My problem is kinda odd, in my opinion. My speedometer, odometer, and cruise control will sometimes work, and sometimes not work. The odometer appears to work when the speedometer works. The cruise control, however, may or may not work when the speedometer IS working and it may or may not work if the speedometer is NOT working. If the speedometer decides to start working at highway speeds, the radio will get louder!
The transmission seems to be working fine, although it will sometimes shift kinda hard into second gear after it warms up (but not all the time). The airbag warning light comes and goes, too.
The Check Engine light is on and my scan tool says that I have a bad O2 sensor and shows the vehicle speed at the time it coded. I erased the error code and when it came back it still showed the vehicle speed when it occurred.
I took the cluster out and checked it for cold solder joints and cracks and found nothing. I then ordered a replacement cluster on eBay that has 63,000 miles on it and it does the exact same thing my original one does.
Anyone got any ideas on this? Is it possible that my ECU is bad? Could the VSS be faulty even though the transmission seems to be shifting ok?

 

Well the stock head unit increases volume as you speed up so that part makes sense. The rest is more stuff I'm unfamiliar with.

 

Yea, actually, I know that, but I put it in there as it's something that happens when the speedo starts working.

Also, I forgot to mention that I tried running a jumper wire from the ECU to the speedo (dark green wire), but it made no difference either.

BTW: For what it's worth, we have a 2010 Ford Fusion that has that feature on the radio and I HATE it. Luckily, my wife drives it most of the time.

 

What was the specific code that the scantool returned?

Replacing the cluster is like fixing a symptom without addressing the cause. All of the systems that you are having difficulty with reference the VSS signal as does the cluster. The cluster is just an information dissemination device and does not control anything else directly.

 

I had to go out and re-scan the ECU (I couldn't remember the exact code) and actually came up with 3 codes, one of which is not very good.

Here are the codes:
P0446 Evaporative Emission System Vent Control Circuit [generic]
P0147 02 Heater Circuit (Bank 1, Sensor 3) [generic]
P1870 Trans Component Slipping [GM] <-- Not good!
All of these show other data that is the same between all of them:
1621 RPM, Speed 34 MPH, Temp 177, Throttle Position 12.9%, etc.

I have erased the DTC's and will re-scan the ECU again as soon as it codes to see if it remains the same. However, I don't believe that any of these are related to my speedometer issue. But the way these things are built, I could be wrong.

 

Well, it coded again yesterday during a 200 mile trip. This time, the only DTC that showed it's ugly head was the dreaded 'P1870 Trans Component Slipping'. Again, I don't see that this would have anything to do with the speedometer issue or even the VSS because the VSS is located toward the tail-shaft of the transfer case, not inside the transmission.
I may go ahead and install a new VSS, I just don't want to waste the money on one if that's not the problem. I was just hoping that perhaps someone else had the same problem and could tell me what they did to fix it.

 

Well, I went ahead and got a new VSS this morning and got it installed. Guess what? It didn't fix my problem. $86 down the drain.
I have to work this weekend, but on my next couple days off I'm going to see if I can trace down the ground wires to the speedo. Does anyone know what the "splice packs" look like and where they are usually located?

 

Your shotgun approach to trouble shooting is only going to frustrate you and waste your money. DO NOT continue to replace things needlessly without troubleshooting! TEST!! Test methods for the VSS sensor have been posted numerous times in the past. Your approach will also make many people not even bother trying to help you since you seem so hell bent on taking the quickest route to an answer regardless of whether it was the direction you needed to go in or not...

Quite frankly, your incessant need to erase codes is why you don't have a clue what is going on...by resetting the computer every time you want to look for codes, you aren't allowing the computer to go through all of its checks and see all of the errors. Some error codes have to accumulate multiple errors before they will set a code or trigger the light. By resetting the PCM every time you read the codes, you are shooting yourself in the foot making it seem as though throwing parts at it is your only recourse...

Can your scan tool do anything other than read/display/erase codes? Display sensor data while you drive down the road perhaps?

 

If you're going to be a smart-*** about it, then I don't need your help and you can just delete this post AND my account. I didn't come here to be chastised by you or anyone else here. I came here for a little help.
YOU are the one that said everything seems to point to the VSS. You could have added that I should test it and perhaps point me to some posts that told me how but you didn't. You also seem to be "Hell-bent" on focusing on my DTC codes instead of my speedo problem. My bad for mentioning it I guess. I also asked some specific questions that you never bothered to answer.
I have a very limited time to work on this Chevy piece of crap and also can't afford to take it to a dealer just to pay them hundreds of dollars and it still not be fixed (been there, done that), therefore, the $86 I wasted was actually cheaper than my local dealer or other repair shop. "Throwing parts at it" is all they ever do and charge exorbitant labor fees on top of it. The only reason I have this Blazer POS is because it was given to me. Otherwise, I wouldn't own one.
BTW: I don't erase codes every time I read them. It had been over 2 months since I erased the codes the first time and there were no pending codes when I did it this time.

 

I am one of the only people that was actually trying to help you, but you would rather read into a post in such a way that it is only negative; likely out of the frustration that you have allowed an inanimate object to inflict on you...

So this is my fault for not pointing out that you should test things before replacing them. Sorry... I thought that was what people call common sense, but that seems to have died a long time ago. I never once said to replace the VSS. An industrious person would have taken the direction given and searched for information to that end (perhaps information provided in the past by said person - hint, hint). As I am quite busy, I simply cannot do the leg work for you. I'm sure you can understand that being that you said you were very busy yourself. So again, sorry I couldn't spoon feed you; such is life.

And there was no 'smart-***'ery involved from my end at all, yours on the other hand... I mean come on, your remark about the VSS not fixing anything was a dig at me, like somehow it was my fault. Again, you are letting your frustrations with your vehicle flow into how you interact with everyone else...

If you still want help, here are some questions you forgot to answer in your rant:
To that I'll add a few more:
Have you tested the VSS wiring?
Do you have access to wiring diagrams?
Do you have access to a multimeter capable of doing continuity testing & resistance testing?

Or, just get rid of it and save yourself the frustration.