I am looking at my EVTM right now. It is for a 1997 so I don't know if it would be the same or not. It looks to me that one side of the button goes to hot-in-run power and the other side goes to pin 29 on the PCM. This is on page 23-11 in mine under electronic engine controls. Hope this helps you out.

 

hey thank you! Damn it I have an EVTM for a 98, how did I miss that! I'm at work but will check immediately when I get home. This pre-empts Christmas presents:thanks:

 

Just so that you know what you are looking for, it is called a "Transmission Control Switch in my EVTM. To look in the index, it shows the schematic in like 3 different places in the book.

 

yes, I've spotted it in my EVTM as well. The wording "trans control switch" is what threw me off and the fact that the wires from the button itself are both white. I'm sure that they hooked into the wires you described somewhere, but as I didnt have the complete interior harness I was scratching my head.

Thanks

 

Ok, I've got the wires tied into the harness, (I knew there was a reason I didnt cut all these extra wires out),and for snicks I wired in an LED light from one of the white wires on the Mark OD button to the tan/white. When I hit the O/D button it illuminates but goes out as soon as I release the button, so I'm not sure if it's in O/D or not. Because of weather conditions here I'm not able to take it for a test drive. Has anyone wired in an indicator light in their system to show O/D?

 

I believe the button is momentary just as you described. It just gives the Pcm an input telling it to turn o/d either on or off. The only way that I could think of to come up with an indicator would be to tie into the output from the Pcm to the transmission, but I would bet that you would still only be able to have it come on at speed when the computer calls for the 3/4 shift solenoid to pull in. Maybe someone else has tried to do this and has a solution.

 

The switch is just a momentary switch.
I hooked up the hot wire to the light and the ground wire goes to pin # 55 (Trans control indicator lamp). Mine is a 95 Mark VIII. If yours is a different year it should have a comparable pin.
I used an Autoloc momentary switch with a light ring around the outside of it. When the o/d is turned off, the light comes on until you turn the o/d off.
Mine works perfect like it should.

Kevin

 

I had thought of suggesting that route, but on the later models, the indicator lamp wire goes into the message center which talks to the PCM via the data link. I never mentioned it because I assumed that he wasn't using the message center. I guess I should have asked.

 

Thanks for the help guys. I'm not using the message center. I have tried to wire it in as Kstones suggested but that resulted in burning up the o/d contact that's in the shifter handle. I had a spare shifter assembly so I'll keep trying. Maybe it's not feasible without the message center.

 

I am not using the message center in my truck either. The light wire should have nothing to do with the switch. The light should have a switched power wire(hot in run) to one side and the ground side should go to pin #55(indicator lamp).
The o/d switch should have a switched power wire(hot in run) to one side and the second wire should go to pin #41 (trans control switch).
This is the way that my EVTM book shows it to work for my 95Mark VIII.

Kevin

 

He is using a '98 donor and on the later model years, the light gets its ground signal from the message center, not straight from the pcm. The message center communicates with the pcm through the data link, so I dont know it there is going to be a way to make an "o/d off" indicator work without that message center in the system. I may brave the knee-high snow drifts tomorrow to go out to my shed. If I do, I will look into it a little deeper in my EVTM.

 

I dont know where Aviston is, but we're getting our ass kicked here, so dont get frostbite just for me.

I appreciate all the help guys. As I stated before, it's more of wanting a neat "convienence" feature for my daughter. If we cant figure it out, or if it's determined that it wont work with the 97-98 driveline, so be it.

 

Hi guys, gals
Sorry to bring up an old thread but I need answers to a few questions.
I swapped a 4r70w along with the 4.6L from a Lincoln mark viii.
I have two wires for the overdrive on the trans shifter, If I follow the Mitchell wiring diagram for my 1993 model then one wire should be 12volts and the other tan and white wire from pin 41 of the ecu. this should engage and disengage the overdrive.
Am I right?
Other question, I have a white and green wire coming from the transmission I believe, this should be connected to a lamp to indicate overdrive on and off?


Thanks for your time...

 

Hi guys, gals
Sorry to bring up an old thread but I need answers to a few questions.
I swapped a 4r70w along with the 4.6L from a Lincoln mark viii.
I have two wires for the overdrive on the trans shifter, If I follow the Mitchell wiring diagram for my 1993 model then one wire should be 12volts and the other tan and white wire from pin 41 of the ecu. this should engage and disengage the overdrive.
Am I right?
Other question, I have a white and green wire coming from the transmission I believe, this should be connected to a lamp to indicate overdrive on and off?

Thanks for your time...

According to my manual, the tan and white wire goes to pin 41.
The o/d light should have a power wire going to the bulb and the W/LG wire should go to pin #55 on the PCM. It has been several years since I did mine but this is what I see in my manual. Mine is a 95 Mark VIII so they should be the same.

Kevin

 

Ok thanks
I'll look at it this week end and see if I can get the light to turn on if I press the O-D switch.

Richard