[Leo Monahan]

Several weeks ago the A/C blower began operating intermittently. First symptom was occasionally it would not run. Next was when running, the speed control was unstable. Finally it failed totally. The fan relay and all other controls were operating normally. The Variable Blower Control (VBC) was not heating. I replaced the VBC and the blower began working normally. 2 days later it reverted back to the same symptoms. Another new VBC and it was working again. 2 days later the same thing. No heat from the VBC. I replaced the in-dash controller twice and the same thing, works for a short time and then stops. I removed the Glove Box, VBC and Blower motor from the dash and ducting. I tied the blower to the lower Glove Box brace and started trouble shooting in earnest. The blower motor was the issue. I replaced it and all is fine now. I pulled the motor from the plastic housing and found the motor had a significant amount of rust on the outside casing. When I removed the blower motor initially I found a handful of leaves in the squirrel cage. My best guess is that at some point of time leaves had clogged the condensate drain backing water up into the motor. I have had this truck since new and have never replaced the in cabin micro filter nor cleaned the condensate drain tube. Today I will rectify that. I will post any further findings as I progress.

 

[Ducks_and_dogs1984]

Condensate drain tube? Newbie when it comes to ac stuff. Where is this located and how hard is it to get to.

 

[Leo Monahan]

The root problem appears to be that the micro fiber filters were never installed. I have owned this truck since new and never knew that the replaceable filters even existed. In my case they didn't. The access panel has never been removed before. This pretty much confirms my suspicion that leaves or some other debris made it's way to the drain tube and wound up flooding the blower motor. I know where the tube ends but I haven't been able to locate it's source in the A/C Box. I plan to reassemble it tomorrow so hopefully I'll find it then.
I noticed that there is a foam filter above the micro filters. I could not see any way to remove it to clean it. Anyone have any suggestions ?

 

[BWV]

They don't all come with the filter installed.

At least that's what the service manager at the dealership told me when I said mine were missing...

 

[Leo Monahan]

I hate when someone is so slick that they think they can feed you any BS and you will just smile and accept it. I would have asked him if oil pan drain plug is optional.

I also discovered that above the replaceable filter there is a foam inlet filter. On the cabin side there is 1 installed but on the outside air side there is none. It seems very odd. The problem I have was caused by leaves or debris coming in the outside air side. I'm thinking that they may have forgot to put that in also, or maybe it is optional too.
Do you or anyone reading this post know if there should be 2 foam filters ?

 

[Leo Monahan]

A little further investigation showed that what I thought was a foam filter actually is the outside / recirculate damper door. There are no foam filters as I previously stated. The only filters are the microfilters on the blower inlet. I still have not found how the leaves got into the fan but if the microfilters had been installed at the factory this issue probably would not have happened.
The condensate drain is located in the evaporator housing not the fan housing as I previously thought and is not accessible from inside the cab.
Aside from learning a lot about the A/C a couple of takeaways from this are;
1. The Field Service Manuals on the NICOclub.com site are awesome.
2. If you buy used parts check LKQ. If you live near 1 of their 4,000 associated "U Pull It" salvage yards the cost is less than 10% of OEM. If you don't live near 1 they have an extensive inventory on-line of parts they have removed. These prices were less than 50% of the cheapest on EBay.
3. You should stop crawling under the dash before you are 68.

 

[texmexpair]

Does anyone know where I can locate the blower motor relay on a 2007 Titan? My pdf manual mentions the relay a few times and even shows how to test it. Unfortunately, the manual fails to mention the location of the relay. I've looked in a couple of relay boxes under the hood and near the battery, but it wasn't there.

 

[danman]

My truck also did not come with said cabin air filters. I'm guessing that since it is a lower trim level, costs could be cut without installing those filters? Funny thing is that the truck is provisioned to accept the cabin air filter, so I put some in because why not?