Frozen_Joker, I have replaced the fan speed switch that is in the dash, that was the last thing I replaced. It looked a little cooked...hmm I wonder if the wiring was damaged? But then why would it work intermittently? I will check the grounds to see if any rust might be causing this.
Thanks for all the responses. I will check it out again today.
The diagram is accurate. All of the Fords I have worked on for 40 years have work the way the diagram says.
To each their own good sir. I will take my experience over whatever the Ford manual says any day. If something happened that contradicted what the book said would happen to me, then I am going to roll on that.
I was unaware if you had or not. And you are positive its good? There is a possibility of a nasty wire behind the dash somewhere. Never can fully rule that out. Lol.
Ok, so I finally had time to mess with this again. I pulled out the Blower motor resistor. How do I check it to see if it actually is bad? The thermal limiter is pretty black but do not know how to properly test it.
Ok, so I tested the items discussed in this thread by following this tutorial Part 2 -How to Test the Blower Control Switch (Ford 4.9L, 5.0L, 5.8L).
When I took the blower motor switch out to test I found another harness in there as well (the one on the left). What is this one for? Anyway, it looks like from my testing that the switch is bad, there was no continuity on some of the settings. The resistor tested fine. But what still perplexes me is that sometimes it would work just fine, then quit. Could the harness/pigtail be going bad? The original switch had some burn marks on it.
At this point I'm not 100% clear on your skill level to follow a schematic and interpret the findings as to which component or circuit is giving you the problems. Please know that's not meant to be an insult at all!
The intermittent operation suggests the switch----its not an uncommon problem.
IF the connector for the front only blower looks melted or discolored replace it. Along with the switch these seem to be subjected to high amp loads and tend to fail at some point. NAPA etc have replacement pigtails specifically for that need---give them the application and they'll have or order the right part. Other parts sellers no doubt have these too but I use NAPA quite frequently.
The switch is also available aftermarket too.
The second connector you show in above photo is an unused connector for a rear blower. Without the appropriate dash control pod there's no place for the second connector to attach but it doesn't have any live power in it anyway, not really a concern.
No Worries JWA I am not insulted. I am a novice at this hence me asking these types of questions on forums like this. I would rather try to figure something out myself (with a lot of help from kind folks like you, Sub_Ford, Frozen_Joker, etc) and learn from it than to automatically take my vehicle to a dealer to get it fixed. Being that my E350 is also a 28' motorhome helps in that department for not all dealers can service these things. Like in the Marine Corps, I had to know my equipment but that knowledge did not just happen.
When I first replaced the switch it was burned but the pigtail/harness was fine. I also got a new battery for the beast, crazy cold winter killed the 5yr old one. I think I read somewhere on this site someone experienced something similar after replacing a battery. Anyway I will replace the switch again and see what happens. This WILL get fixed!! haha
Thanks again for your candor and helpful suggestions.
Success!!!! So after double checking all the parts I still had this nagging feeling that everything was good and that a loose wire/connection was the culprit (as subford and others suggested early on). To me, this would explain the intermittent working perfectly fine and then quitting. So I decided to go high tech, I popped the hood turned the ignition to on, turned the blower to vent/med and started wiggling wires under the hood. Well wouldn't you know it the harness/connection to the Relay was loose; Wiggle it and the blower turns on, tap it and it goes off. A quick tightening/re-seating and now the thing is a go all the time!! I guess I felt I did not need to check that area since the part was relatively new. Thanks for all your help and patience guys!! Lesson learned :-)
HI I can't help you with your ac problem, but maybe you can help me. I just drove one I picked up in Va. and drove to Cocoa Fl and it ran like a top some thing you have. But I can not find the fuse box. It is not under the dash like the manual says. Not under the hood the power box is there but not the fuse box. Can anyone HELP? Thanks Jake