Keep hitting Dead end 05 Kon Issues

[SHWELL]

Hey guys. Sorry if I am annoying.. But I am at my end dealing with this Truck.. 2005 Yukon 5.3l

Got the Truck a month ago (Literally) and a week after taking ownership, I got the CEL for the Knock Sensor.. Fast Forward 2 weeks and my Cooling Fans run continuously whe the vehicle is off. This kiled the battery. A few days later the vehicle starts running ROUGH with little to no power.. When the AC or Heat is on, the truck tries to Stall at low RPM's

-CEL for the Knock Sensor..

-Cooling Fans run continuously whe the vehicle is off.

-This killed the battery.

-Running ROUGH with little to no power..

-When the AC or Heat is on, the truck tries to Stall at low RPM's

-Upper Coolant Hose Leak


This is all that has been done this week:

Changed both Knock Sensors (Factory)
Replaced all Plugs (Stock Replacements)
Replaced Temp Sensor (Factory)
Replaced Cooling system Relays (All)
New Battery (AC Delco)
Upper Cooling Hose
Cooling system Flush and refill


Most recent Codes are p0480 (Fan code) and p0300 (Misfire).. I plan to replace all the plug wires today. Since all these changes the truck is running stronger than it has since aquiring. I am really stuck with this Fan issue though. I have not found anything online or this site that has an answer to this issue. The specific problem has a threadon it, but no fix listed.

Here is a pic of the old Temp sensor and one of the bad knock Sensors:




Any help would be greatly appreciated. My next step is dealing with the dealer (Which I would like to avoid).. Electrical issues have never been an inexpensive endeavor when the dealer is involved.

The Efans running constantly is my #1 concern right now.

 

[CEN2MENTAL95]

How many miles ? I recently had a cel at 126k . Come to find out it was a misfire. Replaced #8 fuel injector and coil misfire gone!

 

[SHWELL]

99821

I am currently awaiting a call from the dealer.. I think the misfire situation is resolved with the new plugs and wires.. The Fan code is the only one left..

 

[yates ™]

Did you replace the relay for the fans?

 

[SHWELL]

yes. as listed.

 

[SHWELL]

Temp Sensor Replacement, and complete cooling system flush and fill seemed to fix the EFan issue..

The other problems (Lack of power) were fixed with Coil Replacements, new plugs, New wires..


But based on how some things looked, looks like the Head will be removed for a good inspection.. Hate to do it, but the work is free so I cannot complain and would rather be safe than sorry.