I am out at a softball game, on the way here I noticed my speedometer was not working at all. The transmission went to acting up and the overdrive light on my gear shifter started blinking. Could I have blown a fuse somwhere to cause this all of a sudden? If so does anyone have a book that could tell me which fuse? Or do you think my transmission has just took a dump on me?

 

fuse 18 controls : Electronic Shift Module 4WD, Speedometer, Air Bag Restraint, Automatic Transmission Shift Interlock, Automatic Day/Night Mirror Overhead Console (Bronco), APCM (Diesel)


other issue it could be is the VSS in the rear axle took a crap and is no longer working. the transmission has no speed to imput in the computer to shift, so thats why everything is blinking.

 

Theres an electrical module on the top of the rear pumpkin, disconnect it, clean it out with some contact cleaner and reconnect it, usually fixes the problem your describing....

 

Thank You guys so much. Matt, I did pull the fuse out and check it. It is a 10 amp fuse but is it still good. I will take the module apart tommorrow or Monday and clean it out really good. Till then it will have to be parked in the driveway. Thanks again.

Dustin

 

There are actually about 3 fuse in that fuse panel that are tied into speedo/trans control but they are not labeled as such. Pull every fuse and check it.

 

I will go through them all then Tim. Thank you guys so much for all the help. I really love this board, any problem I have had since I got this truck has been solved on here. All I have to do is write up what I have and the Technicians on this board go to work. Thanks!

Dustin

 

Make sure you pull the VSS out and clean it, not just pull the connection. =)

I'm not sure on what you are supposed to test them with though.

 

Make sure you pull the VSS out and clean it, not just pull the connection. =)

I'm not sure on what you are supposed to test them with though.

 

I am not familliar with the VSS. Could you explain that a little more for me?

 

Ifyou look at the rear end of the truck, on the pumpkin towards the front there is a connector that is bolted in with a 8 mm or 10 mm bolt. that is the VSS (Vehicle Speed Sensor)

 

It is basically a magnet that sits on the rear pumpkin that reads teeth on the differential to tell if you have wheel slip to control RABS system and your speed, as well as shift points for the AutoTrans.
The auto trans also has the TRS - Transmission Range Sensor which helps with shifting.

The do go bad, but your speedo not working correctly points us to the VSS.

 

Wouldn't it go into limp mode if one of the fuses were burned out, due to no reading from the VSS or TRS?

 

Yes that is what its doing. OD light flashing, hard shifting......

 

Could this same problem cause the ABS light to come on in the dash? It is on also but it has been on for a week or so.

 

Yes and like William was saying the VSS on the rear diff could do it too.