OK...so called my local shop today and they referred me to a local transmission guy. He was kind enough to provide some feedback on my diagnosis. 1) It is likely not the Neutral safety switch. Ford put them inside the transmission when the built the Torqshift to eliminate the problems they were having with them on the outside. Rarely does it go bad so replace this only as a last resort. 2) Likely issue is wiring and it is either in the wiring harness entering the transmission (check the bundle coming into the transmission after you drop the pan) or check the wiring harness coming down on teh right side of the car (passenger side) by the manifold. If it comes loose it will melt on the manifold and over time short various wires out. These two issues are common and should be focused on first before tearing apart the neutral safety switch. nice of the guy to provide all this information. More to come (with a solution) I hope.

 

No Crank Mystery Solved

I have been posting my progress of solving a transmission (limp mode) issue and no crank issue (could jump it). Wiring diagram takes one to the neutral safety switch (but local guy told me this was not likely the issue) and I should focus on wiring (melting on the passengers side or chaffing in the inlet to the transmission.

Checked all the continuity this morning and found nothing...even checked the fusible links and they are all fine). But I remembered that others had talked about clutch fan. I had ignored this as I could not understand how a vehicle with the clutch driven by the engine would need a sensor. (I thought it was a standard heat driven clutch but now see it has an electric clutch that is connected to the fan. But this morning I noticed the plug on the fan shroud so I unplugged it and magically the truck now starts. Wow! My tow haul light is off but I have not driven the truck yet so will have to see if that problem is solved.

Thanks to all who have provided some clues (not in replies as I have not had any) but who have taken the time to write up what they found. I hope this will be useful to someone else as well.

If anyone has a link that shows how to replace the sensor without pulling radiator that would be appreciated. Also can I replace this with a mechanical driven fan without causing other electrical issues (it just seems a mechnically driven fan (without the electronics) would make much much much (did I say much) more sense. Any info is appreciated.

 

thanks for being so persistent and updating despite the lack of replies

 

Bullet proof diesel has a adaptor to fit the 7.3 mechanical fan clutch. Glad you got her running.

 

Thanks. I will take a look.

 

Here is the link

http://www.bulletproofdiesel.com/ProductDetails.asp?ProductCode=90201099

 

Glad you got it figured out. I am guessing that there's some sort of "safety" feature to ensure that without the ability to cool with the fan (a necessity in TX), the truck bypasses the starter. Now in MT, I don't think the fan clutch ever engaged in my Excursion...at -55 below and the fact it was already a cold blooded beast, I am betting the fan got rare usage. Now my 6.4L on a 104 degree day with the A/C on, climbing hills you can hear the roar of the fan come on. My 6.0L always pitched a fan clutch code yet it worked as it should. Was fixing to tear into it and replace the peeling grille at the same time and on the way home to order the grille the truck was totaled when a man ran a stop sign.

As already said, thanks for updating this. I know for me, the fan clutch is not something I would have considered especially with the tow/haul light flashing. Usually that means there is/are DTC(s) stored for the transmission.

Just out of curiosity, did you ever try to have it read to see if any codes were present?

 

Awesome thread. Same thing happened to me, I'm hoping i can drive the same results by unplugging the clutch fan. It will be comical if this is the problem, i just recently replaced the radiator.

 

I am going to try this on the weekend, as I think mine is doing the same thing. Could this be why the truck all of a sudden loses all gears and just revs because the truck thinks its going to over heat? Mine did not start as well after losing all the gears as well but would start if I A.) removed the batteries and put them back on. Or B.) jump start the starter circuit. Thanks for updating what fixed you problem.

 

So i unplugged the Fan Cluth, and gues what?! It starts and i have no transmission lights on.

 

So are you going to replace the fan clutch or just leave it unplugged?

 

I just got around to ordering a new clutch today. I'll let you know if the new clutch causes any problems or not.

 

Sounds good. I will be doing the same thing here in a couple weeks. Keep us updated and thanks.

 

So my new fan clutch came in and I started playing with it last night. I connected it to the vehicle harness and tried stating and it was successful.

 

This is good news to me. I will be ordering mine next week. So no problems going into gear or anything?

 

It seams to be fine so far.