So, I tried to search, but this is odd and hard to describe and I didn't find anything, so I apologize if this has been covered previously.

Background- Van is a 1996 E-350, 7.5l with rear AC. The AC died a couple years ago (would not hold a charge), so I replaced a bunch of stuff and recharged recently. Replaced the orifice tube, condenser, dryer, compressor, and o-rings. Had it vacuumed/charged at a shop. It's cold and nice.

But here's the problem... Went on a trip last week, 1000+ miles one way. Drove it pretty much straight through with basically only bio breaks and gas stops. On the way down, after about 12 hours, the rear blower fuse blew. So, the rear blower was completely offline. That's not the odd part. When that happened, the front air suddenly stopped blowing out of the vents. I could hear the front motor blowing, but nothing was coming out of the vents, in any position. When we got down to the destination, I replaced the rear fuse and all was well.

After about the 12th hour again on the drive home, the rear fuse blew again. And, the front blower again stopped blowing. It wasn't super hot, so we were fine with the windows down for the rest of the drive again.

I'm perplexed; it seems almost like the evaporator is freezing or something, and preventing air from blowing? Anyone heard of this before, and have any suggestions? The air was working fine until the rear blower fuse popped. I'm trying to understand the correlation. Why does this cause the front air to stop blowing out the vents? Again, I do hear the front blower operating like it should, and diverting to the other vents, but no air at all comes out.

 

I have no clue about the 96 system but I have a couple more questions to deepen the mystery..

1- Do you have computer controlled climate control or just manual controls?

2- Where is the fuse that blows, back at the rear unit or under the dash?

3- If you replace the fuse and the van has sat for a while, if you start the engine, turn the both AC units on and then remove the fuse that has been blowing, does the front unit immediately stop blowing air from the vents?

1- need to find out why the fuse is blowing...

I have to run but was glancing real quick for a wiring diagram that might fit your van but didn't see one. I did come across some info for a 95 15 passenger van that might come in handy. You should copy and save the info if it is the same system as yours even if it's not addressing your exact problem..
E350: passenger..van..The front air blows cold and the lines..hot air

Unless you have a automatic climate control system, I believe all the vents are controlled by vacuum.

I don't know which van you have but a EVTM would be good to have as it would have all the diagrams in it and they are fairly cheep

1996 club wagon EVTM
http://www.ebay.com/itm/1996-Ford-Ec...item5447801667

 

Thanks for the help...

1.) Manual controls.

2.) Back by the rear blower

3.) With the rear fuse blown/removed, the front blows for a while then peters out, like letting the air out of a balloon almost. The tiny amount of air blowing out the fronts is cold, but it would barely ruffle a feather. The front blower is running at normal speed though; I can hear it. Sounds normal, just no airflow.

No idea yet why the fuse is blowing. Maybe the motor is getting old and the bearings are wearing out. I have no idea yet; tired of driving it so it's parked! 2200 miles in a week got old.

 

may or may not be the motor... from what I have read, switches and connections throughout the circuit can get weak and then the motor doesn't get the current it needs. This in turn causes the motor to draw even more current until the fuse blows or what ever connection is bad fails completely...


You mentioned about the evaporator icing up.. That too could cause the blower motor to use more amperage and perhaps blow the fuse.

The most common cause I know of for the evaporator to ice up is low on freon.

So perhaps the evaporators are icing up. The rear ices up first and the fan pulls extra amperage blowing the fuse. Now I am not positive on this but with the rear evaporator iced up and no air blowing across it, perhaps that causes the front evaporator to ice up faster....

Since you did the work you may have trouble getting the shop to warranty any of their work. Often shops pull the vacuum and don't wait very long before they charge the system. When I replaced my system I left the pump on for several hours and then left the gauges hooked up over night. The next morning it had lost no vacuum so i charged the system..
I do have a very very small leak now (I believe) because I can see where dirt is collecting just under the compressor like the compressor shaft seal might be seeping oil out. That almost upsets me because I almost decided to change the seal before I installed the new motorcraft compressor just because I figured it probably sat on the shelf for a few years!. BUT it is still cooling good a year later...

 

If I've got an icing problem, it probably isn't a big deal, since I won't be taking many 12 hour trips in the van. I can live with that.

As for warranty, yes I'm out of luck. All they did was the vac/charge. It was up to me to ensure that the system was clean and properly oiled. And I'm just a shadetree. I don't know if it was 100% clean.

 

Yea, after 2200 miles I would want to hang around town for a little! Mine had a bad rebuilt compressor on it when I bought the van so rather then try to clean parts and worry about if I did it right or not, I just replaced everything. Later I was looking in one of the old suction lines and saw that it was rusted or oxidized inside and was glad I just replaced it all! Mine is a single front AC and while it keeps me cool up front, it takes a while to cool it down in the back if the van has been siting in the sun...

If they just reciently charged the system, perhaps they just didn't add quite enough freon?
Too much and it wont cool as well as it should. Too little and it will freeze up.

 

You know, I will let them know. Maybe it could use a top off. The shop is good people and I've been using them for years, so they'll definitely check for me. Thanks for all the info.