Hello again everyone,

1997 Blazer 4WD 4dr. Has always had electrical problems, most everything works but there's always been a drain on the battery and I haven't found it yet. It's either more than one thing past the fuse block OR it's inside the engine compartment, because I've been unable to isolate one single cause by pulling fuses and reading current. Not sure if that's related, but I thought it was worth mentioning.

Anyway, late last night I was driving in heavy rain and hit some flowing water on the highway that I didn't see in time, I'm guessing 4-6 inches deep, and it had a lot of corn chaff (the dead stalks and junk after they harvest) floating in it. The car continued running but the warning beeper went off (first time I've ever heard that sound from this car) and gauges went to 0 except speedo stuck at 41, the speed I hit the water at.

There was also a rhythmic noise so I assumed the belt had come off. Pulled into the first available area and popped the hood. Belt was fine. Checked what wires I could for 1am in a thunderstorm, no help. Drove to a better-lit area and listened to the noise, turned out the tailpipe bracket had been knocked out of the rubber hanger by the force of the junk I drove through. I forced that back in, and the car ran OK with no noises, though I knew it was only a matter of time until the battery went kaput.

Got a tow home and been tinkering with it today. As long as there's charge in the battery, everything runs great. I'd immediately think the alternator was shot, but the fact that the gauge cluster is dead has me thinking otherwise. I don't see any problems with any fuses or fusible links. I disconnected the battery terminals for a while and that didn't help. Has anyone had this combination of problems (alternator not charging AND gauges dead BUT vehicle running and other electrical working)?

I also noticed the transmission seemed to shift pretty hard the small amount I drove it, but I haven't tested that any further and it could be my imagination, so take that for what it's worth.

Thanks for any suggestions.

 

Update:

Just checked fuses again. #5 gauges 10A was blown. Maybe I overlooked it the first time, but I definitely checked it once. Replaced, and everything seems fine now. I can't imagine why a blown gauge fuse would prevent the alternator from charging properly, but that seems to be the case. I can't help thinking there's more than meets the eye here (like some messed up wiring somewhere).

I'll update if that ends up not fixing the problem.

 

Not really sure if the gauges and alternator have anything in common on a 97, other than the obvious power wires for idiot light and voltage gauge. I know that the voltage regulators are load dependent, and very sensitive. If any water got into the connector, I could see it creating all kinds of weird problems that the PCM and regulator can't figure out. You said you pulled fuses while checking voltage to see where the draw was. Did you pull the negative off the battery and jump the gap with a DMM? I thought I had a draw on my 01 when I first got it, but it turns out that I had to do the above mentioned draw test with a DMM, and wait 15 minutes after a jumped the gap with my DMM for everything to go into "sleep mode." I know 97's have less electronics in them than 98+, but they also have things unique to that year, such as ignition cylinders that are known for problems. I would also check and see if the underhood light stays on after the hood is closed. Had that plague me for over a year until the light blew.