Anyone seen this electrical problem? 2003 Tahoe

[mountie]

My Brother just retired from a civilian job at San Diego-Navy / North Island.... Machinist....

When a chopper made a "hard landing", or a part fails on a Tomcat, he would get a call and start making new 'better' parts. ( He made a lot of parts)

 

[pwol1962]

Got her figured out. Luckily I have 2 2003 Tahoes and I robbed the alternator off the wife's Tahoe (Its waiting for me to change out the transfer case). Im wandering around my house wondering where on earth my voltmeter is and it dawns on me...."Hey Stupid, You have a Tech 2 and it will show alternator voltage". Well it sure did. With engine running the voltage was 11.6V. So I swapped out the alternator and all is good now. Putting out 13.9v and cluster, Auto climate display and mirror temp/compass all work fine now. Apparently the Cluster is Very sensitive to voltage under 12v. It was all completely dead. Gauges, message center and all indicator lights.

I experienced the exact issue with my 97,000 mile 2003 Suburban last fall. After checking the battery and alternator output I discovered that the alternator output was not getting to the battery. I disconnected and cleaned every electrical connection from the alternator positive post, thru the junction block to the positive battery cable. All "looked good" but had oxidized. This resolved the problem. I initially thought that it was a defective alternator.

 

[LEDFoot]

... Apparently the Cluster is Very sensitive to voltage under 12v. It was all completely dead. Gauges, message center and all indicator lights.

I believe "non essential" items shut down first as to keep the engine running for as long as possible.

 

[mountie]

Limp Mode.........

SCOTTY !!!! OVER-RIDE !! OVER-RIDE !!!

 

[rockola1971]

Limp Mode.........

SCOTTY !!!! OVER-RIDE !! OVER-RIDE !!!

View attachment 240453

Thats exactly what limp mode is not.

 

[rockola1971]

I believe "non essential" items shut down first as to keep the engine running for as long as possible.

The cluster didnt shutdown and wasnt shut down. It just didnt have enough power to feed its own internal regulated power supply since there are mutiple voltages that are used within the cluster. So it wasnt able to operate.