This is my first posting on the forum. Looking for some help. I have seen a lot of talk on the blend door issue on 3 Gen Rams. IMO I don't think that is the issue here and I've tried a couple things in the hopes to single out/fix the issue.
2005 Ram 3500 4x4, 6 speed manual.
A few weeks back the fan would not start blowing at start up. It was intermittent for a week or so. Most of the time if I turned off the fan speed, and turned off the ac button before shutting off the ignition it seemed to have some affect on when I started to truck the next morning and the AC blower would function. This was only for a week or two and it was intermittent.
A few weeks back the fan stopped blowing all together. I can here it blowing at all as some have said they could what have experienced the blend door issue. I bought a new fan motor and unplugged the one in the vehicle. Started the truck but the fan never spun up. The fan was not installed, just plugged in the harness. Since the fan didn't spin up I figured it must be the control panel.
The control panel seems to work. When you push the AC button or the defrost button the lights turn on. The temperature control seems to work. When you have the selector set to Vents with the AC on, you can feel the cold air from the AC being drawn out of the vents. Especially if you have a window cracked to draw out the air when you are traveling down the road.
I just bought a used control panel off ebay, thinking that it must be the fan speed control portion of the controls that went bad. I plugged in the new/used on and still nothing.
I have checked fuse #36 and it seems fine. Even switched with another 10 AMP fuse in the fuse box.
I have not dropped the fan completely to see if the blend door is an issue but like I stated before it doesn't sound like a blend door issue here.
If I select recirculating AC, the cold air, the small bit that comes out with a rear window partly down from the vacuum of traveling down the road, the cold air stops and you can't feel it. Only on outside air can you get a small amount of cold air to flow out of the vents.
Sorry this is so wordy.
Anyone seen this and can steer me in the right direction?

 

Sounds like the ignition switch. Could be the resistor block, but usually when they fail you get high-speed fan only.

 

So....the blower motor is running but you feel NO air coming out vents? Recirc door broke and fell down. It's blocking it.

 

MIKE..no fan speed at all...none of the speeds selected get the fans spinning.

 

TNtech...no fan function on any speed. I purchased a new fan and unplugged the existing fan connection and plugged the new one in, holding it on the floor board to see if it wod spin up. It will not spin up on any of the speed settings. I did a voltage check and with the key in the on position with out the engine running, I am reading 12.5 volts at the connection. I don't know whythe fans arent spinning up.
This reminds me that a week or two before the blower fan stopped working I noticed on a couple occasions that I would shut the truck off. Have the key in the off position and suddenly the blower fan would start blowing right before I was gonna shut the door.
I can pull the existing fan out but I highly doubt I will find the recirculating door causing any problem.

 

MIKE...if there was an issue with the igniton switch would it make sense that I have 12.5V at the connection plug for the fan motor? What doesn't make sense to me is if I have electricity there why doesnt the existing fan or the new one spin up?

 

Lately, Chrysler has been switching grounds, not hots. My 300C does that. Had a devil of a time wiring the radar detector to the rear view mirror. I tried to find switched hots and couldn't. Then I tripped over a switched ground.

 

I agree with mike on the ground. Fab up a ground wire. Attach it to a good ground somewhere then to blower motor, see if it comes on.

 

I am assuming you're checking the voltage at the Blue wire? Check the blue w/ yellow from fan for ground. It splices into the high speed circuit from the HVAC head. This is why it defaults to high speed if the resistor goes open. If you have no speed at all, it's fan or control head switch.

 

Checked the fan plug. Key on position, ohms on the blue yellow (ground) I read 02.7 on high speed setting. 03.8 on all other slower speeds.
I plugged in a new fan out of the box again...with it sitting on the floor board. It still doesn't spin up.
Blue wire (hot) 12.4 volts. This is with the key out of ignition.