Oil pressure sending unit or bad dash?

[dna9656]

So, my 06 Avalanche found half the serpentine belt gone, went to AutoZone, it had a 3 year warranty, so got a new belt and another 3 year warranty! The oil pressure is fluctuating, it's full of oil, I installed a Melling (they make good stuff) Hi Volume oil pump 2 years ago when I also replaced the time chain and sprockets (Cloyes) double roller chain, new oil pick up tube, installed 2 collars at the oil pick up tube/oil pump joint, used lock tight, tightened everything IAW the Haynes manual. Cleaned out the oil pan, filed off the casting flash in the oil pan it was surgery clean! When I first got the truck; in 2010 I think, I had read about the screen in the oil pressure sending unit getting clogged so I installed a new sending unit. I can't remember if it was an AC Delco model or not, anyway I have an AC Delco on on order at Amazon ($40.00 cheapest price in the country) the dash cluster is not original, it went to ****** (LEDs burned out, the gauges were operating erratically) so I sent it off and got an overhauled one, so I'm thinking if it's not the sending unit the cluster has gone bad. I'm getting low oil pressure message on the dash and it's chiming too.

Your thoughts?

Edited August 20, 2023 by dna9656
more info

[richard wysong]

Can you check the op with a manual gauge before firing the cannon

[64BAwagon]

I think if the stepper motor was bad on that gauge you wouldnt get the message also. You need to get a reader and see what PSI value its showing in the ECM and then go from there. 

[dna9656]

The gauge is intermittent, the motor isn't clanking like it would were it not getting oil. The pump, chain and sprockets aren't 3 years old, if the crank driven pump wasn't running the engine wouldn't be running smoothly as it always has so I know the op (oil pressure) is ok. It's either the sending unit or the stepper motor for that gauge. I had this issue when I first got the truck, I wend to US SPEEDOmeter.com and got a re-conditioned cluster, they are no longer on line although the website is still up. Nobody answers email or the phone. I am 90% positive it's the stepper motor, seeing as how most of the LEDs are out I think I'll send this unit off for a rebuild.

[64BAwagon]

I still keep a supply of stepper motors and lamps for this era truck even though I dont own one. I also have a few cores that I can scavenge parts from. I do know that there are instances when the plug in the back of the cluster is either loose or the connection on the PC board needs to be reflowed. Its not a real big job to pull the dash and get it apart. At the very least I would pull the bezel and the 9/32 screws and move the gauge cluster out enough to check the plug tightness. Just be sure to turn the ignition off so theres no power to it, they dont like to disconnected and reconnected with the power on.