So I just picked up this 2001 Chevrolet Blazer 4.3 V6 4x4. Thing runs flawlessly, but it's having some major problems with the cluster.

I've heard cluster problems are famous on these, but it's really stumping me, and I'm good with electrical. What happens is, when I start it, every single light illuminates, the only gauge that works is the speedo, the odometer doesn't work. And what gets me even more, is when I turn the truck off, they still stay illuminated, even when I remove the CLSTR fuse!!

What can I do about this? Any help would be appreciated.

PS: I've also got another question for you, it has keyless entry, but they said the battery was bad, I replaced the key fob battery, but it still doesn't work?

 

To accurately diagnose the instrument cluster, you'll need a bi-directional scan tool that is capable of accessing the cluster.


For the keyless entry: You first need to find out if the vehicle was equipped with it from the factory. Inside the glove box door there is a black & white sticker. It has several 3 character codes. If you have "AU0" listed, the vehicle is equipped with it, and we can help you diagnose the problem.

 

It has keyless entry, as for the scan tool, what if I can't get one?

 

This post might help you on the remote. It might just need programmed.

https://blazerforum.com/forum/2nd-ge...ramming-86978/

 

I was also able to get into programming mode successfully, more than once. But when I hold the buttons on the key fob, it never syncs, could it just be a bad fob?

This is my dash cluster, while the Blazer is running, for those of you who may know how to fix it:

 

Scan tools necessary for diagnosis on the cluster are available used, through Ebay. They usually start in the $1500 to $2000 range.


I have seen that exact problem with the lights several times, once on one of my own vehicles. You might want to try this: Remove the cluster and disassemble it. On the back side of the printed circuit board, at the very top, there is a 24 pin electrical connector, (you need to unplug it to remove the cluster). Using a low wattage soldering pencil, (30 to 40 watts) and rosin core lead/tin or silver solder only, reflow each solder joint on the printed circuit board for the connector. Probably will require the use of a magnifying glass to actually see what you're doing Definitely worth a try, if it does not cure the problem, there may be a problem with the logic module on the circuit board requiring a new, or rebuilt cluster.


As for the keyless entry:


In the underhood panel fuse panel, using a test light or DVOM, test both terminals of fuses #7, (3 amp fuse), & TR C, (10 amp fuse). Do not remove the fuses while testing. Both fuses must show battery voltage at all times.

In the instrument panel fuse panel, check fuse #14, (15 amp) fuse. This should also show battery voltage at all times. Post your results.

 

There is a "bulb test" module that is supposed to illuminate all the bulbs upon start-up and then switches off; looks like yours is not switching off.

I think the module is within the Body Control Module (BCM) but not 100%. I am pretty sure that the odometer reading is stored in the BCM and since yours is not working, I am thinking the BCM is defective.

Definetly try what Captain suggested as I have fixed many a problem on various vehicles by re-flowing solder connections. In fact doing this with on the BCM may fix it as well, never had to do a Blazer BCM....you have nothing to lose by trying.

Another suggestion would be to get a BCM out of a salvage yard or borrow one from another Blazer. I would offer you to bring it over, but just a tad bit too far....

Let us know what you find out.

 

Going to try a different BCM like you suggested this weekend.

I took a little video of how the cluster reacts while running, and while starting. Sorry about the music, my other half was jamming out haha.

https://drive.google.com/open?id=0Bx...jZmQjJzM0V2RXM

It also decided to work semi-normally for the first time since I've owned it. The lights all went out, and the tachometer and temp gauges worked.

https://drive.google.com/open?id=0Bx...lhWdS03bEtPMEU

 

The BCM does NOT control the cluster, mileage is stored in the logic module in the cluster. The IPC, (instrument panel cluster), BCM, EBCM, SRS, and PCM are all networked together. When a module needs information that it does not collect, it requests it through class II serial data from the module that has it. If you install another BCM, it will need to be programmed to your VIN. Try my suggestion in post #6. If that doesn't fix it, find someone with a capable scan tool to diagnose it for you.

 

Will do, didn't notice any cold solder points when I had it removed, but I'll try using a magnifier tomorrow.