Speedometer not working on my 94

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98_k1500

strange noises are normal
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Over Christmas, my girlfriend's car motor took a dump (timing belt broke on her kia, destroyed the whole engine). I bought a 94 1/2 ton long bed i knew where was for $400. It had a nv4500 trans, and a blown up 4.3 v6. Had a new pair of heads with it, and i had a low mile 4.3 with a cracked head laying in the shop. Old truck has 362,000 on the clock, and the speedo/odo does not work. Pulled the motor down (been sitting several years) rings were stuck. Cleaned the pistons up, and a gasket set later i had a running truck she can use til she gets something else, then i plan to make some money on it. I plugged to it with a old snap-on OBD1 scanner i have access to and the computer is not seeing a speed signal. The speed sensor looks new, someone has definately had it out and cleaned it up anyway, so i figue throwing parts at it is not going to fix it. Being a 94 with a manual trans, this truck has a DRAC module. It seems to only have 1 plug plugged into it. Images i have found online have a 2nd smaller plug plugged into it. Am i missing some wiring? Or does a 94 only use 1 plug on it? Any help would be greatly appreciated because she really could use a speedo and thats the only thing in the whole truck that don't work.

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The small plug on the left (yellow wire) is not present.

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This one has a red wire in the left plug.
 

someotherguy

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I've never studied the wiring diagram for the DRAC but I believe you'll find the connections are not the issue.

Be sure the VSS is generating a signal. Unplug it, safely support the drive wheels off the ground and have a helper run it up to a low speed, you don't need much. 10 mph or so. See if you can get an AC voltage reading from the VSS. If not, replace it. If yes, then we can go from there...

DRAC's do go bad but it's not very common.

Richard
 

98_k1500

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I have not had the chance to check it, she goes to school 2 hours from here and its been crappy weather here lately so i have not checked for a AC signal from the VSS. I just noticed the DRAC does not have that wire plugged into it when i was wiring up the radio, figured i may have stumbled across the problem. All the radio wiring was all hacked up so i wouldn doubt it if something got accidentally cut out. Doesn't appear the PO was very mechanically/electrically inclined.
 

98_k1500

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Im thinking that yellow wire goes to the cruise. Can't find it on any DRAC wiring diagrams and my truck does not have cruise.
 
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