O/D switch stopped working

[dock]

Any ideas?

When I hit the overdrive switch on my shifter, I get no light, and no change in RPM. I found a few threads regarding a flashing O/D light, but nothing where it just stopped working. Is this a fuse? Or something more serious...

Thanks in advance,

-Jake

 

[budwich]

The light gets its "instruction" (ie. grd) to light from the PCM module. Of course, the PCM module gives this "instruction" based on sensing that the switch has been depressed. Either that lead to the PCM module is broken or as you suspected, there is also a fuse in the interior fuse panel.

 

[dock]

Thanks for the info bud, at least I know where to start.

 

[Xzibit A]

start by taking off the steering cover shroud, and looking for a borken wire at the sifter boot, ive found a couple of those, if you dont find any broken wires its probibly the swich and you have to replace the shifter handle to get the switch and wires.

 

[sparky2263]

^^^^^^ ditto

 

[dock]

So there's no fuse that could be blown that controls this?

I took the shroud off; there's a single grey wire that comes out of the shifter. It seems intact. So a new collumn shifter is the next step?

 

[Xzibit A]

there are 2 tiny wires in the grey cover, and there is no fuse, if its not the switch its the computer

 

[budwich]

as I indicated there is an fuse in the interior fuse panel. As someone else indicated there is two wires running to the switch. Check these with a multimeter (unplug at harness) when you depress the button to see if you get a "short condition" (ie. switch closed).

 

[dock]

there is no fuse

as I indicated there is an fuse

I'll check it out once more, then off to the shop. I need the power
Not enough consistent facts yet in here for me to keep messing with it.
I've checked every fuse in the side panel, as well as under the hood just in case .

'bout time to buy a Chiltons....

 

[KC's Ford]

I had to do what Xzibit A wrote, and replace the shift handle.

 

[frickea86]

Alright, its time to bring this thread back to life!

I am having the same trouble with the O/D Switch not working when i want it to. Every now and again it will work but not all the time. So i have my ford manual cds and ripped apart the dash and went to town with my meter got nothing, everything is work as it should from where the O/D switch plugs in under the steering column. Then i went on testing it the whole way to the computer, everything seems to be ok, so do i have a bad computer or am i missing something. O/D light is not burnt out or anything, i know this because there is no change in rpms when O/D is engaged and like i said above every now and again it will work. I'm really hoping to no have to take the truck to ford an have them charge me out the butt for something simple.

Any help is well apreciated!

 

[budwich]

What did you test??? Are you getting a grd coming from the PCM to the instrument cluster display to allow the light to happen?.... in conjunction, do you have battery coming in to cause the light to display? If you are not getting the grd, then the PCM ain't happy. If you are getting grd and battery on the appropriate pins, then the light has to light as there is nothing else "in the way".

 

[frickea86]

What did you test??? Are you getting a grd coming from the PCM to the instrument cluster display to allow the light to happen?.... in conjunction, do you have battery coming in to cause the light to display? If you are not getting the grd, then the PCM ain't happy. If you are getting grd and battery on the appropriate pins, then the light has to light as there is nothing else "in the way".

i got all good connectivity from the pcm, and the ground at the time worked, so i have no idea, i think it would be a bad ground if it works every now and again.

 

[budwich]

Hey frickea86.... I suspect your problem is still associated with your switch although it is possible that the PCM is having problems. BUT... first off, your light not working is a symptom of another problem elsewhere and from the sounds of things, the PCM is not sending a grd all the time (at least when it should). Like you I only have the ford cd.... it doesn't really describe the PCM operation much for this area.... BUT... again from the "simple" stuff in the diagrams, it "appears" that the "sole purpose" of the PCM, in this operation is to detect the "action" of the switch on gear shift. My guess is that this "momentary contact" isn't happening as expected by the PCM for whatever reason even though you are able to measure continuity ( I hope that you only measure continuity during the depression of the switch... right???).... besides continuity you do need to see 12v thru the contacts as this is the signal that the PCM is expecting. I guess my last question / comment is .... when you do have O/D, does it function correctly ie. gears shift correctly, rpms are as expected etc.... does it ever flash which is supposed to indicate a problem with the actuators (solenoids???)? Sorry I don't have much better help but it sounds like you are close to ruling out most stuff.

 

[frickea86]

its alright budwich, the o/d works correctly and i am only getting continuity when the switch is depressed, but i do not think i am getting 12v, it was like 4 or 6, it varied, thought i was being stepped down somewhere. Would the PCM not be getting a good ground, i know this would cause a change in voltage or no voltage at all which i was getting off an on.

And i second the fact that FORD Diagrams suck!!...well thats my opinion...lol...thank you again for the help!

 

[frickea86]

also do you have a remedy for a the cold/hot air mixer box?...lol did the little trick already that should of fixed it still broke, only hott air comes out, so it looks like the dash will be comming out soon.

 

[MountaineerGreen]

I dont know if this will help much, but my 01 has a fuse for the OD button. I know this because I took it out, but it in the wrong spot in the fuse box. I traced the wire all the way down, everything checked out OK. Then after about 4 hours of work and testing and putting back together, I found the fuse. PITA

 

[budwich]

Hey frickea86.... not sure about how you determined your 4-6 volts (ie where are measuring points???) but that's your problem. There is no step down.... if your "grd reference point" for your volt meter is poor it might not give you a good reading but it is also likely that your reading is correct. That may mean a problem with the fuse (partially blown) or a poor connector / contact somewhere along the switch path.

On the air side of things, do you have the EATC system and conventional heater / AC?

 

[frickea86]

i've checked the fuse multiple times and have even replaced it, still no go. I'm just confused how outta no where it stops working, like my dash or anything with the pcm has been touch in over probly 10 years, and its all worked flawlessly. I may tear into it today do a few more tests to make sure i was getting an correct reading. I'm hoping its a bad ground or a connector is curroded.

the air thing, it is the conventional heater/AC no fantsy stuff on mine. The reason i know its probly the mixer box is because of when i want a/c, i can't put it on just a/c and turn it to cold, doesn't work, i still get warm air. If you turn it to MAX then that turns off the coolent coming into the box and wala you get cold air.

 

[budwich]

you appear to be well on way.... there are a couple of places along the way in terms of power... a splice and a couple of connectors.... you basically need to check those again along with cleaning I guess. On the ac side of things, from the threads that I have seen basically, it appears that the little "knob/spindle" that turns the door is the culprit and I guess you need to watch it in operation to see if it turns. I think that I have seen a couple threads where people took things apart and found that the door binds on things.... that and the vacuum motor for the panel door had a poor vacuum connection on one side causing some problem.

Ah.... looking at the service section of the CD, I see that the temp section is done thru a "variable resistor" towards an actuator that turns the blend door....hmmmm what are the odds that "low voltage" there results in less than good results.... does this sound familar with your O/D.... too bad the electric circuit info shows a "box" for this.... or I am not looking in the right place. I would measure the resistor on the temperature controls to see if they are "resistive" as expected and then also measure the voltage that they are being feed by.... the diagnostics in the service section has some suggestion for measuring things... it appears that you only need to get at the environment controls and not the whole dash / vent system.