i had a head light switch meld down on me and melt a tone of wires together.....so i figured it all after some minor frustration
so iam all excited to be on the road again but.... the "break and anti-lock" lights stay on in the message center i can deal with that for now but the speedo don't work and in these trucks "75 to us is 95 to them" kinda thing so help save my pocket book from a ticket or two
i have done a simple test with my light tester.... according to my wiring diagram the (wight orange) and the (drk blue ) wires run from the tyranny to the speedo and the blue is constant power the wight orange is variable power to the speedo (that's what makes the gauge move) i guess unless iam wrong i have power in the blue but not in the other while moving do those that wire have anything to do with the cluster edit of wires that almost burnt my truck to the ground!!!!!!

Thanks to all that respond!!!
Brice

 

Well,

I can tell you that the rear wheel speed sensor controls the speedometer and the anti-lock brakes. And they commonly go bad.

It's right at the top of the rear diff with a molded plug going into it. One bolt holding it in.

 

it worked the day of the meltdown tho could it of it gone bad like that or is there warning sines

 

I would probably start by checking the fusible links in the main harness under the hood hinge. Might not getting power.

 

oh and this is wrong, it doesn't control the speedometer, the VSS on the back of the trans does. The only thing that controls is the Brakes.

 

huh OK (fusible links).....the speedo has power via the blue wire
but the control wire (wight-orange) dose not have power it travels from back of tranny (as stated) up to the wiring harness on the driver side of firewall then into the cab to the??????? then to the speedo
i cant realy access the cab sid of the harness and its all black from the meltdown

 

Mine made the spedo not register until you were at 15MPH+ when it failed. Put in a new one, and it's fine.

 

This is incorrect information when talking about a 1st gen. The VSS (mounted to the transfer case or trans) runs the speedo on a 1st gen. The speed sensor on the axle only runs the RWAL.

Brice, you are checking the wrong wires down at the speedo. Sounds like you are checking the OD solenoid wires.

Your VSS is supplied with ground, it generates its own signal. Signal wire is orange/white, ground is blue/black.

Make sure the VSS is tight and that the harness is plugged in tightly.

 

Tanks Dave
dose he manual have an od sencer?
and i found those wires how much movent is allowed at the vss?? mine swivls a bit

thanks brice

 

pull the vss out and check if the little square shaft that spins the sensor is not broke off. my speedo wasnt working and i pulled that off and it was broke, i ended up having to fabricate a new one out of a nut driver bit

 

will do thanks
i will post tomarrow about it

 

well i got the brake and anti lock to go off but no speedo??? the vss has the pin still

 

Unbolt the VS from the trans but leave it plugged in. Turn on the truck but don't start it. Spin the vss drive with a drill and watch the speedo. If the wires are all ok thew speedo should register. IIRC it will only work if the VSS is turned the correct way. Don't remember which way that is....