Had a fuse blow out for my trailer lights. Replaced the fuse and for some odd reason now my Speedometer will quit working. When it does the cruise control also quits.. It will come back on sometimes while driving. I know it sounds like either a loose wire or something. But I cant find anything. Truck is a 07 Ford f350 crewcab 4x4 with the 6.0 TD. Any suggestions as to what this could be? If anyone needs more info just let me know.

Thanks for any response..

BTW.. everything else works fine.. Its runs fine and drives fine. Other then what I think is the TPS going out as it has been giving me a few stalls while taking off this last week.

I just bought this truck in Feb and its my first diesel. No mods that I know of. So I think its completely stock.

 

ok its been about a week since the speedometer quit working. or rather quits then works. then quits/works.. Now today I belive the tranny slipped. Was driving about 65mph. Had to hit the gas and it wouldnt down shift at all. Let off the throttle and it did a kinda lurch like a shifting.. This happen also one time while just holding about 65 to 70 mhp.. and one other time it happened right after a down shift while accelerating to 70.
Truck has almost 62k miles. Does this sound like a trans slipping problem? This is also my first automatic. Always had manuals. If its a trans problem its going to the dealer asap. I know the warranty covers it till 80k??

Or could this be related to the accelerator position sensor? As I know thats starting to have problems.

Thanks again

 

Late 06 and 07 trucks have a 5yr/100k on powerstroke engines, and 5yr/60k on drivetrain, so it would be out of warranty. I doubt it's slipping. These transmissions can take a HUGE abuse.

Take the sensor out of the rear differential, clean it off and put it back in. If it looks really nasty just replace it. I've heard of the speedos doing whacky things because of that as well. My buddies truck used to be like this.

 

Thanks for the info. Ill do that today. Also going to replace the fuel filters.

 

$90 for speedometer sensor at Ford.. jezz.. got it in and it seemed to fix it. at least for a few miles.. It started once again. Driving down the road I closed the cig tray and the guage bounced around. so I opened it and closed it again.. bounced around.. did it a couple more times and yup.. bounced around.. Now to look for that loose wire under the dash. .
The lurch seems to be gone now. Went t ford and got a can of the cretane boost stuff. Littel more power also and better take off while cold. Hope thats all it was.

 

I prefer opti-lube products for my fuel tank additives, it was independently tested against 15 or so other additives and was the best for lubricity right behind bio-diesel. If memory serves, the Ford stuff is just Stanadyne, which a TON of guys use, but that was proven to do almost nothing for lubrication. Just an FYI.

Glad you seem to be on the right track fixing that stuff! I can't believe that the cig tray would lead you to that... amazing haha.

 

was going to try the redX stuff I have been hearing about on this site.. Il either get that or the stuff you mentioned next time.

Yeah small wonders of what a cig tray will so.. Especially when its not used. HAHa. Not sure if I found the wire or not though. Its no longer doing it so we will see on this weekends trip up north to dive for abalone. Towing the 5th and all. I did notice there is a set of wires that are spliced into the wires under dash. They dont go to anything either. all end at a big plug in clip. Kinda weird. Could it be a setup for the toggle switch that some models have for the ambulance setup? No toggles on my truck at all and the sticker in pillar dont stat it has the ambulance setup either. Next time IM out Ill get some pics of it.

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oh and btw.. the speed senson was clean as was the gear oil. Looks like it was just poured in .. But the sensor itself had a small hairline crack on the bottom.. Just replaced it. Sure thought it would maybe run about 40 bucks.. NOT $90 from Ford.

 

The REV-X is awesome stuff too, but that's an oil additive, the opti-lube I use is a fuel additive. I use Rev-x as well, and it works wonders.

Get a picture of that harness. If it was factory it wouldn't be "spliced in" anyways. I have the upfitter switches in my 06. Doesn't need to be an ambulance package. You can even order the kit of the switches, the relay and the wiring harness for about $100 from powerstrokeshop.com

$90 is expensive, but nothing on these trucks is cheap.

let us know how you make out.

 

will get both of them..

Still cant find the loose wire.. going to take it to ford and have them fix it.. Now the speedo acts up even when I shut my door. front and rear. I kicked the side steps and the speedo moved.
Starting to sound like a ground wire to me. Ill keep looking till I take it in. Just becoming a pain in the ***. Like to use cruise control. and with this going on cruise control dont work. Waiting to see what happens while towing my 5th this weekend.

 

OK here is some pics of the spliced in wires under dash. Also toggle switch that was installed b4 I bought the pickup. you will see in the pics that the toggle is spliced into a red and a blue wire that comes from a main harness that enters just left of brake. right behind the ebrake.


OK got some pics of wires that are spliced.
Could the spliced wires have been linked to a tuner?
This truck was repoed from Ford Motor Credit and sold at auction where my Brother inlaw bought it for Mayer Equipment in Sacramento,ca. So im sure if it had a tuner on it. Ford would have taken it off right? Got under truck again today to check the wires running to the speed sensor. Noticed the exaust pipes are at least 4 and could be 5 inch. Sure aint no 3.5. Ill douple check later and get more pics of wires and plugin under the dash. Like any numbers that maybe on the plugin or such.