some), and then I swapped parts and compared PDB circuits with another identical truck. This thing has to go out on a run, so I pulled the cluster fuse, made a fused jumper, and repowered using an empty spot in the PDB that is hot only with the key. The dimmer does not work, but full bright is fine. I need a complete wiring diagram for the dash & switch back lighting. If you don't have, I can get one from Freightliner, but it will take a few weeks to register for a free account. Freightliner has the wiring diagrams because they faxed copies to us, but they are not readable. The detail is good enough to see that they are not harness drawings, but actual wiring diagrams. Let me know if you can get the requested wiring diagram for next week.
What other Freightliner trucks would have the same or similiar dash lighting wiring? I am able to get to the M2 Business on the web, but I think as you stated they have the Smart Switches and modules, which makes the wiring much different.
After some digging, I found a schematic, it is most likely the same schematic you got faxed over from Freightliner help desk. I googled a 2004 Columba, and got a VIN to pull this up. The Century Class and the Columbias use the same wiring. M2 is totally different because it is multi-plexed. This is kind of generic because I am going with a different VIN from your truck, but it should be the same, the optional items in the diagrams use dashes instead of solid lines. So this should get you somewhere.
Entire Schematic and Interior Lighting Schematic
Clayton, U Da Man! This is exactly what I need. Thanks a bunch. Wish I would have thought to get the VIN today, but forgot. I am going to study these prints and when the truck comes back (hopefully some time this week) we'll be ready to fix it right!
Sounds like a very good theory, and this would be the 1st time I have ever seen this on one of these truck. So to prove this, you would pull the clock out of the circuit and see if everything starts working correctly?
If I helped you out in anyway, please accept my answer so I get credit.
That's my plan as soon as the truck returns.
I am going to accept your answer because you helped me tremendously by supplying the wiring diagrams. I am just waiting to verify the issue, to be sure I don't need anything else from you.
Clayton, back to the drawing board. My clock theory is bad because the truck does not have a clock.
Your suggestion of dimmer switch losing ground. I have completely pulled the dimmer switch out of the circuit and all the dash/button back lighting remains on with the key off. I also installed the dimmer switch in another truck, and verified the switch functions properly. Again, the only fuse or relay anywhere on the truck that causes the back lighting to go out is the "Instrument Cluster" 10amp fuse. Until we can figure out what is going on, I pulled this fuse, ran fused jumper wire to a empty fuse spot in the PDB that is hot with the ignition. This works fine except the dimmer does not work, always full bright. I would like to figure this out, and will review the wiring diagram you supplied again.
Disconnect the bulkhead connector for all the chassis wiring on the firewall, I think it might be the middle one, you will see all the heavy 10-12 guage wires in it.. See if your instrument cluster back lighting goes out. This will eliminate the cab from the chassis.
I am wondering if you are getting backfeed through the trailor wiring, not the pigtail. I have seen this wiring get rubbed and corrode, then cause problems especially with road salt and stuff.
That was my first thought. We can pull the trailer lighting relay out and the trailer lights go out, but the dash/backlighting stays on. We disconnected the trailer pigtail, then we disconnected the truck pigtail down on frame before it comes into the truck. The back feed has to be inside the truck somewhere I think. I even went through the interior dome lights to see if someone put the wrong bulb in and maybe we had a circuit crossed up, nothing. The way I'm reading the wiring diagram, if you pull the dimmer switch out of the circuit, the dash lights/back lighting should go out because their power comes through the dimmer switch. Somehow the circuit is staying hot and bypassing the dimmer switch, that is also why the dimmer does not work.
I know you don't want to do this, but swap out the fuse panel(relay panel). I have seen them short out. The one on the passenger side is the one I am referring to.
Did you say you disconnected the fuse panel behind the driver seat?. Completely taken that out of the circuit by unplugging all of the connectors to it?
Looks like they are very similar. I will upload these that is directly from your VIN, and you can decide. This schematic also shows a clock in the overhead. Freightliner uses the same harness on basically all there trucks, so it is possible the connector might be in there. Maybe got some water intrusion or something and is corroding across the terminals. These should pull up what you need. If you need anything else, let me know while we have a VIN #
and CLICK HERE
I don't have any international ones in my collection, I have quite a few Freightliner ones, and a few peterbilt wiring diagrams.
I collected a few wiring diagrams when I worked on the trucks. Peterbilt would email me or fax me some wiring diagrams, I had connections there. Of course I have connections at Freightliner as well.
I would be interested in buying the wiring diagrams you have for 2003-2004 Freightliner Columbia that show the AC systems. I will be responsible for repairing the AC systems on these trucks this summer, and would like to have the wiring diagrams in hand.
Any idea where I can go for the International radio diagram, dealer?
You might try the dealer for the radio diagram for the international.
You can pay me through giving me a bonus if you want to do it that way.
HVAC Electrical problems on these trucks I know like the back of my hand.
Here is the Main and the Auxilliary HVAC wiring diagrams for the VIN you provided in this question earlier.
B-Pillar Fuse panel Schematic
Here is the sleeper wiring diagram
that should be all of what you need. If you have to replace the Cab Blend air harness, the one that goes to the actuators, and the controller, it comes as one unit. What I have seen is the blower motor connector corrodes and melts sometimes. You can't get the pigtail for the blower motor buy itself, the whole harness is less than 100 bucks, and it is not bad to change.
There should be a "Bonus" button on your question page. I read the help section and it said you can leave a bonus at a later date.
Here is the link to the help page.
I am not that familier with the international, however, does'nt international use a Red Dot A/C system?
Western Star trucks use Red Dot A/C systems, and I do have some Western Star Diagrams.
It might be the same schematic as a 2002 Western Star with Red Dot A/C.
Here is the daytime running light disable procedure.