Just recently purchased a 2001 Excursion Limited 7.3 2WD. The OD button doesn't work. It doesn't light up at all and if the transmission is actually in OD it will not downshift. But that's not really a concern to me as I don't tow anything but my kids. The problem I am having is that the transmission will only sometimes shift into OD. When it is shifting it works fine, but sometimes it just won't shift into OD regardless of load and speed. Anybody has any pointers or suggestions as to what direction I should go in trying to diagnose this problem? Thanks

 

Whats the mileage on the truck/trans?

All the shifts are good other than an ocassional no O/D shift? You mean when the O/D shifts are there/working, the cancel button then works?

 

Even when the OD shifts fine the button still doesn't work. The truck has 98k miles.

 

As a 'first step'.. I'd check for power distribution out to the O/D cancel button.. The fuse (#19 10amp) should be good since there's other circuits/components that would have been affected if an open fuse.. Remove the shifter end cap (pops off) and pull the cancel switch out of the shifter/connectors.. Check for Key/On 12v applied to the switch.. The defaultkey/on/run is forO/D function, but ocasionallythe shifter/OD control wires will scrub/cut through from wear being pulled over the column or at the shifter base and can short the control wires.. May not be the problem here, but if there was a unit problem, most times you'll have a O/D light 'flash' indicating a problem.. Could be other issues/components, like the PCM ect, but since the O/D won't illuminate I'd look there first..

 

Thanks, I'll check into it in a minute.

 

Well there is one pin that has 12v. I tried another switch from a F150 and the same thing, no light. Maybe one of the other two wires might have got cut or something? IDK
But I just remembered that the PCM has been flashed with a Diablo Sport Predator with a 80hp 180tq tune. I redid the tune but with Stock shifting settings just to see if that would affect the OD. So far so good with the OD shifting but I don't know if that fixed it just yet. Thanks