SOLVED! Sudden Fan Death

[l008com]

Yesterday, without any warning, the fan in my truck stopped working. Not the engine fan, the HVAC fan. No AC, no heat. I can hear the compressor click on, but no matter what settings, no air comes out of the vents.

Any chance this is an easy fix that doesn't require pulling my whole dash apart?

 

[Mooseman]

Check the blower connector as well as on the module (or resistor pack). Both are accessible from under the dash after removal of the kick panel on passenger side. Don't forget the fuse (or breaker, I can't remember which)

 

[l008com]

Got any photos of diagrams of what I'm looking for under the dash?

 

[TJBaker57]

Already checked the 40 amp blower fuse?

 

[TobyU]

Often giving it a good smack on the blower motor will get it spinning again. Usually if it's the electrical or s[peed control module it will have high or at least some speeds.
When there is nothing, it can be a fuse but most commonly the motor is shot or stuck.

I have pulled many and lubed a lot without even removing them.
I have can of Lucas Chain Lube with the red nozzle and a long piece of tiny clear tubing I can feed into the space between the blower wheel to get to the shaft and oil it some. I also often pull the rubber tube out of the motor side and lube the rear bearing. I have even drilled a small hole of punched one with small sharp punch in the bubble over the rear shaft end to all oil there.

Most just put a new one in but unless I have a lifetime warranty...I am cheap and will keep getting as much life as I can out of it.

 

[l008com]

My mechanic also suggested punching it but where exactly do I punch?

 

[TobyU]

My mechanic also suggested punching it but where exactly do I punch?

On the rear of the motor in the middle but some have a plastic cover....a raised up area about 3/8 inch round. Do it on the side at 45 degrees.

 

[Mike534x]

Try @Mooseman suggestion. I had this exact issue 2 years ago. Got in, turned the A/C on and nothing coming from the vents. The compressor was making nose, but nothing came out of the vents, no matter what the speed was set at. Found a post on here from awhile back with someone having the same issue, and replacement of the blower module was suggested. I pulled mine out, and the connector was melted which seems to be common. The replacement came with a new one that you splice in, and once I had it installed everything was working again.

When the module is bad you'll have some speeds, or non at all. Here's a video on how to get at it.

 

[Mektek]

I relubed the front bearing by drilling a small hole in the front of the blower wheel near the shaft. Then a small spray straw can go through and leave a few drops of light oil near where the shaft goes through the bearing.

 

[l008com]

I haven't had time to look in to this yet. But today, at one point when I turned my truck on, the fan came on. It was stuck on a pretty low setting, 1 or 2 of 8. And wouldn't change speed no matter what I set the fan to. It was fine at that low speed for the whole drive. The next time I drove, it was back to nada. I don't think it's a mechanical problem with the motor, I think it's some kind of electronic problem.
But does the fact that it came back for a bit with only one speed, then died again, give any insight into what the problem may be?

 

[Mooseman]

If the speed isn't changing, I would assume the fan speed module (aka: resistors) is defective. Did you check for any physical damage on it and the blower motor at the connectors? I've had burnt connectors before.

 

[l008com]

Last night, speeds 1-4 all seemed to be working, and speeds 5-8 all seemed to be speed 4.
I haven't looked at anything yet, hopefully today I'll have some time to poke around.

 

[l008com]

Ok I poked around last night and here's what I found:

All connectors look mint. The fan does sometimes work on low speeds.
This leads me to believe it's a failed resistor and not a problem with the motor itself?

So the next logical step is to replace that resistor pack thing.
Also, just to be sure, that's the plastic thing with two small bolts on either end, right?
And the black roundish thing is the fan itself?

 

[l008com]

Can someone assist in looking up my exact part number?
My truck is an '08 LT short wheelbase, dual zone climate control with digital temperature control, and I believe I have rear AC. Looks like there are a LOT of different options for this part.

Also of the 10 or so resistors on rockauto, not one of them seems to have the same connector at mine.

 

[Mooseman]

You do not have rear A/C, like in the EXT, which do not exist for 08.

Blower motor module ACDELCO 1581773 . Plug is different because it will be replaced and spliced into the existing harness with the one included. I don't recommend any other brand.

 

[l008com]

Gah more soldering? Why do they have different connectors? That's a pain, I wish it was just plug and play.

Also there are hvac controls for my back seat passengers on the back of the center console, that is not what rear ac is?

 

[Mooseman]

Also there are hvac controls for my back seat passengers on the back of the center console, that is not what rear ac is?

Nope. That's just air pumped from the front HVAC. All SWB have it. EXT/XL have a separate evaporator, heater core, plenum and blower for the rear only.

 

[Mooseman]

Gah more soldering? Why do they have different connectors? That's a pain, I wish it was just plug and play.

I think it's because it's an improved version and that a lot of times, the wiring or connectors are burnt.

 

[l008com]

I just removed my old resistor module and opened it up. I'm looking at the board but everything looks fine. Do people ever repair the boards? I'm not sure where you'd begin given no obvious visual damage though. But if that big three-pinned component is what's likely to be bad, I could probably solder a new one of those on easy enough!

FZTJjf0.jpg

 

[l008com]

An electronics buddy has suggested which component has probably gone bad and found a replacement online for $3, so i'm going to see if I can solder that new chip on to the board to replace the bad one and not have to do any under the dash wire soldering, especially since all my wires and connectors look perfect, no signs of heat at all. Spent $12, maybe save $40. Fingers crossed.

 

[christo829]

Which component did he suggest, the FET?

 

[l008com]

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[christo829]

Yep, that's the FET. Hadn't even thought about that because when it did fail, it usually caused the fan to keep running, not cut off. Hope it fixes the problem!

 

[l008com]

Originally I was getting no fan, then i started to get only slow speed fan. It's kind of random what I get, but I never get normal operation. But I don't think it's a fan problem given that fact it works sometimes but only at low speeds and never makes any weird noises or anything.

 

[Mooseman]

If it does work, would be cool if you could do a write-up. We all want to save some money

 

[l008com]

If it does work, would be cool if you could do a write-up. We all want to save some money

Well, I suppose if you are very good at soldering, this may have been a cheap fix. I don't know because after countless hours, I absolutely cannot get this chip soldered onto the board. At least not without shorting the three pins into one giant glob of solder. Looks like I'm just going to give up and order the full $50 module :-/

 

[Blckshdw]

Well, I suppose if you are very good at soldering, this may have been a cheap fix. I don't know because after countless hours, I absolutely cannot get this chip soldered onto the board. At least not without shorting the three pins into one giant glob of solder.

A lot can also depend on the equipment you're using. When I first got started with LEDs, I had an entry level Radio Shack (remember them? lol) iron, that was really difficult for small stuff. Decided to upgrade to an adjustable temp iron, that came with an assortment of tips with different shapes and sizes. That made all the difference in the world when I started dealing with soldering SMD components to PCBs, or making my own panels with perf boards. So really, it might not be entirely your soldering skills at fault here

 

[l008com]

Bad news peeps.
I installed the new resistor module today. Splicing the three wires was a LOT easier than trying to solder the chip on to the old board.

Welp, NADA. Not a single spin of the fan. Not even the slow speed spinning I would sometimes get before. But the fact that sometimes it spun slowly before, but not in the higher speed settings, is such a strong indicator that the problem was the resister module.

So the question for now is:
Is that wrong, and is it the fan after all?
Or did I get a dud resistor module?
Is there some definitive way to diagnose this?

 

[Mooseman]

Try and put direct 12v+ to the fan and see if it spins. Is power getting to the blower module? After that, check the wiring from HVAC controls to the blower module. At this point, I would try replacing the HVAC control module with a used one.

 

[l008com]

Interesting update. I was driving home today, thinking about how to remove the fan when I get home, and then thinking about how I would most easily supply power to it to see if it worked. I still have the original resistor module, I could cut the wires off of that and strip the ends, just like I did with the wires under the dash. Those ones sparked when I snipped them because I did not disconnect the battery. Hey wait, those ones sparked, I shorted them. Maybe I just blew the fuse when I soldered up the new harness!

..... then I checked and confirmed the same 40 amp fuse I checked when all this began, wasn't blown then but is now. I swapped another one over just to test and confirmed, HVAC fan is working! Now I just need to pick up a new fuse and re-assemble everything and I'll be good to go! Woohoo i love crossing things off the ol' to do list.