OD Off light flickering?

[METM95]

My overdrive off light is flickering at times when I start my car and drive it. It is actually controlling my transmission shifting it in and out of 3/4th gear. I tried to resolve it by unpluging the OD button, this worked, at least I thought until today when it flickered again for about a minute.
I know that losing OD is a sign of tranny failure but does the light do this when it is happening? The tranny shifts hard from 1-2 but only for the first time after a long sit, otherwise it is smooth.

Should I be concerned about the flickering OD light in relation to my transmission or is it an electrical thing?

Thanks

Elyse

 

[BobC]

Drove my car today with the o/d off and also saw the light flickering. Just figured it was the alternator kicking in and out as it was just under 2k rpm's, although it may be related to my intermittant charging problem. Wouldn't just assume it was your tranny going bad as mine has been recently rebuilt and shifts firm all the time.

 

[CheckerSHO]

Flickering or flashing? a steady flashing OD light means there is a transmission problem...at least on OBD-II fords.

 

[METM95]

It flickers initially upon starting, continues to flicker on/off for a few minutes, then goes off. It is not a constant flash like if it were an airbag light or something light that. That is why I originally thought it was just a bad od switch or bad shifter ****. So I disconnected the od off button completely. It only happens once every few days to this point. Very odd though. Not sure what to think or how to proceed as my check engine light is not on.
?????

 

[METM95]

oh, and there is no pattern to the flash either.

 

[CheckerSHO]

Sounds like a wiring problem. Given that the wires for that switch get moved around alot near the shifter, they may have gotten caught up in some metal and shorting together or to ground intermittently. The OD switch, from looking at a wiring diagram, sends 12v from fuse #18 to the PCM when you press the switch, and it only does it when you hit the switch(momentary contact switch). It also looks like that OD light is a separate circuit, controlled by the PCM. It only comes on if 1)OD is turned off or 2)there is a transmission problem. Given the intermittent nature of the problem and the problem happening with the switch disconnected, i'd say its a wiring concern. With the wiring diagrams Bizzy has posted you should be able to test the wiring if you have a voltmeter. If you want to follow thru with testing the wiring ill help as much as i can also

 

[METM95]

Well, I just got back from a drive in the rain, and the light stayed off when I started the car. It did however come on during my drive and stay on until I shut the car off. It didn't come back on again after re-starting and leaving the store and stayed off the entire drive. Now I am mega-confused. Car is shifting well and due to the fact it didn't come on again, would lead me to believe it is more of an electrical deal, but I need to figure it out so I can drive to work on the hiway without running in 3rd only if the light comes on again.