Instrument Cluster keeps cycling

My instrument cluster is acting up in a big way. At idle, it's fine. When driving, the entire dash lights up like it's doing the self-test at start up, then goes to normal. Within a few seconds, it does it again and continues cycling this way.

It actually drove fine, and the cruise control even worked.

When I shut it off, the dash lights stayed on a little longer, then shut off and the clock reset itself.

Thanks for any help!

I have the same problem with my 98 Blazer, but it only happens to me occasionally. I cleaned and reseated all my grounds recently and changed the battery after this started happening. I'm suspecting the ignition harness. Hopefully I'll have some time to do take a look at it this weekend. I'll let you know if I find something. What year is your truck?

1997?

2001

Sounds like something to do with the ignition switch.

Hi,
I can't help you...yet. Just this morning I went out to start my 1998 Blazer 4x4 and ran head long into a very similar problem. I jumped in, put in the key and it started right up...no problem. I looked down and ALL Instrument panel lights were on and flickering. I turned off the key and they stayed on and kept fickering on and off. I feared a major short circuit and possible fire so I popped the hood and had a look anticipating needing to disconnect the battery ASAP. I saw nothing unusal. Even checked inside the fuse box. I went back in the truck and all lights were out. I tried to start it and everything is dead...completely.

I leaving work early to start diagnosing this and will fill you in on what I find. Meanwhile, if you stumble on anything please let me know.

My battery and alternator were replaced new about a year ago, but I'll start there anyway to eliminate the obvious. I have all the manuals and will take it a step at a time, but my instincts are telling me ignition switch.

Wish me luck and good luck to you.

Bob

Ignitiotn switch and check the relay.

This sounds like when a relay goes on the fritz. Headlight switch shorting will cause it as well.

Good Morning All, and indeed it is good.

Got home yesterday to diagnose this electrical problem and logically started (at least in my mind) with the battery. Measured voltage at the side terminals was .5 volts. I disconnected the negative terminal and it looked good. When I went to disconnect the positive side, it was hard to turn and white powder came out as it unscrewed. I have never seen corrosion so bad (OK, maybe I have). I ended up replacing the terminal and spend a fair amount of time cleaning the inside threads. BTW, after cleaning, the voltage read 12.8. Blazer started right up and was charging at 14.4 volts.

I feared the worst and for once got lucky. I still find it hard to believe the lights got so squirrely on low voltage.

BlazerLT, thanks, and good luck going forward.

Bob

bob, glad you got things straightened out.

But first, disconnect the battery again and charge it. 12.8volts is too low. It should be about 13.4-13.8volts full charged.

You have a near dead battery, and having the alternator struggling to charge it will lead to alternator failure. Remember, your alternator is for keeping the battery topped up, and is not intended to be a battery charger ever.

Trickle Charge the battery (2A) with an automatic battery charger overnight and get things back up to normal. Also use vasoline on the battery connections to keep them corrosion free.

Great advice and of course you are 100% correct. Being so proud of a quick repair and the saving of hundreds of $$'s; I completely forgot the basics!

Not smart to fix one problem and create another!

Thanks

so true!

It is all gravy from here. ;)