I have a '99 NBS Silverado 2500 4x4. The speedometer and odometer do not work but using my scan tool and live data I can verify that the ECM is getting a signal from the VSS. It reads a speed on the scan tool but not anywhere else. The transmission shifts fine. Cruise also won't set, it powers up and light goes on if I hold the set button but it won't stay set.
I do have an ABS and Brake light on. I know the ABS module is jacked up and I plan on sending it in for repair. Could that be the issue? I don't have an ABS sensor code just for the module. Is there anything else to be looking for? How can I verify if the speedometer gauge motor is working?

 

Looking on Alldata at the wiring diagram for the VSS portion of the truck, it appears that the signal goes to the PCM with an output to the instrument cluster and one to the electronic brake control module. What I'm curious about is if the EBCM isn't working if the PCM shuts off the signal to the cluster? I will run a continuity check and see if I'm getting signal to the cluster to rule out a broken wire from the PCM tonight. If I get signal to the cluster my next question is how to check the air-core stepper motor is functioning?

 

Bad cluster? They are notorious for going out on 99-02 years. I've bben through 3 of them. And I also have the abs and brake light on. Ebcm performance error. It can be intermittent. But does not affect my cluster. Try the ground wire clean up tsb. Might get rid of your lights.

-Kyle

 

The ebcm should not affect the odometer/speedometer, are you seeing vss signal in the ebcm? If all the other guages work, i would suspect either broken wire, something screwy with pcm or connector, or a bad cluster.....

Knock on wood i have yet to have an issue with my 99 thag wasnt operator error... My fiel guage is way off since i installed my guage face... Last time i filled up i think it resetitself though, as it was reading slightky over full, as is the norm....

 

I have never seen the Ebcm mess wit the speedo or odemeter. My bet is the guage cluster. They can be had for cheap. Car-part.Com. that'll save you money in the Ebcm. Just forget about the lights on your dash. Typical chevy problem.

 

Cheapest place i have found for reman ebcms is napa... They carry the dorman remans and last time i had to get one was less than $200 and they had it on the shelf!!! But i doubt very seriously the ebcm is affecting the speedo/odo.. Not aaying its not a cluster, but needs to rule out wiring as well!!

As far as ebcm causing brake and abs lights to come on, if you are patient and good with a soldering iron, there is a fix for the burnt solder joints.... The ebcm has to be opened up and there are two or three solder joints that crack... I am about to pull mine and see if i cant fix it, but i already have another abs unit waiting if either i screw the pooch or it doesnt fix it!!!

 

I agree with you. But if you don't mind the lights on I wouldn't worry about it. And there are several you tube bids in how to fix them. But as stated before it would hurt to do the service bulletin for the ground wire. Might or might not help. Didn't with mine. I just deal with the lights. But IMHO I would swap clusters just to check. Maybe you have a buddy that you can swap with. And like I said before. I have been through 3 of them. Best of luck. Maybe check all the wiring. But that is a pita. Worst case pull the bulbs if it bothers you. Lol

-Kyle

 

Pm me bud if you need to chat about it. I've been dealing with mine for awhile. I'm glad to talk to you about it.

-Kyle.

 

Gotta update this now. In troubleshooting and tracing wires I found a mouse nest........under the black plastic cover for the underhood fuse panel. The ONLY wire that got chewed was.......wait for it........the speedometer. A little splicing action brought everything back to life, speedometer, cruise control and even the dang auto door lock!
But on another note, I'm kinda wondering if I have a funky oil pressure gauge or sender......the needle bounces. Not a lot but I don't see the pump causing it to do that. Sender is cheap enough I may try that first before replacing the oil pressure air core motor. Plus the temp gauge is off by about 15 degrees (according to my scan tool). I assume that has to be the air-core motor because the PCM and gauge get the signal from the same place?
I was a little hesitant to try and fix the ECBM but I am going to find it on Youtube and try and save some cash. I work with soldering irons and small connectors all day, I'm fairly certain I can tackle that little project.

 

Haulin, i just read your go fund me page... I too am a fellow member of the zipper club, glad youre doing ok... I had a triple bypass a little over 2 years ago now... And it has been a struggle to say the least, still dealing with repercussions from surgery both physically and financially....

As far as the ebcm fix it looks fairly straight forward....