# 99 250 super duty problem



## ken119 (Oct 27, 2006)

Just bought the truck on thursday. drove it home wife takes it for a ride, service engine light comes on speedometer quit working seems like it is shifting hard and the horn chirps every once in a while. Oh, the factory radio doesn't shut off with ignition. I read in a forum that the rear sensor could be throwing a code to create all this havoc. I am going to bring it to a local parts store to run the code. Any ideas on the problem? 6.8 v10 100K miles. Maybe I shouldn't let the wife drive it!


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## Ggg6 (Oct 14, 2003)

When you say "the rear sensor" what exactly do you mean? The only rear sensor I can think of would be the rear ABS sensor, I doubt it would cause all those issues.


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## Sydenstricker Landscaping (Dec 17, 2006)

I think he means the speed sensor, which is I beleive mounted on the rear differential.


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## haybaler (Apr 6, 2007)

Ya the speed sensor would screw up the shifting and speedo. nothing to do with the radio or horn though.


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## Ggg6 (Oct 14, 2003)

Yes I agree thats what I was thinking too. I didn't mean ABS sensor.


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## nevrnf (Oct 12, 2005)

The radio does not turn off until you open the doors after the ignition is turned off. Also the power windows will do the same.


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## DeereFarmer (Dec 12, 2005)

Check out this forum. Everything you would ever need to know is there, and if it isn't just ask!

www.ford-trucks.com


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## ken119 (Oct 27, 2006)

I was told it could be the vehicle speed sensor. they say it is at the rear of the trans, but I still can't find it. As for the radio, it stayed on as if it was hooked directly to a 12 volt lead wire. It would stay on all night if I did'nt shut it off manually. So I disconnected the pos off the battery and reattached so it would clear all the codes. Works fine now. Still looking for the VSS.


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## SuperDuty (Jan 25, 2006)

I have a 99 also, you need to take it to a mechanic and have them reset the codes! I have had the problem when it's cold out...tranny doesn't shift right, speedo doesn't work and the abs light stays on! Mine would go away once it warmed up, but to get the speedometer working and the abs light to clear, I hadto take it to my mechanic!

Good Luck!!!


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## ken119 (Oct 27, 2006)

SuperDuty;390180 said:


> I have a 99 also, you need to take it to a mechanic and have them reset the codes! I have had the problem when it's cold out...tranny doesn't shift right, speedo doesn't work and the abs light stays on! Mine would go away once it warmed up, but to get the speedometer working and the abs light to clear, I hadto take it to my mechanic!
> 
> Good Luck!!!


I was going to bring it to a ford garage for that reason and to make sure everything else is up to par.


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## SuperDuty (Jan 25, 2006)

Was ir private sale or from a dealer? Either way I bring it back to them and see what they know about it, more so if you purchased it through a dealer!! Also a Ford dealer will charge you big bucks!


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## ken119 (Oct 27, 2006)

It was from a dealer about 3.5 hours away. Tried to call my salesman, but he doesn't call me back. It was from a big dealership not a small outfit. I am going to continue to call him till he calls me back, just to tell him the service after the sale sucks. The sensor only costs $25 so it wasn't a big deal.


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## SuperDuty (Jan 25, 2006)

What you need to do is call and ask for the used car manager or the dealer manager and forget the salesman. he made his money and could give a poo about you!


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## SuperDuty (Jan 25, 2006)

Let know how you make out!!!


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## ken119 (Oct 27, 2006)

The speedometer started working after I took the positive cable off, but I bought the speed sensor anyway. Didn't put it in yet, just waiting to see if it happened again. Other than that truck is working out just fine. It will pull more than we will ever think of pulling. The dealership sucks for service. I guess its my turn for a little bad luck. Love the truck. I'll get my wife to put pictures on here as soon as I can. I am probably the only 36 year old that doesn't know how to do that!


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## f250man (Jan 28, 2005)

My 99 did the same thing it was the sensor in the rear diff that was making it shift hard and the speedo not work until you reached 35 mph. It cost me 11 dollars at the ford dealer and about 5 minutes to put in. Steve


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## ken119 (Oct 27, 2006)

I took the pos cable off for about 5 hours. After that everything was fine for about 2 weeks, until today. So I changed the vehicle speed sensor still the speedo was going up and down, trans shifting eractly. Brought the truck to a Ford garage, they said it could be bad connections that are below the brake resevoir. I checked that, used dialectric grease on the connections still nothing. So I had the pos cable off for the last 5 hours, drove it and everything is fine again. I know I am erasing the code, but could it be a bad new sensor that I put in. They did say the vss was working when they had it on the scanner when driving. But I just wondering if it is a bad vehicle speed sensor even though I replaced it with a new one. I don't want to go too deep into something that could be so simple, but could it be Abs module?


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## ken119 (Oct 27, 2006)

This morning I was thinking, what if the diff fluid was dirty could this cause the speed sensor to operate wrongly. So I checked the new sensor that I put in after about 100 miles or so. It had a greasey black film all over it. I cleaned it off, put it back on and it started shifted fine. So I changed the diff fluid (it was black and probably original) after that everything is fine. Go figure, something simple like that could cause so many problems. Hopefully the problem is fixed.


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## ken119 (Oct 27, 2006)

Well that wasn't the case. I talked to a ford service manager. He said to spray the outside of the truck with a garden hose. Sure enough the water was coming down the clearance lights all the way down the side of the cab ending on the fuse box. Therefore, shorting my problem out. Hopefully the problem is fixed. If it is I think I owe that service manager a steak dinner (he didn't charge me anything).


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