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just wondering if the speedo/odometer is mechanical or electrical, there is wiring coming from the t-case, I just found some questionable wiring that is unplugged under the dash, just cant find where it plugs into. dont want to tear into the dash if I dont have to. thanks

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Electrical. signal comes from the rear-end. VSS - vehicle speed sensor.

 

the wires off the t case turns the light on in the dash for 4 hi or 4 low. if it's a manual transmission there is a wire just to turn on the reverse lights. as far as wires under the dash. my 96 had a few of those. i did'nt know where they went either. but everything worked just fine.

 

Hell yea!! thanks guys! but does the VSS run the odometer too??

 

yes.

 

call me blind but I can not find the VSS to save my life, I see the plug in coming off the harness but i cannot find the connection on the axle, it is a dana 70u & its hard as hell to find info about. i know the 10.25 sterling's vss is right on top. were obs fords ever built with dana 70u's or did i get a bastard?? any help is appriciated!

 

still cant find the VSS, it's a '96 250 with a dana 70 rear. any help is apriciated, thanks.

 

Are you saying the VSS harness is NOT connected to anything at the rear diff? If that's the case, I'm stumped.

The VSS sends a signal to the PSOM that the PCM uses. If it doesn't see this signal, the PCM usually puts the vehicle into "limp" mode and all kinds of things start happening. Auto tranny shifts HARD! OD light starts blinking. PCM sets a trouble code. Any of this happening with your rig?

If you have a handshaker, the above bad stuff doesn't apply, but the PCM still needs the signal from the VSS.

Maybe some pictures of the rear diff will help. That connection doesn't have a lot of slack in it. You should be able to stretch it to the diff to get an idea where it should connect.

 

yea, I cannot find any connection, but that is exatly where this part of the harness leads to. the sensor is all banged up and I cannot find where it plugs in at. one guy said either off the rear end (which I know the 10 1/4 does), in the tranny or tcase, or even the backing plate for the brake drum. I have a ZF5 tranny so i dont think its driving different but I cant tell bcuz I bought it this way and the ABS light has been on since I bought the truck in october. I will try and post some pictures. also i've been told that the ABS and VSS are the same?

 

No. The VSS and RABS are different. There will be some that want to argue this point but ask for one or the other at the Ford parts counter and you'll get two different parts that belong in two different systems at two different locations on the truck.

The VSS should be on top of the rear diff, most likely under the sway bar. It is a two-wire connector and the sensor itself is held in place by one bolt. The entire swap process shouldn't take more than two minutes and that includes a coffee break. The VSS may assist the PCM in determining wheel-slippage / spin to activate the RABS. The VSS does what it's name implies, it senses the speed of the vehicle and sends this information to the PSOM, where you see the result on the instrument cluster. This information is then sent to and used by the PCM.

The RABS is located on the driver-side frame rail. If your ABS light has been on since October, you have a separate issue to deal with. Sometimes, bleeding the brakes and the RABS, in the proper order, will take care of the problem. IIRC, the order is:
1. Right rear
2. Left rear
3. RABS
4. Right front
5. Left front

You need to check for codes ASAP. The ABS light on is NOT something to dismiss. It is a safety issue that needs to be corrected; the sooner the better.