Ok, Here's the facts:

2004 Dodge Caravan
No automatic climate control
No front and rear separate systems

Symptoms:
No air blowing from the vents
Blower motor is not turning on
A/C cooling fan is not turning on
If I turn on AC to max cold and press the recirculate button I can feel cold air gently rolling out of the vents when at highway speeds. (Guess this means the compressor is still kicking on but it seems the button is backwards because it goes away when I turn off recirculate which seems backwards)

Story so far:
Volume of air over the past few months has seemed to get progressively lower. On longer car trips the ac air volume would seem to steadily decrease over a few hours and eventually not get any air at all. Seems to have an abnormal amount of condensation pooling up under the van to the point it would make someone think there's some kind of leak from something else. Recently, about 10K miles ago, the engine was replaced due to a cracked head gasket that eventually got to the point of just replace it and move on. So I was thinking that during the swap they may have left the freon level low which could in turn cause icing on the evaporator and eventually block the air entirely. This made sense to me until the other day when the system stopped turning on at all. Before it quit entirely I thought to change the blower motor resistor in case it was something simple like that but it did not change anything. I suppose my next steps would be to play relay swap in the fuse box and see if I can identify a bad relay. Then move on to checking the fan connection and the blower motor connection for power. I'd love to hear some of the professionals thoughts on the subject. I can't think of much other than fuses or relays that would keep both the ac fan and the blower motor both from turning on unless there's a sensor somewhere that's gone out and the computer is intentionally keeping the system off. All input would be appreciated. Thanks in advance!

 

A few more clues:

Relay swap didn't work and all the fuses are ok in the fusebox.
I did notice that by leaving the ac on (even though it's not working) that after a few minutes the line coming out of the compressor (hope that's right on the low side) gets completely iced over fairly quickly. Also, the passenger side radiator fan is turning but the driver side one is not. I'm guessing that's the one that should be turning for the ac.

Could I possibly have had both the blower motor and the cooling fan attached to the radiator go out at the exact same time? That would be creepy.

 

Easiest thing to do now is check for 12vdc at pin #1 (black wire) at the blower motor connector with ignition switch on. If it's there and you see varying reistance on the ground wire at Pin #2 as you cycle the fan speed switch then change the blower motor.

You are implying one of the two radiator cooling fans is not turning on. Is that correct? If so, either that fan motor is binding or there is an open in the fan assembly harness. Looking at a wiring diagram the cooling fan relay has a single output to the fan assembly to turn on both fans meaning you should never see just one fan spinning.

If you have a binding fan motor get it changed ASAP otherwise you stand a good chance of frying the $80 rad cooling fan relay.

 

You're saying to check it at the blower motor connector, so does that mean unplugging it from the resistor and checking what's coming out of the resistor or is there another connector on the blower motor itself?

On the radiator fans, if there's a single output, would that mean if I unplug one of them that the other should stop also? Kind of like christmas lights being in a series?

 

> There is a connector on the blower motor itself. Power comes out of the TIPM (fuse relay box) to the resistor block. It then loops through the resistor block then out to the blower motor. You could check for power at contact #4 of the resistor block connector if that's easier. This would eliminate the TIPM as the problem if you see power, however, that misses the loop through the resistor block and the main power wire from the resistor block to the blower motor.

> No. Power to the fans splits at a splice creating a parallel circuit. Each fan uses a separate ground wire to a common ground point. Disconnecting one fan won't effect the other. The WD doesn't show it and I don't recall for sure but I believe each fan has it's own connector to provide the option of changing a single fan - or at least make it easier.

 

Ok, so the cooling fan issue and the blower motor issue are definitely separate problems. Good to know. I'll get the power checked asap. Sounds like if the cooling fan isn't turning, and the relays and fuses are ok, then it's pretty much dead in the water and in need of replacing.

And if there is power and varying resistance at the blower motor then it's gone out also.

Looks like $150 bucks worth of parts and some elbow grease to get it right.

 

Yes. Looking at the WDs I don't see a connection. As far as the cooling fans try spinning them by hand. You should be able to see right away if one is binding.

 

Just to update, I bought a replacement radiator fan yesterday and last night tried to put it in. I found out pretty quick they had sold me the wrong fan so I just boxed it back up. This morning I had already made an appointment with the mechanic to troubleshoot the ac system so I went ahead and left it with them. I got a call later saying it was definitely the blower motor but they wanted $350 parts and labor so I had to pass on it and just picked it up and paid their standard shop fee of $50 for their troubleshooting time. I took the wrong radiator back to Autozone and got my money back then went to Oreilly's and bought both the radiator cooling fan and the blower motor. I'm a pretty handy guy and I think I can handle swapping the blower motor out on my own. So I went to the park to find some shade and dropped the new radiator cooling fan in there since it was the easiest of the two to start with. After dropping it in there and pushing the connector on I turned on the van to make sure the fan was coming on like it was supposed to. While I was turning it on I thought I might as well turn on the ac just on the off chance the two issues are related. Well, lo and behold the ac came on full force with plenty of cold air. At first I was thinking the mechanic had fixed it and either didn't realize it (maybe just a loose cable somewhere) or the radiator cooling fan actually did have something to do with the ac not turning on. But I went and checked the radiator cooling fan and it wasn't even turned on because the connector wasn't pushed all the way in. I even unplugged the connector while the van was running and the ac still ran on high with cold air.

So at this point I don't know what to think. I called the mechanic back and told him the story. He said that sometimes when they are checking ground and tracing wires they might get the blower motor 'excited' but that it might not last very long. I'm not sure if they were just erring on side of caution and wanted to replace the motor because they knew that's what's happening. Either way I told him I'd just keep driving it like it is until it quits again.

Any comments or advice one way or the other?

Right now the new radiator cooling fan isn't on because the connector isn't exactly the right one and it doesn't want to seat correctly. It's tough to get in there and work on that though when the engine keeps burning your forearm like I'm playing a game of Operation.

Thanks again for all the advice.