i have a 2000 chevy blazer with about 116k on it sat for about a yr. recently got it going 3 weeks ago been running fine. took my daughter to school in the am and went to pick her up in the pm the speed o meter wont leave 0 and it seems the truck is in one continous gear. now im ur avg backyard mechanic so i aint ya know (in the clouds) when it comes to vehicls but this has me stumped. im thinking the way the speed o meter just went to 0 and with it seeming to be one continous gear that its not the tranny and something eletrical.... o frigging woo hoo i see dollar signs right? anyone got any input? the closest autozone is like 25 30 miles or so and i cant exactaly drives 20 mph the whole way there ya know? lol

 

VSS (vehicle speed sensor). It will be located in the housing directly ahead of the rear driveshaft.

You can try removing it and cleaning it, but if the speedo just went dead, chances are it's toast. But inspect the wiring harness thoroughly first.

The P0502 - VSS (vehicle speed sensor) Low Input post will give you the testing that can be performed to check the various potential causes.

 

lol ya know i was just looking at a link u posted for another poster for symptons and fixs for trannys and thats what i come up with was the vss. what do u think the chances r of getting the old vss out without snapping it of in the transfer case cause it looks a little rusted in there. soak er down with pb blaster and let er sit for an hr or so? cause im affraid if i snap it off in there its buy another transfer case ha

 

On the rear output shaft of the transmission, passenger side is the vehicle speed sensor. Check the connection, look at the harnesses. If that sensor went south or if there's a wiring problem with it you'd have 2nd gear only. That's one possibility....... To check if the sensor is bad jack up one side of the truck in neutral, hook a digital A/C voltmeter to the sensor and turn the wheel up in the air by hand. You should see about 1/2 a volt.

 

my vss is on drivers side transfer case right ahead of the drive shaft i have power all day long if i shift it into 2nd gear manually any other gear goes to limp mode. if the sensor is bad it will read 1/2 volt?

 

No if it's good it'll read half a volt while turning the wheel and drive shaft. A bad one will read little or nothing.

 

ok thanks a million im gonna get out tommorow and check things out and ill post how i make out thanks again!!

 

where is the sensor location

 

Which sensor are you inquiring about?

If it is the VSS, that has been covered:

 

VSS is on the passenger side. There is another sensor on the drivers side which is the rear propshaft speed sensor which is used by the transfer case controller to apply Auto 4WD (if your truck has it) and determine transfer case problems. There's a front propshaft speed sensor too, but the VSS is your speedometer and transmission controller.