Hey I have some problems with my 98 chevy blazer 4d 2wd..
I've recently bought my blazer and a few weeks after I got it home I noticed that my battery was dying overnight so i had went and bought a new battery and still was dying checked my alt and it was all good and i pulled my multimeter out and went crazy pulling fuses.

It all summed up to my overhead lights which I don't mind being useless and my radio battery Fuse, I've read around and I've found that the 3 things that are on that Fuse are the instrument cluser, radio, and climate controls. I unplug my radio first and check my draw and it was 0.72 steady and then I went after my climate control computer and was still a 0.72 amp steady i got at my instrument cluster and it's drops to 0.08 which I've heard was a pretty good draw for it being off but it could always be better.

Now to the point do i need to buy a whole new cluster or is there something else that could be making it act up i know there are plenty of modules that interact with the cluster but does anybody have any idea cause I'm running low on cash and can't really afford to spend 200 dollars on a whole new cluster..

When the blazer is off i don't notice anything on or wrong with the cluster it seems normal, currently what im doing is just pulling my RDO BATT Fuse when ever I turn the car off but it's kinda of a task to do constantly. I also have discussed with my dad that it could be the ignition key cylinder grounding out but I'm not exactly sure cause me pulling the cluster fixes the draw like I mentioned lmk what you think and ask questions cause i need this problem fixed.

 

I too have he same issue with my lower mileage 2002 Blazer and have read lots of threads but have not seen anyone exactly say what they did that solved their problem. Someone else mentioned that there may be a wire in the harness to the instrument cluster that is not letting the cluster go to sleep but provides no directions on what to check or what eventually solved the issue. As this not a vehicle that I drive everyday, I too will be pulling fuse 19 until I find a solution online or solve it myself. Hopefully someone that has figured it out will respond before I figure it out. Please update this post if you figure yours out. Thanks

 

I dealt with this for years before I finally installed a 200A marine grade relay installed just upstream of the 175 A mega fuse that feeds the underhood fuse and relay center. It is actuated by a protected toggle switch I installed on the dash and fed from an independent feed from the battery fused with an inline 20A mini ATC. An alternative and much less complex option would be to install a switch (with a guard to ensure it is not accidentally turned off) on the feed to the radio battery fuse so you don't have to pull it everytime. I beleive you would still have keyless entry if you go that route.

I have learned from a company that services and refurbishes GM clusters that silver migration on late 90's and early 2000's GM instrument clusters has been known to cause parasitic draws of enough current to cause the overnight drain which leads to a no crank condition. And these clusters are also infamous for cold solder joints on the smaller terminal pads on the PCB. Specifically both ends of the small, short, stranded conductors from the PRND321 and ODOMETER displays to the main cluster board, and more specifically, pin 1 on the display boards which is nestled real tight to corner of the display board. GM at some point added a thin layer of silicone based potting compound on the display boards I assume to try to mitigate the soldered connections popping loose, but on mine anyway this mitigation measure proved to be unsuccessful. But a logical speculation could be made that an intermittant ground connection to the ODOMETER display would cause the BCM to "wake up" every time the ground connection is re-established, causing the draw you are seeing. Once the cluster is nice and warmed up, one could assume the thermal expansion of the materials is sufficient to temporarily "fix" a suspect cold solder joint, so nothing appears out of the norm with the cluster....until the truck is parked for the evening, every cools down a bit, contracting, and while doing so, initiating many "wake ups" as the night progresses. Check all of the solder joints with a magnefying glass, and re-solder any suspect joints especially the ones I described earlier on the displays. Good luck! Like I said, it was 2.5 years before I snapped and just started isolating my battery from the entire electrical sytem when the truck was going to sit for more than 4-6 hours.......

Best Regards,

Ryan

 

Thank you Ryan for the very detailed work around that you have created.

I will retain this info and at some point tackle this issue. It’s frustrating but its a vehicle thats only driven every few weeks and sits on a trickle charger for now.

Allen