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Discussion Starter #1
Hi all,

I was hoping you could answer a question for me and give me your opinion.

My Lights in my cab and the Instrument Cluster lights are out. Fuse # 35 is blown and it is a 15 amp fuse that goes to the Instrument cluster via a red wire.

I installed a new radio and a Tekonsha trailer brake about a month ago and just noticed my cab lights out last Thursday. The Tekonsha plugs directly into the port for my electric brake that was wired up by Dodge (When manufactured). I removed the cables from the batteries before installing it. Since I didn't know if this was causing my problem I unplugged it. I also installed a Pioneer Nex 4400 radio double din that replaced the Manufacture radio that went bad. I had Crutchfield make up my harness's for me and the only thing I had to solder was the power lead to my reverse wire for the back up camera. I removed the Radio and all connections including solder lead.

After removing all the equipment that I installed I then checked fuse position # 35 for a short and still had a short on the fuse position. I then removed my Instrument cluster and pulled the 3 plugs on the back. C1 is a white connector and the other two are grey. After removing all three connectors the short went away. I then put C1 back onto the Instrument cluster and kept the 2 grey connectors off the board and the short came back. When I removed it the short went away. I then pulled the board out and looked at it but could not see any burnt connections or chips on the board. I do not have a drawing for the board so I am not sure how to trouble shoot it.

So my question is, would you say my instrument cluster is bad? I can't think of anything else it could be since the other plugs are disconnected so that should only leave the instrument panel on the circuit. Am I thinking about this correctly?

Thanks,
Andy
 

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Discussion Starter #2
Hey all,
Ok so I finally figured it out. On the 2008 3500 Laramie 4x4 fuse 35 goes to your instrument cluster. It is spliced and goes into the C1 connector which is white on pins 25 and 26. The problem I was having is that none of my interior lights and my instrument cluster lights would not work. So I pulled out my instrument cluster and everything looked good. I then took my ohm meter and went on pins 25 to grd on the C1 connector. (the ground is on pin 13 or 14 the black wire) When I did this the ckt should open proving the short was not in my instrument cluster.

I then had a 26 gauge wire which I sautered to the positive and negative poles on a 12 volt light. I then put one end of the wire on pin 25 which was the red wire coming from the fuse and took the other wire and went across each of the pins in the connector. (I had a wiring diagram so I knew what each pin was) I skipped pin 2 since it was going to a different fuse. What I was looking for was a pin that would light up the bulb really bright. (this would be the one with the ground on it). I found pin 15 to be the bad leg of the circuit.

After looking at the diagram I realized that pin 15 went to all the lights in the cab, so I went and unplugged the back cab light, and the overhead console. The short was still there. I then went and took out the driver side visor which had a light in it. When pulling the wire down I noticed that it was shorted together like it had been mashed. Well that was my problem. This looks like a very poor design that lets it easily get mashed and shorted.

Now that I know how the circuit runs, If you have problems with all your lights going out in your instrument cluster and all the lights in the cab I would go and unplug all the interior lights and check if it is still grounded. Each component in the cab that has a light on it has a plug on it. So you can unplug them all, after disconnecting your battery, and plug your ohm meter in at the fuse to check for your short and see when it goes away.

Hope this helps somebody.

Andy
 

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I've had the issue of no cab lights, cluster lights, climate control backlighting and cargo light for a few years now. When I hit the cargo light button, the light in the cluster lights up to tell me it's on but the light itself does not come on. I can't find a blown fuse in the fuse panel and for a little while my cluster would go haywire every so often. For these two reasons I figured my cluster was just bad. Did I read correctly that you have an inline fuse feeding the cluster somewhere? Where did you get your wiring diagram? I have an 08.

I'll see if I can find the video of my haywire cluster in my archives.
 

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Discussion Starter #4
Hi Filthy,
The fuse isn't inline it is in your Power Control Module (Fuse Box) on the Driver side of your truck. If you open up the fuse box all the fuse positions are on the cover. The fuse that powers your interior lights and Instrument cluster lights is fuse # 35 and is a 15 amp fuse. If you remove your batter cables, mine is a diesel 08 3500, so I had to remove them off both batteries, and set your volt meter to 200 k ohms, then pull fuse 35 you should be able to measure across the fuse and see a reading of 0 ohms, direct short. This means the fuse is good and is not blown. Then if you put your meter on fuse position 35, put your meter leads directly into the fuse position. One on the right side of the fuse the other on the left side of the fuse(make sure battery is disconnected) you should read about 9 ohms on the 200 k ohms reading. This means the circuit is good. If it is around 2 ohms or lower you have a short but it might not be directly shorted.

After looking at this and trouble shooting it I doubt your cluster is bad. I would look at wires being shorted. Do you have lights in your visor?

I don't have enough posts to be able to provide a link to the Service Manual and wiring diagrams but if you go to Ebay and do a search for the 2001 to 2008 service repair workshop by jocrother0 you should be able to find it yourself.
 

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RedRam,

I do have the lights in the visor. I’ve read it is a common problem for the wires to these lights to short out. I’m not too familiar with using meters other than to simply check voltage so I appreciate the numbers you gave me. I will have to check this out when I get back in town and report back.
 

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Discussion Starter #6
Filthy,
I think most of the problems with this fuse probably are in the Visor. It is a bad design. The way it works with the light in the visor is that the wires run from the visorlights up into the ceiling. The visor is a straight post that goes up into the ceiling. The 3 screws that hold the visor in place go into a a metal piece that is welded in the ceiling. On top of that welded piece sits a plastic piece. That plastic piece is what gave out on me and I think allowed the post to smash the wires against the ceiling shorting it out. If you remove those three screws you should be able to pull the wires down and maybe get to the connector that connects to the wires going into your driver side pillar. My problem was between the light on the visor and the connector. If you cant get the wires to come out through the hole in the ceiling liner you will need to remove the plastic pieces from the pillars on the driver side first and behind the driver side to allow you to pull down the ceiling liner to see if the problem is in that part of the wiring. If it isn't on the driver side look at the passenger side and do the same thing.

There is a connector on the pillar of the driver side that can be disconnected also behind the plastice piece, but I think most of the problems are in the wiring above the ceiling liner. Hope this helps.
 

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I know it's been awhile but I'm finally checking back in after doing some diagnosing.

1) I pulled the a-pillars off on both sides and disconnected both plugs to all the overhead wiring, put a new fuse in and POP! no luck on that.

2) I pulled the climate control panel off and disconnected all plugs, tried new fuse and it popped again.

3) I remove the headlight switch and unplugged, added a new fuse and pop!

4) I removed the cluster and unplugged everything from it and the new fuse still went pop.

It could still be a short somewhere but if it is... it's somewhere in the loom which is going to be a PITA to find. My other thought is a the TIPM. I've read that if there is a short too often, the TIPM will close that circuit and no longer allow power to that circuit. I am wondering if it does this by grounding the circuit and shorting the fuse out to stop the power supply. I am looking to see if somebody is willing to let me install their working TIPM or cluster to simply test if that would fix the problem.
 
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