Any car guys here? Need help.

[alexwakelin]

I drive a 2000 S10 4x4 Blazer. Today my odometer went out, the strange thing is that the trip odometer still works. I'm usually pretty good with car/mechanical stuff but this one has me stumped. My Blazer has a digital odometer, and the trip odometer button toggles between the two. Anyone have a clue what could be the problem?

 

[Davemcc]

I will speculate that the odometer and the trip odometers run off of different electrical circuits. The main odometer should have an electrical connection to the PCM, which logs mileage, while the trip odometer does not need that connection to the PCM. There may be a loose connection or a short in the wiring from the odometer motor to the PCM or from the PCM to the dash display. Just speculation, mind you. Hopefully, it's not a PCM failure.

 

[alexwakelin]

I forgot to mention, the odometer still displays 80997, so while it did not fail completely, it is "stuck".

 

[Sheep]

From my experience with cluster swaps, the mileage is stored in the cluster itself. I don't know if this is the same for domestic vehicles, but you might be looking at a new cluster worst case scenario.

SheepStar

 

[Davemcc]

Again, just speculation, it may be that there is a short or disconnected wire between the odometer motor and the PCM and the PCM is simply displaying the last recorded input, as if the truck hasn't moved since there is no electronic input.

Do you have a scanner to check if it's throwing a code? Sometimes buying the scanner from a parts store is cheaper than paying for a single scan at a repair shop.

 

[alexwakelin]

Any idea where the pcm is located on that vehicle?

 

[Davemcc]

Little bit more here, a couple of possibilities:

http://townhall.edmunds.com/direct/view/.f0dda29/120

 

[Sheep]

Any idea where the pcm is located on that vehicle?

It's usually right behind the gauges. It's all one assembly.

SheepStar

 

[alexwakelin]

It's usually right behind the gauges. It's all one assembly.

SheepStar

I was afraid of that. The dash is a PITA to remove, I vowed I would never do it again after I installed the stereo 2 years ago. I should have some time Sunday to tear into it if it is warm outside.

 

[Davemcc]

I believe the PCM on most GM vehicles, this one included, is under the hood on the passenger side firewall. It should be the large connector with a lot of wires going into it.

 

[alexwakelin]

I believe the PCM on most GM vehicles, this one included, is under the hood on the passenger side firewall. It should be the large connector with a lot of wires going into it.

I'll check there before opening up the dash. So first step should be to locate PCM and trace the wires back? Check for any obvious shorts?

 

[alexwakelin]

I already got my fill of monkeying with the car today. After work I stopped at Discount Tire and got a rotation/balance. Picked up oil and a filter on the way home. I moved my sub amp to a better location and installed a new ground cable for it. After cleaning out and vacuuming the entire interior I changed the oil. It was then that I discovered my odometer wasn't working. I wonder if the tire goons are to blame? Think they could have knocked something loose?

 

[Davemcc]

Best idea yet. Looks like a well educated bunch on that particular vehicle.

http://blazerforum.com/forum/index.php

 

[alexwakelin]

Best idea yet. Looks like a well educated bunch on that particular vehicle.

http://blazerforum.com/forum/index.php

I posted there too, but I think they're all sleeping right now

 

[unreal.freak]

My PCM is behind the glove box, inside passengers ide, on the firewall, I have a 1989 silverado. May be different on the blazer though.

 

[jonnythan]

Looking at the pictures in the service manual, the PCM appears to be located right in the engine compartment...

Should be a box with four electrical connectors on the back. Looks to be right above the A/C receiver/drier.

Anyway, the troubleshooting chart says that if the speedometer works properly, the next step is to replace the instrument cluster itself.