**Solved** 2005 z71, E Fan stays on when vehicle is off, doesnt shut off.

[TotesMcGoats]

Hi there, 2005 Tahoe, z71. I noticed in the morning my cooling fan was running. Battery died shortly after. I've since charged the battery and ultimately pulled one of the cooling fan relays. I did test my starting charging and battery system. Everything checks out, so the battery is in good condition and fully charged at this point. If it helps, this tahoe has dual climate zone for the front seat. It's manual, not digital. It also has rear climate controls as well.

I do not currently have a FSM or any knowledge where to buy one or download. I'd love to have access to electrical schematics to be able to start diagnosing this issue. Perhaps this is a common problem and there's someone I can be directed to inspect.


I should add, a week ago I did have my engine bay detailed, there is possibly water somewhere it shouldn't be.

 

[Fless]

The fan pins, IIRC, are at the bottom of the PCM connectors, so water migration there could cause this. Pull the PCM connectors and inspect, make sure they're dry.

 

[TotesMcGoats]

Ok, so I'll do that. Aside from removing the negative, is there anything else to do aside from physically removing the connector?

When I'm done. Is there any relearn procedures that need to happen?

 

[TotesMcGoats]

Well, found some corrosion in the connector. Used wd40 and q-tip to clean it up. Can't find any dielectric grease, so I'll probably wait to reconnect everything until I have some. Is this cause to pick up a new pcm? Is there something else I should be doing then what I've done so far? I still need to look at the harness connector and see how bad that corrosion is. I'm hoping not to bend it too much, I've heard the harness get brittle at the drip loop below the pcm.

 

[TotesMcGoats]

Well, looks like Flashmasters.com has my ecm for $119 shipped. I probably don't need one I'm guessing, but its affordable incase Indo need one.

 

[Fless]

I would clean up the contacts as much as possible with either Deoxit D5 or CRC QD Electronic Cleaner. WD-40 makes an electronic cleaner but it's not the regular WD-40 and I wouldn't necessarily use that regular stuff.

You may want to replace the water gaskets, too. And worry about the PCM later after you have success cleaning things up.

 

[SilverSport]

...and lean towards the DeoxIT...it will leave a small bit of lube for the connection...I've had to repeat other electrical connection cleanings when using CRC QD Electronic Cleaner...YMMV

Bill

 

[TotesMcGoats]

I used crc cleaner on the pins. I also used dielectric grease. Haven't fired it up yet. Will do that tonight. I'm hoping I don't have to do a security relearn, but we will see.

 

[TotesMcGoats]

So far so good. it fired right up without any relearning necessary. Drove about 40 miles thus far with two heat cycles. no codes. I didn't check all the monitors, but I will again this afternoon. it looks like the problem has been solved.

 

[Joseph Garcia]

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