04 Yukon crank but no start, no radio, no power windows/locks

[Fless]

If you have water migration into the engine computer connectors again, you may want to inspect and replace the gaskets on the connectors. Pull those connectors off and dry them out, maybe use some DeOxit on them.

 

[Mortimer452]

I pulled the ECU, there was a little water in the connectors. We have had ZERO rain in a month here and I'm certain nothing splashed in there since last time it happened, so I don't think it was thoroughly dried from before. I removed its cover and let it lay on my workbench with a fan blowing on it overnight. Put 'er back in the next morning and it works fine, however the pins on the connectors are *really* badly corroded, I tried to *gently* clean them off but some of them are really, really brittle. It's good for now but I think I will order a new ECU anyways just to have it on hand if it happens again. The corroded pins are so brittle I bet I would break a couple next time I had to remove the plugs.

 

[rockola1971]

I pulled the ECU, there was a little water in the connectors. We have had ZERO rain in a month here and I'm certain nothing splashed in there since last time it happened, so I don't think it was thoroughly dried from before. I removed its cover and let it lay on my workbench with a fan blowing on it overnight. Put 'er back in the next morning and it works fine, however the pins on the connectors are *really* badly corroded, I tried to *gently* clean them off but some of them are really, really brittle. It's good for now but I think I will order a new ECU anyways just to have it on hand if it happens again. The corroded pins are so brittle I bet I would break a couple next time I had to remove the plugs.

You can order truck side wiring plugs and replacement pins and recrimp them on the existing wires after they are cut back and stripped. Fun job.

 

[foster22218]

hopefully someone on here will read and reply I’m having the same issue but I noticed the on my instrument panel display it will put out weird letter for example lastnight I saw an meme Er er not sure what to do

 

[MassHoe04]

hopefully someone on here will read and reply I’m having the same issue but I noticed the on my instrument panel display it will put out weird letter for example lastnight I saw an meme Er er not sure what to do

Easiest items to check on first would be ground connections. The wires on the body mount below the front driver's side door are key for grounding out the body control module and a lot of the electronics in the truck. Start there. Remove, clean everything and make sure connections are solid. Grounds in the engine bay are also critical. Check, clean, make sure they are solid there too.

Look for any obvious damage/corrosion in the power distribution box. Mouse droppings and urine can do a lot to corrode connections in the box, if they get in there to set up house.

None of this casts any money and just a little time. Start there and let folks know what you find.