Likely spot to start tracking under dash wiring problem.

[Vincent L Gilbert]

Vehicle is 1999 Yukon Denali, it was a rescue to start with and here on the Oregon Coast..corrosion could eat a hole in a Battleship in a few months. So a while back, the 4WD controller started acting wonky. Pressing 2WD high would cause it to jump to 4WD high, etc, but eventually you could get it into the mode you wanted. Then it went dark...stuck in 4WD low of course. Since it was a tow vehicle not a daily driver, I didnt mess with it...and when I went back in, turned on the radio..nothing, hit the air...and could tell it popped a fuse and the entire right side of the dash blacked out. So I figure the original problem is corrosion related and under the dash. Hoping there is a harness/connector that someone might be able to identify from the symptoms that would give me a place to start looking.

Thanks in advance

 

[OR VietVet]

Welcome to the forum from Oregon as well.

I am familiar with the corrosion problems from the salt air at the coast. I have popped hoods and seen the signs of it and knew the vehicle spent time on the coast. First thing to check is always fuses and any wiring that flows to the doors thru the umbilical cord in the door jam. Check all wiring under the hood and under carriage. But one of the places that needs inspected is all the grounds. There are numerous ones and all important.

 

[Vincent L Gilbert]

Thank you sir! Have bezel popped and kick plate off, Multimeter in hand. Beginning the search . Gawd I hate wiring with a purple passion.

 

[OR VietVet]

You are going to find that it is best, if you have the time, to find the ground, open it up and inspect and address as needed and reassemble. Don't assume. Open and look.

 

[Vincent L Gilbert]

Sound advice. Going slow in an attempt to not go from bad to worse. Ive already destroyed one switch back on a door panel atempting to get the harness off. While I appreciate the engineering on these, Im starting to wonder if there isnt some secret squirrel OEM tool im lacking when attempting to remove. These are tough by normal standards. Worse under the dash...its tight.

 

[YukonGTmaster]

Vehicle is 1999 Yukon Denali, it was a rescue to start with and here on the Oregon Coast..corrosion could eat a hole in a Battleship in a few months. So a while back, the 4WD controller started acting wonky. Pressing 2WD high would cause it to jump to 4WD high, etc, but eventually you could get it into the mode you wanted. Then it went dark...stuck in 4WD low of course. Since it was a tow vehicle not a daily driver, I didnt mess with it...and when I went back in, turned on the radio..nothing, hit the air...and could tell it popped a fuse and the entire right side of the dash blacked out. So I figure the original problem is corrosion related and under the dash. Hoping there is a harness/connector that someone might be able to identify from the symptoms that would give me a place to start looking.

Thanks in advance

I would start by climbing under the truck, and pull the connector off the actuator, that goes into the front differential. My connector was filled with water, and shorted out the actuator. I replaced the actuator, cleaned the connector, and filled the backshell with DC-4 before plugging it back in. Definitely needed some replacement fuses too.

 

[Vincent L Gilbert]

Vehicle is 1999 Yukon Denali, it was a rescue to start with and here on the Oregon Coast..corrosion could eat a hole in a Battleship in a few months. So a while back, the 4WD controller started acting wonky. Pressing 2WD high would cause it to jump to 4WD high, etc, but eventually you could get it into the mode you wanted. Then it went dark...stuck in 4WD low of course. Since it was a tow vehicle not a daily driver, I didnt mess with it...and when I went back in, turned on the radio..nothing, hit the air...and could tell it popped a fuse and the entire right side of the dash blacked out. So I figure the original problem is corrosion related and under the dash. Hoping there is a harness/connector that someone might be able to identify from the symptoms that would give me a place to start looking.

Thanks in advance

Follow up. Once in , the wiring was in remarkably good shape. Traced problem(s) sketchy ground at the battery. (repaired) , heater blower was frozen due to corrosion which caused the fuse pop. And after looking at the 4WD switch operation, and reviewing other people with similar and in some cases identical issues, Id say the the original problem was localized at the switch itself.

Thanks again for te input

 

[east302]

On that rusty blower, the passenger side screw holes for the plastic cowl at the windshield can leak water into the blower intake. At its worst, it’ll flood the blower housing and spill onto the floor.

If you pull the blower and look up into the air intake with a mirror, you’ll see one screw poking through the metal. There might be another but I forget.

A healthy goobering of silicone or whatever you have laying around usually seals it up.