[krashDH]

My buddy hit me up the other day with a question about his truck. We both have 04.5's with the NV5600. He told me he was having an issue where his blower motor was being inconsistent...Ie he would turn the truck and it would stay on, until he got real aggressive with jiggling the ignition. Then it would finally submit and turn off. He said it seemed to be getting worse too. So I hopped on the forum since I haven't personally experienced this in my truck, and wow...there are a LOT of threads on this issue. People replacing ignition switches all day with no fixes, etc. After fumbling through a lot of worthless dead end threads, I found this, which was perfect for fixing the issue:

DIY fix for intermittent or no blower fan control

If you are experiencing problems with your fan control as I did such as fan not working at all, intermittently, or fan stays on when you turn the truck off, here is a fix that will cure it. The factory ignition switch is the culprit and when I called the dealer I was informed there are close to...

www.cumminsforum.com

The thread above was a huge help in solving the problem and we performed the fix to my buddies truck. Now, I haven't had any symptoms or anything to tell me that this would be an issue, but with how many horror stories about this poor electrical design and the potential hazards it could cause, it's a no-brainer to catch this now and prevent something like an electrical fire.

So I wanted to do a complete write up, since the ones I found were either half done, died out, or had no images. I'm not reinventing the wheel here, just putting together a better package of instructions and a wiring diagram that I made that can help others.

The background, in a nutshell, is that Dodge sent the power for the blower motor through the ignition switch. There are a series of radial "relays" in this switch. The blower motor can draw a LOT of amps...especially if it's turned on while you start the truck. So it's always a good idea to keep it off when you start if you haven't done this mod. Anyway, this high current draw (Dodge sends 2x 10 ga. wires into 2 terminals of this switch, one fused power line, and the other out to the blower) combined with the poor connector design can cause high resistance at the connector. It melts the connector and even the wiring sheath! My buddies had melted back from the connector a good 2" or so.

This is his connector:

Ok, no more background info, here's what we want to do....

Remove the power wire and feed power to blower from the connector, and run it through our own relay capable of handling the amperage (tried and true relay design, not the shotty dial relays in that ignition switch) and tap one of the ignition wires to trigger the relay, depending on when you want the blower to run.

You don't need much for this fix.

• Relay rated to 40A, 4 pin (Jump to Post #3 to see my relay of choice, if you want to mount it in a convenient location)
• Length of 10 ga wire
• Length of 16ga wire
• Connectors, shrink tubing, solder, taps, however you want to make your connections.

First, disconnect both of the neg. terminals on your batteries. Once that's done, pull your lower kick panel off:

Remove the rubber handle from the tilt adjust by just pulling in the direction of the arrow:

There are 3 T-20 torx screws to release the 2 steering wheel cover halves, remove them:

The halves will now just separate, be careful with them, they're flimsy:

Remove the 2x clockspring plugs:

Remove the bundle plug from it's hole in the steering wheel tilt bracket:

You can now see your ignition switch and have access to the connector. On the lower side of the switch, you can see a red tab (look in photo above, you can see it to the left of my finger). Release that to the passenger side. The come on top and GENTLY pry up the white locking tab to get it started enough to get your finger in there. It's fragile so be careful:

While you continue to pull up on that tab, pull the connector towards the front of the truck to release it from the switch. You can see the blue face of the connector:

Continued next post...

 

[krashDH]

Now to give us more access for working with the wiring, we need to remove the steering wheel tilt lever bracket and the ignition switch. Remove the 2x T-25 torx that are holding the bracket to the steering column:

Just let it dangle out of the way for the time being. It will be in your way the entire time. Oh well:

Remove the 2x torx that are holding the ignition switch in place. It's kinda a PITA to wiggle out of it's location but it can be done without removing anything else:

These are the 2 of the 3 connections that we need to work with in this fix. These 2 are the culprit. They are the large 10 ga wires. Notice the brown on one of my connections. I have not had any issues with my blower YET...but this is a telltale sign that if I didn't fix this, problems were ahead:

Now lets take a step back and understand what we need to do with the wiring. This is where you will need to get YOUR year FSM out and look to see what wire colors go where, for what components. I cannot guarantee they are the same as mine, I can only walk you through the process. I'm going to skip ahead and post my wiring diagram I made to do this fix, and explain it:

First off, Pin 1 and Pin 8 on the connector are the main power to the battery (1) and the blower motor feed (8). We want to remove or cut these wires. In this case, the colors for me were Red (Pin 1) and Dark Blue (pin 8). Pin 1 will be connected to the power source for the relay, terminal 30, and Pin 8 will be the "load", which is the blower motor, connected to terminal 87 on the relay. Terminal 85 on the relay is self explanatory, this needs to go to ground so that when terminal 86 sees power, it energizes the coil and completes the connection and lets power flow from 30-->87 out to the blower motor. This is just basic relay operation, probably didn't need to explain that.

Now comes the final part. We need a "trigger" wire to run to terminal 86 to magnetize the coil so the circuit completes when we want it to. Now, there are a few options, and it's up to YOU when you want it to come on. I circled the options in the image above for all of the potential trigger wires.

1. CAV 3 in the connector--> Blower runs when the key is in the RUN or START position
2. CAV 9 in the connector--> Blower runs when the key is in the RUN or ACC position
3. CAV 10 in the connector--> Blower runs when the key is in the RUN or START position
4. CAV 14 in the connector--> Blower runs when the key is in the RUN position

I chose option 4. I don't really ever need my blower motor to be running unless the truck is running. Plus it makes a nice, convenient, 16 ga wire to splice into, down in CAV 14, which is in the bottom corner of the connector. For me, it was a PK/YL wire. Now, there are a couple of wires in my case that are the same color. So make sure you are choosing the right wire CAV in the connector per YOUR FSM.

Ok, back to business. Identify your power and feed wires. Cut them at a locations where you start to have good, clean wire if your insulation is melted. Or you can do like me. I actually de-pinned them from the terminal:

If you want to de pin, you need to remove the blue keeper by depressing the tabs circled in green (2 on each side) all at the same time, in towards the body of the connector, while you kind of push the tabs towards the front of the connector to release it:

Then gently pry the small black connector circled in green towards the center while you pull the wire out the back:

Your wires are released, and you can clip them where you want based on the wire condition:

Continued...

 

[krashDH]

Now is a good time to find a mounting spot for your relay. You can mount wherever is convenient for your truck, but I found a location I liked based on the relay I chose to purchase. Here's the relays I got:

4 Pin Relay, Amazon

While I was looking around for mounting, came across this random, already tapped hole in the cast aluminum steering column. I thought, "hey, this looks like a good spot". I went to my screw selection and tried a couple, and what do you know, an M5 screw threaded in perfectly. I used an M5 -8mm length with a 6mm washer under the head, and some blue loctite on the screw:

If you mount it at an angle like this, it clears the steering wheel trim no problem. There's alot of room under there:

Here's the CAV 14 wire for my setup since I only want the blower on when the truck is running. Pink with Yellow tracer. You need to splice into this wire by means of your choice. Notice I said splice, don't cut it and route it anywhere, we still need that connection going into the connector. We just need to run our own wire to terminal 86 on the relay. Note that if you choose one of the other options based on your preference that you want the blower to turn on, this might not be the wire you tap into. So consult your FSM:

There's a lot going on in this pic I know, but I wrapped my bundle from the relay to the connector with Tesa Tape since there are some potential contact points depending on how long you make your wires and how your wheel is tilted. I won't go over the wiring since everyone will make their connections different, but use the wiring diagram above as a reference. I didn't quite make my trigger wire as long as I wanted but it functions fine and doesn't hang up anywhere:

Ground location for the coil on the relay is also up to you, but looking under the dash I saw a bundle of already grounded wires, so I made a connection with a ground terminal ring and ran it over to that ground point:

Before you cover everything up, connect your batteries and test to make sure everything is working. Start putting all the plastic back together, and remember to put the rubber handle back on the tilt lever:

That's it! Your blower motor power is now triggered through a relay and not the terribly designed, unsafe ignition switch. You can rest easy knowing that you aren't going to set your truck on fire.

 

[krashDH]

Hopefully this can help anyone in the future, although even if you aren't having issues, it's worthwhile to knock this DIY out as a preventive maintenance task