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7.3 OD Problem

3K views 18 replies 9 participants last post by  dieselmt 
#1 ·
'99 7.3 with auto tans./od. Sometimes after shifting from park, the OD light on the end of the shifter starts blinking. I read somewhere before that the wiring harness going through the steering column moves some when the shifter is moved from park into reverse, drive, and so on. The article said that this sometimes causes the wire for the OD light to short out and cause it to flash. When this happens in my truck if I turn the ignition switch off and then back on the blinking stops. Has anyone else heard of the wiring harness/shorting out diagnosis?
 
#2 ·
Could be that but it also blinks as a sign of tranny problems. and sometimes will reset if you shut down and restart
 
#4 ·
It's been doing this for quite some time and runs fine. I had the trans. serviced by the dealership about a year ago. They said that it was fine, and that the light was a "malfunction", as long as the trans. didn't slip or otherwise act strange not to worry to much about it. Doesn't really sound much like they wanted to deal with it.
 
#10 ·
well most comon reason the OD light blinks is the speed sensor but it can be a number of other things my 98 f150 started doing it when my alternator was getting weak and it went away after I changed the alternator... the od light flash i believe is kind of like a check engine light for any thing electronic in your vehicle and if some one has a good code reader such as snap on or one of the really expensive ones they can actualy pull the electricle codes... its prety awesome when its running the scan your power windows lock and windshiedl wipers will start going crazy but it will tell you whats wrong with it
i ran one on mine because the abs light was on and it told me exactly what was wrong with it
 
#6 ·
If the wire breaks, the truck will not go into OD when you push the button, or will not come out of the overdrive position on the button, but the light will be out. You have some kind of warning code going on, you should take it into a good shop and get it checked out before you start having problems, just to be on the safe side.

Gord.
 
#8 ·
If you hav'nt pulled the steering column plastic cowl to check it then i would highly recommend doing it before commiting the tranny or sensor. Its not that hard to pull it & inspect it. The small loom will move around & sometimes grd. against the shifter arm worse when you move the tilt up & down. Check for a small break in the loom insulation where the wire is chaffing.
 
#9 ·
I'm having this very same problem but my OD button just stopped working period. I figured it was a simple fuse but it's not so it would seem since I've pulled every fuse known to mankind. I tried to remove the steering column cowling but cannot remove the top piece due to the ignition. How do I remove the top cowling without removing the ignition if possible?

Also any other tips/info on the OD button would be appreciated. Thanks in advance.
 
#11 ·
Well wrs8524, all you need to do is turn the ign.to the on position & take a very small screwdriver & insert it into the small hole just behind the r.f. hole where you removed the frt. screw. its the second hole back. Move the screwdriver around till you feel the small button & push in on it & lightly pull on the ign. tumbler assy. till it pulls out. Careful not to damage the little grd. tab. it can be bent to where there will be no more key chime & cause other problems in the modules comunication network. Its not that bad though. The tab can be bent back inward if bent out. 9 times out of 10 it will not be damaged when removing the tumbler. The ign. will be left on but will not hurt anything cause your merely inspecting the harness. If a repair on harness is to be made then you can just remove the grd. cables at the batt's. Good luck!! David!!
 
#12 ·
Ok, so I got his steering column apart and have been checking out wires. No frayed wires, no damage at all. However, on the connector for the OD switch is showing 12V on the top 2 wires. Here is what the connector looks like -

. rd/wht - 12v
. wht/lt grn - 12v
. lt brn/wht - ground

So, I am thinking the OD switch is bad, cause with both leads showing 12v would that no mean the ecu is telling the indicator light to turn on (which is not on)? ANyone have a link to a wiring diagram on this?
 
#13 ·
Well, I just got off of my ford site studying the wsm for your concern & i come into a snag on this one. You need to get those codes before i can proceed. Any scanner you can get a hold of should have a option to test the trans also. It will say eng. & trans. on the option to get the continuous codes. I highly dought it will have any hardfault codes unless it catches it when the lite is acting up. You can't get the hardfaults if the key is turned off & back on. it presets everything until the concern is present again. Another thing can be done also. When scanning for codes try getting all the codes for all the modules. All continuous codes in the menu. Thats what our IDS does. That way you don't miss anything. Let me know & i'll help you get this thing fixed. David!!
 
#14 ·
I'm assuming that you're referring to the original poster's problem yes?
 
#15 ·
Well Clerkend must have got his fixed. He has'nt replied back. This was just a simple solution for diog. tranny problems. The fuse 29 powers the tranny circ. Diesel Nut, did you get yours figured out? For all you guys the first thing to do is get the codes. I have also seen problems w/ the shift selector sw. down on the L. side of tranny cause a short.
 
#16 ·
No. We were working on wrs8574's truck. Checked the OD switch, no short. Replaced it anyways, no workie still. So, here's whats happening -

The truck drives as normal. OD lock out will not work.
OD lock out light will not illuminate.
3 pin connect for the switch in steering column has 2 pins seeing 12v, one is ground.

I am lost. Ideas?
 
#18 ·
Negative.

The bulb is built directly into the TSC switch and as Jason stated I replaced that already. We've pretty much ruled out all of the basics but I will check the #29 fuse tomorrow morning when it's brighter out. So basically I'm begining to think that the shifter on the column is bad since it's showing two 12v wires with correct voltage and with a new TSC switch installed yet nothing works still. It has to be somewhere between point A and point B more than likely.

BTW Jason threw a high dollar code reader onto the OBD II port and it threw not a single code.
 
#19 ·
wrs8574, just take a small mini screwdriver & put it in the second hole back from the hole where the screw holds the cowl in place on the r.s under the cowl. You must have the ign turned to the on position. Push in on the small pin & the tumbler will come right out. Be careful not to bend the ign. grd tab at the end of the hole. The wire runs along top of the column w/ 3 wires in the small harness. For the od issue on the F150's the od harness runs beneith the column so i don't see any concerns w/ them chafing. The fuses are the first thing to check anyway. I just have so many more come in w/ the wires chafing than for any other problems. Sometimes i get one in w/ the solenoid pack shorting but when you pull the pan BOY! does it stink.
 
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