2004 Tahoe Electrical Gremlin

[TexasWhiskey]

History - 1 year ago had very dim cluster panel and it started displaying illegible characters. More Spanish than English but I am in Houston and my Spanish speaking friend told me it was gibberish.

I went to junk yard and removed a 2003 Suburban panel and installed and it worked great for about 10 months.

I was getting a engine light on occasion and it was occasional P300 misfire (which I fixed with coil/plug). I plugged in my code reader when engine was running (NOTING because instructions are to use with ignition on but not cranked). Suddenly I got numerous lights on cluster including alarm system, traction control, cel, etc. but all were not real issues. Power it off and it cleared all except traction control stayed on but eventually would clear on its own. So for a couple months this would randomly happen. Then one day (summer) I noticed the rear air would not blow. Thought it was fuze so swapped some 10 Amp fuses around in a parking lot (did not have meter or fuses) and it started working again. Since then these scenarios have happened several times but fuses are not blowing. Sometimes they clear while driving, sometimes after power cycle.

Yesterday I started realizing every time I try to turn the rear hvac fan on (via over head controls) the fan does not work but it triggers the cluster panel Christmas show that calms down but usually leaves the traction control light on.. but again it can clear while driving or after a power cycle. Rear fan works sometimes and other times not.

My limited skill set tells me its obvious a lose wire that is related to all of these items (rear fan, cluster panel, traction control light, etc) but no idea.

I have shipped my old cluster off for repair and may go buy another one from chevy to be confident.

QUESTIONS:

Anyone experienced this and do you know likely problem?

Anybody have the electrical schematics and know how to read them for a common problem?

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

I cannot personally assist you with your issue, but other members of this Forum much more knowledgeable than me in this area will chime in.

I will say, however, that these trucks are very sensitive to low voltages. I'm not sure that all of the issues that you are experiencing have the same root cause, but you should start by eliminating and potential battery and ground issues. Take the battery out of the truck and have it bench load tested at a local auto parts or battery shop with a bench load tester. Check both battery cables for any signs of corrosion, but look carefully, as these cables tend to rot from the inside out.

Next, check all grounds in the engine bay and ensure that they are clean and tight. Also check for a ground connection on the truck's frame underneath around just below the driver's feet.

You can find electrical schematics for your truck at this web site: www.charm.li

As I indicated previously, other folks on this Forum will chime in as well.

 

[Fless]

In addition to what @Joseph Garcia recommended, Google "voltage drop test" and confirm that the connections from the battery are good to the body; mostly that will be the negative/ground connection.

The ground under the driver's foot is on the body mount that is attached to the left frame rail, approximately underneath the driver's door hinge area. Right behind the LF tire -- what a great place to put critical grounds, GM.

 

[justirv]

What @Joseph Garcia and @Fless said, and if you get ambitious, check out threads on the Big 3 Grounding upgrade. Any improvement to current return path helps all systems.