Help with another VSS no shift problem

[82 dieselburb]

Hello everyone
I am still battling a problem with my vss on my 94 c3500.It started a couple of days ago.Everthing work fine but after I stoped to get some fuel it wouldn't shift out of second ,the brake light was on, and the spedo stopped working.I had code 24 vss low output signal and 72 vss output loss.From reading post on here I figured the output sensor on the transmission was bad.I replaced it and still the same problem .Then doing some more reading I figured out that the vss was not gettting power.The brake fuse which also powers the vss was blown.I replaced the fuse and now have power to the vss and the spedo works.I then cleared the codes and went for a test drive.The truck still will not shift out of second and code 24 low vss output came back.I'm now pulling my hair out tring to get this resolved.What causes low vss output signal?Wiring problem,bad vss,grounding issues,or bad tps??Any input would be helpful.This is my only transportation and I need to work

[JohnC]

I think you need to determine why the fuse blew. whatever caused it could be pulling the voltage down to the VSSB. The code you have sets when the PCM is getting no speed signal. VSSB terminal C8 should be 12 volts and C9 ground.

[82 dieselburb]

thanks I will go check the voltage at he vss with a multimeter.One more question.At the vss besides the 7 pin conector there is a seperate connector that has one red and white wire going to it.I cant find this wire on any of my wiring diagrams.Does anyone know where it goes??Is it supose to have voltage??I thought maybe because it is red it may carry voltage also???I hate electricial problem

[82 dieselburb]

Well I checked the voltage at the C8 pin.I am getting 11.8 volts with the engine off and 12.5 with th engine running.I used the C9 pin as my ground.Is there a way to test the C11 pin for vss output to the PCM to see if it is working properly??Maybe a bad VSS??

[JohnC]

A scanner will tell you what the PCM sees.

[82 dieselburb]

Update .I just drove it down to the store and now everything works fine.I glad it working but hate it because I really didn't fix any thing.I would have rather found a problem and fixed it.Hopefully it keeps on working .Thanks for the help John