Overdrive button blinking "off"

Reply Subscribe

Thread Tools

Search this Thread

Oct 30, 2008 | 08:42 PM

Helene

Thread Starter

New User

Joined: Oct 2008

Posts: 6

Likes: 0

Overdrive button blinking "off"

Hello all

I have very limited knowledge when it comes to anything mechanical--eh..so I am seeking help. I have a 99 Ford 350 Dually. Just today, going up a hill, the overdrive light started blinking "off" and my speedometer is not working. Everything else was fine. Gauges ok, shifting ok.
Any ideas? Is there a way of testing to get the troubleshooting codes yourself? Any help is appreciated.

Oct 30, 2008 | 10:06 PM

rbaker6336

Post Fiend

Joined: Feb 2007

Posts: 7,191

Likes: 4

From: Blairsville,Ga

Could be VSS or vehicle speed sensor on transmission or on rear axle
mine done that on occaisions and was the one on rear axle
it is located right of center on top of axle tube

Oct 30, 2008 | 10:08 PM

WhëëlMå1

Super Moderator

Joined: Oct 2002

Posts: 8,547

Likes: 6

From: MA

Welcome to FTE. I know places like Autozone should be able to read your codes for free.

Oct 30, 2008 | 10:10 PM

BPofMD

FTE Legend

Joined: Jul 2005

Posts: 65,938

Likes: 1,432

From: Millersville, MD

I agree with the VSS diagnosis

Oct 30, 2008 | 10:21 PM

Helene

Thread Starter

New User

Joined: Oct 2008

Posts: 6

Likes: 0

Blinking overdrive "off"

Thanks all. So, would it be safe to drive it to a shop or is there a chance something will "blow" on the way? I am about 35 miles from town. Does the "overdrive blinking" relate to a lot of codes not even related to the tranny? I sure hope the VSS is whats going on. Thanks much again.

Oct 30, 2008 | 10:38 PM

micchicken

New User

Joined: Oct 2008

Posts: 7

Likes: 0

From: Eliot Me

Mine has done that once pulling a boat out of the water up the ramp while turning in 4wh. I heard a little thud, the od light started blinking. I took it out of 4 wheel and turned the truck off. Started back up and all was good. Is yours still blinking?

Oct 30, 2008 | 11:17 PM

Helene

Thread Starter

New User

Joined: Oct 2008

Posts: 6

Likes: 0

I just started the truck up and the light is no longer there. It is too dark out to check the fluid levels etc but I guess the light being out it good. Do the codes/lights just go out like that?

Ford's 2001 Explorer Sportsman Concept Looks For a New Home

Verdad Gallardo

10 Best Ford Truck Engines We Miss the Most!

Joe Kucinski

2026 Shelby F-150 Off-Road: Better Than a Raptor R?

Brett Foote

2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!

Michael S. Palmer

10 Most Surprising 2026 Ford Truck Features!

Joe Kucinski

Top 10 Ford Trucks Coming to Mecum Indy 2026

Brett Foote

5 Best / 5 Worst Ford Truck Wheels of All Time

Joe Kucinski

Ford Super Duty: 5 Things Owners LOVE, 5 Things They LOATHE!

Joe Kucinski

Every 2026 Ford Truck Engine RANKED from WORST to FIRST!

Michael S. Palmer

The Best F-150 Deal of Every Trim Level (XL through Raptor)

Joe Kucinski

Oct 31, 2008 | 12:16 PM

Mark Kovalsky

Frmr Ford Trans Engr

Joined: Aug 1999

Posts: 24,695

Likes: 2,616

From: SE Florida

The light will flash whenever the PCM sees something wrong. As long as it sees the error it will continue to flash. If there error is no longer there it will stop flashing. There is a code stored in memory when the light flashes. It will stay in memory for about a month after the last time the light flashed.

Autozone can't read Ford transmission codes, so don't waste your time there. You'll need a good trans shop or a Ford dealer to read the codes.

Most likely you have a failing vehicle speed sensor. It's developing an intermittent open circuit. You can drive it like that with little risk of damaging anything else. The sensor is cheap, usually less than $20, and it only takes one bolt to change it. It might be worth the risk of just installing a new one instead of paying someone at least 1/2 hour labor to read the codes.