erratic fuel gauge

[teroma25]

So wifey tells me the fuel gauge isn't working right. Everytime I drive the Kon it seems fine. Then one night she gets home and says "Go look at it now" So I go out, fuel gauge is upside down, pointing straight down. Ok, sending unit is fubared I figure. Drop the tank, put new sending unit in, all's good right....no!
After replacing the unit, gauge still pointing down. It seemed to work, just upside down. After a week of scratchin' my head, it's back up top. Yesterday I get in, gauge says 1/2 tank. Drive 30 minutes, make a stop, get back in and start the Kon, gauge says full tank....WTF???? Is the cluster fubared, ground for tank bad, etc.. WTF??? Everything else on the cluster seems fine, except the oil pressure, but I have new sender for that. Need some help with this one!

Anyone have a wiring diagram so I can see how they're wired?
Anyone had a bad cluster do this before?

 

[bkboatnsleds]

Sounds like the stepper motor in the gauge

 

[teroma25]

I didn't even know they had stepper motors in there, will have to look into that.

 

[gfunkfb09]

Yea they do, this is a common problem with our year models. GM knows that they stop functioning and had an extended warranty to get the cluster replaced. When I bought my Yukon it was all working fine until I drove it for a year and the rpm gauge and temp gauge both gave out and pointed funny directions. Nothing they could do about mine because it was well out of the warranty period, stealership charged me $550 for a new cluster installed. So it would be a hell of alot cheaper to fix yourself if you have some technical skills. Its a stepper motor is at it is, and I'm sure someone on here has done it and can help you out.

 

[bkboatnsleds]

Also a guy on ebay who repairs all the motors.. bulbs etc for like 80$ or something.. I think there was a class action suit on this problem

 

[teroma25]

Thanks, I read a bunch of stuff on this last night. Gonna buy a set of'em on ebay and throw them in when they get here. I have no prob with soldering a set in. I can't send my cluster out to anyone because imaginary border fees kill us up here.

 

[jerseyjonny]

i had a problem with mine as well, when i would fill up the needle would bounce all over, i picked up a sending unit rebuild by doorman last week and dropped the tank. the updated unit comes with a new plug which is supposed to fix alot of these problems. i put my tank back up and have filled 3 times since then and its now all good