This morning battery was dead, so replaced battery this morning then when I got in the truck I could hear a fan blowing. I didn't even have the key in the ignition yet so it took a few minutes to figure out that the defroster fan was blowing air even thought the truck wasn't running on the key turned to accessory.

Then I started the truck and noticed that the air bag light was on. As I started driving I noticed the speedometer wasn't working either. Then the check engine light came on and stayed on. I also noticed that the running board lights had quit working. As a final problem, the automatic transmission wasn't shifting properly. It would rev the engine about 1,000 rpm beyond the normal shift points and then slam into the next gear. Also my driver window quit, then the rear wiper did also! Now the running lights work occasionally and the DS window will only work for about the first 5 minutes after starting the truck. [/align][/align]Autozone checked the CEL and it was vehicle speed sensor. Could this really cause all these sudden issues? And if so, how easy is it to replace?[/align][/align]oh yeah, 1997 5.4 triton 4x4 XLT about 150,000 miles[/align]

 

I have the absolute identical problem on my 98 Expedition. Did you ever find the trouble?

 

I am speculating here, Is the OD light on the shift lever flashing?
Usually if it is then its a good possibility its a trans problem, vss, etc.
If not , I would suspect the problem is located somewhere other than with the trans.
Suggest checking all electrical connections from battery and alt to inside of vehicle. Have seen some weird problems caused by poor supply connections to inside of vehicle . This includes all ground connections too. Its a good place to start and can't hurt to be sure connections are clean and secure.

 

thanks for the response.

The OD is not flashing. I do agree that there is probably some electrical problem, however, I changed out the VSS (on the rear differential) and everything seems to be working okay although the Air bag light is still on (haven't figured out how to get that one out).

I still suspect that there is a problem other than the VSS, but it's working for now so I'll just be thankful. Interestingly the first replacement VSS I got from NAPA would not fit in the same hole as the original VSS. Parts looked identical but the cylinder was a tiny fraction larger than the original. Got another aftermarket part (The ford dealership was useless in trying to get the part insisting that I was asking for the wrong thing until I brought the original part in. "Oh you want the rear VSS? Oh we don't have that.")

Anyway I suspect with a car this old that there is probably some corrosion in the connector or wiring, perhaps just installing a new part fixed it though.

Thanks again.

 

same issue in a 92 e250...was a blown fuse that runs the dash,radio and trans!!! stupid design but new fuse fixed the hard shifting!!

 

I replaced the speed sensor (VSS) back on the rear differential and that has fixed everything save the Air bag light is still on. (Blinking code 5 - 2). I don't know how to reset the airbag light, but I understand that after a couple of hundred restarts it will reset itself. Dang it!

Anyway I'm still a bit suspect on the VSS being the problem because so many electrical problems went haywire (rear wipers, power windows, radio stayed on after car cut off), then those things fixed themselves and I was left with the Air bag and shifting issue. We'll see if this holds or not.

 

Might I suggest Removing the battery cables from the battery for a few minutes and let everything reset?? I have kind of the same issue except that its a lot of different things than yours, and its only when I wash the expedition...
I have a 2003 Expedition with 4.6Liter and when I wash it or it rains I have things happening like runs ROUGH, the security light on the dash will blink like it does when the ex[pedition is off, the headlights dim when I idle, radio messes up, speedometer goes crazy, it will actually die for just a split second and then restart itself...
All of the electrical sensors, and modules, miles of wires, it could be anywhere or anything.. I have already spent 1,000.00 on JUST diagnotics and still havent found the issue... It has been a great truck, and I hate to trade it in.. but at this point I have no idea how or where to start diagnosing the problem myself....

 

Suppose you consider this; take a spray bottle with just plain water and try spraying a small section at a time. Just maybe you will be able to isolate the problem area without washing the entire vehicle. How you do this is up to you. You could try it with the engine idling and lights on and observe for any change as you spray individual areas.You might want to go slowly in order to give the moisture a chance to do it's thing. What do you think?