NEED HELP instrument cluster acting up along with ac and radio.

[Silverfang]

I've been having a problem with my 2002lt where the instrument cluster starts acting up ie the pic, the radio stops working, ac compressor turns off, door locks don't work, windows don't work, and if you turn off the car in this stage when it's acting up it will not start unless you let it sit a couple of minutes.
that's the worst it will get, but usually only the speedometer and rpm gauge work, and all the other lights on long with the security light on.
the only additional thing to add is if you tap on the dash over the instrument cluster it usually corrects itself and all the gauges start working again along with the radio and ac.
I'm not sure where to start, new instrument cluster, ignition switch, bcm? the only thing I've done really is cleaned the mass ground to all the systems that are affected are connected. (G201)
If anyone has solved this with their tb I would really appreciate any insights and possible fixes for a broke person.

 

[Mooseman]

Hi and welcome!

It sounds more like an electrical issue rather than the cluster itself since other systems are affected at the same time. I would guess that power to the BCM is being cut off, which would prevent an engine restart as the VATS will prevent the start without the BCM however will not shut it down while driving. My second guess would be that something is bringing down the network, like a misbehaving module, which would also prevent starting but would not stop an already running engine.

Check for codes and your ignition switch outputs. Report back with your findings.

 

[Silverfang]

I don't have a dmm unfortunately, but I bought a new ignition switch and installed it, same problems, unfortunately. Also, I have no codes for my car.

 

[Mooseman]

My second guess would be that something is bringing down the network, like a misbehaving module, which would also prevent starting but would not stop an already running engine.

This would be my next guess. What kind of scanner are you using? It may not give U codes, like U1000, for a network communication issue.

 

[mrrsm]

Perhaps something even 'more primitive' is at play here in the way of having Poor Grounds and Power feeding into and out of the PCM. I'm guessing that if the PCM senses a Low Power Condition... it may shunt "Non- Essentials" OFF ... just to be able to prioritize power and Keep the Engine and Transmission Essentials Working:

(1) Start by visiting THIS Link and downloading the great images posted there in @Realism 's Classic "Grounds" Thread:

Electrical Ground locations

While troubleshooting a bad ground I came across some scans of the service manual regarding electrical ground locations for our platform posted on another site. This includes both short and long wheel base, as well as both 4.2L and 5.3L. Credit goes to Wex...

gmtnation.com

(2) Next, Check the condition of the Battery under a TRUE Load Test over at your Local AutoZone, just to find out if there is a Weak Cell or Two in there or whether or not. It is possible that some of the Lead Plates have decayed into a Lead Sulfate condition, bathed in Strong Sulfuric Acid while suffering from very Irregular Charging Conditions.

(3) If either of the Two Diodes in the A/C Voltage Rectifier located in the back of the Alternator is 'Leaking Voltage' AFTER the Vehicle has been turned off... this condition can cause a Regular Parasitic Drain and run down and diminish Battery Power and even Ruin it over time.

(4) If you've been Seeing your DRL (Daytime Running Lights) *Flickering* from time to time, or you've noticed that the vehicle Stalls after you have turned on your Left Turn Signal... THIS can happen because the Left Head Light, The Left Turn Signal AND the Fuel Pump all Share a Common Ground at G-107 on the Lower Left Side of the Engine Block.

(5) Whenever there are Poor Grounds ANYWHERE in the Electrical System or the Class 2 GMLAN Network, the Power will SEEK to Find Grounds in ways that can FUBAR EVERYTHING... including Module to Module. Communications demanding a reliable 0-7 Volts DC. Remember... Your Class 2 Network AND the SUV Body Grounds Share the SAME Destination Heading Right Back to the Battery Negative Terminal. So Poor Grounds ANYWHERE INCREASES Electrical Resistance which likewise, LOWERS Voltage elsewhere in the Circuitry.

(6) ANY combination of 'ALL of the Above' can diminish the expected 12.5 Volts DC at Start Up and even if the "Faux Voltmeter" reading shows up as 13.5 VDC to 14. VDC on the Dash Gauge... The Alternator will STILL Not be able to properly re-charge a Battery that may NOT be capable of doing so. So... Have the Folks at AutoZone Test Your Alternator, Too.