Overdrive won't shut off with switch

[treuland]

The overdrive won't shut off by pushing button on 1999 V-8 xlt explorer. Trans seems to be shifting OK but I occasionally tow and would like to shut off OD. I think the switch toggles the OD off and on from other postings, maybe switch is broken? How best to diagnose/fix? Do I need to replace shift handle and switch?
Terry

 

[Mbrooks420]

Do your reverse lights work? There is a fuse common to the OD switch,and the backup lights(I think its number 27 on my Mounty). I had a problem where my wire inside the sifter stalk wore through, and would occasionally arc out, and blow the fuse. When it happened, no backup lights.

 

[treuland]

Hey, Thanks. It is #27 and it's blown. I was looking at the fuse list but wasn't sure which it was. Now I see it is "electric shift." If short is inside the shift handle shouldn't be too hard to fix if can get it apart.
Terry

 

[Mbrooks420]

It's real easy to get to. A few phillips screws on the bottom of the steering column cover, and unscrew the tilt wheel lever. It can be a little tricky getting both halves of the column cover off, but you only really need to pull the top. There will be a wire going onto the gear shift stalk, and a wire clip thingy holding it in place. My break was real close to the stalk, but pulling on the wire slightly gave quite a bit of slack from inside the stalk. The wire in mine was a little beat from not having insulation for a long time, so I had to cut, and re-solder it. A piece of shrink tube and some electrical tape, and back in business.

I failed inspection for this, and tore out the WHOLE interior, and checked over the ENTIRE wiring harness. Took 2 days. Ended up running the reverse lights on a switch for years. One day I put a fuse in (probably larger than called for) and shifted the truck. A nice smoke show came out of the wheel cover, Bingo. I had done this when working on it the first time, but no smoke/smell.

 

[treuland]

Thanks, hope I can locate the short easily without the smoke! But maybe that's not so bad. I'm going to stick a new fuse in and see what happens. Perhaps it's intermittent and can be reproduced by wiggling the right wire. Seems like that shift lever area is likely candidate as it gets moved a lot.

 

[Mbrooks420]

Mine would be fine until I shifted out of park. When the lever moved the bare wire grounded out against the stalk. Once your in there it should be fairly obvious. All else fails, toss in a 20 amp, and follow the smoke.

 

[treuland]

Well I opened up the column cover and looked at the wires, what I could see looked OK. I replaced the fuse 15A (original) and everything worked OK, backup lights and OD switch and light, even with shifting and moving shift lever. So guess I've got an intermittent, still possibly in the shift handle I suppose. Maybe I'll just give it a while and see. Perhaps my manipulation of the wires stopped the short (temporarily?). Or something scared the gremlin away!

 

[Mbrooks420]

I've snapped fuses before, and never had to replace them again. Maybe you'll get lucky.

 

[treuland]

Lets hope so. Again thanks for your help!

 

[clsale1999]

I had this exact problem on my 95 Exp XLT. No OD lockout function and No backup lights. I replaced fuse # 26 which was blown and the problem was resolved. After reading about OD shifter wiring issues in the steering column I decided to find the frayed wires before the fuse blew again. Here is a great video about how to remove the steering wheel clam shell and remove the shifter boot and releasing the OD wire clip. . I inspected the OD shifter wire thoroughly at the top of the column with a magnifying glass. I could not find any frayed wires that could possibly be shorting out and blowing the fuse. Some of the jacketing was worn but the wires were fine. I then dropped the steering column and traced the OD shifter wire to its source under the dash. No frayed wires in the lower column either. The OD shifter wire terminates in a clip beneath the dash which is easy to get at once you remove the knee panels.
So for now my OD shifter button and backup lights are working. The question is how long. If the fuse blows again I'll disconnect the OD shifter wire under the dash to isolate the OD shifter wire from the system and see if it blows the fuse again.
Thanks to Mbrooks420 for suggesting that the backup lights might be part of the problem. I never noticed they were out.

 

[Mbrooks420]

You can fix it without removing the wheel. Did you check the wire inside de of the shifter? That's where I've always seen them fail.

 

[clsale1999]

You can fix it without removing the wheel. Did you check the wire inside de of the shifter? That's where I've always seen them fail.

Yes, I inspected the OD shifter wire thoroughly at the top of the column with a magnifying glass. I could not find any frayed wires that could possibly be shorting out and blowing the fuse. Some of the jacketing was worn but the wires were fine. I then dropped the steering column and traced the OD shifter wire to its source under the dash. No frayed wires in the lower column either. The OD shifter wire terminates in a clip beneath the dash which is easy to get at once you remove the knee panels.