Non stop fan noise

[gr8scott]

Shut down after a 10 mile or so drive, but I heard a fan noise. It was a hot day and traffic was slow, so I thought it was the radiator fan continuing the cool down. But when I went out to the garage an hour later, the noise was still on. There was no air flow to the inside, and the radiator fan was off too. The fan or motor-like noise seems to have come from the cowl just in front of the windshield. Again, I sensed no air movement.  No trouble  was indicated in the diagnostics. Battery was down to 8.6V.  Not knowing what else to do to stop it, I disconnected the battery, and that stopped it.  It's not a daily driver, so I can wait for pointers of what I should be looking for. ... appreciate any pointers.

[Ronnie]

It's likely the blower control module has gone bad and is keeping the blower motor running. It's a common problem. Did you check the defrost vents for air coming out of them? The airflow defaults to defrost when no vacuum is present.

Edited July 30, 2019 by Ronnie (see edit history)

[harry yarnell]

I've got good used modules for $37 post paid.

[gr8scott]

Is this  the item? (from the service manual)

[DAVES89]

ECC Power Module is the correct part

[Barney Eaton]

Blower motor fan controllers are getting harder to find at my pick-n-pull..........checking Rockauto,  they have new Delco controllers for $116

Looks like GM used it in everything but Chevrolet but only from around 1983 to 1993   it was used on cars that had "automatic" temp control (where you set the inside temp and the system maintains that temp)

[gr8scott]

Harry Yarnell was kind enough to sell me an ECC module, which arrived yesterday. However, it doesn't look anything like the graphic I posted from the service manual, and I'm having a hard time identifying it  under the hood . I'm barely semi-ambulatory, so I can only stay on my feet a few minutes at a time, and it would help tremendously if someone could point out the location on the attached picture.... and while I'm at it, which one of the three relays seen on the right controls the  ABS? I need to replace it because the light (yellow) stays on.

[Barney Eaton]

I do not know how to take your photo and add something like an arrow.......but see that white square behind the power steering reservoir,  that is the part.

The white square is actually a plastic lock so the connector will not come off....  from the outside all you will see of the blower motor controller is the top black plastic.

The heat sink is inside the duct.

 

It appears that someone has already replaced the relay closest to the brake unit.

Looking at your photo,  the relay on the left is the fuel pump,  the center relay is the brake pump relay, and the far right relay is the ABS unit.

It is unlikely replacing the relay will make the YELLOW ABS light go out.....it is more likely a wheel sensor,  but I am just guessing.

[Ronnie]

[gr8scott]

Progress report:

I've recharged the battery, reconnected it and the blower didn't come back on.  That was a relief... until I found  that it won't come on at all, confirming everyone's diagnosis.

I've located the  ECC power module but  I'm unable to do the contortions necessary to access the mounting screws in order to remove it. I'll find someone to do it.

 

 Question: Does the ECC module lift out after the screws are removed, or is it necessary to remove the blower motor itself (as suggested by the service manual illustration in my earlier post?

[2seater]

It lifts straight up and out. The screws are indeed a bit of a pain to get to.

[DAVES89]

You do not have to remove the blower motor and yes the screws are a bit hard to remove. But when you replace the screws only put two in, you don't have to install the rear most screw. The module will stay in place with just the two screws.

[gr8scott]

1 hour ago, DAVES89 said:

You do not have to remove the blower motor and yes the screws are a bit hard to remove. But when you replace the screws only put two in, you don't have to install the rear most screw. The module will stay in place with just the two screws.

Thanks, that's a relief.

[gr8scott]

I found a way to reach the screws, but first want to move the power connectors out of the way so when the screws are out I can lift he module out.  The white release tabs  move a little but not enough to  release the clip  holding onto the top edge of the connectors..... so close yet so far.

[harry yarnell]

They pull out, but will fight you.

I never reinstall these pins. If they break, so what.

Channel Locks can be your friend.

Edited August 14, 2019 by harry yarnell (see edit history)

[DAVES89]

Harry's right about those clips. A regular pliers will work as well. Not so important on the Blower Module, but I like them in place on the Master Cylinder.

[gr8scott]

After four days of intermittent struggles I managed to remove the term connectors and then the two screws holding the module down. I then spent the last two days trying to get a box or open end wrench onto that  third &*$@#^%^  screw in the back. Holding a tiny wrench blocks the view , so it's blind work. Even if I manage to somehow get the wrench onto it, there isn't enough room to make  a 1/6 turn.  How does one get to that rascal and with what tool?

[Barney Eaton]

This little ratchet works quite well in tight spaces and is cheap......Harbor Freight and other places carry them (often come in a kit with the sockets)

Also you can move that cable bundle to get more room.....in fact you must move it to get the module out.

[DAVES89]

I have done it with a 1/4" drive ratchet. I don't remember the millimeter size [7 nor 8mm?]

[harry yarnell]

It's a 7mm.

I either use a long spin-tite (like a screwdriver but with a 7mm socket on the end), or a short 1/4" 7 socket with a swivel.

Never put that screw back!

[gr8scott]

It's done. I found a flexible wrench extension at Harbor Freight, and after removing the stabilizer and  wrestling the jungle of cables out of he way  the last remaining screw became accessible. The module lifted right out and reassembly was a breeze. The air now comes on and turns off when ordered.  And then...just  to see what Gee-Whiz  circuitry I'd find inside   I decided to perform an autopsy on the bad module. Removing four screws  holding the two parts together, I may have stumbled onto the reason for its failure:  The thermal paste between the two aluminum surfaces  was dry and spotty at best, reducing conductivity and possibly causing  the unit to fail...... an uneducated and unsophisticated guess.      And because I had nothing better to do, I cleaned it up and applied a good coat of thermal paste I had left over from the last time I installed a new CPU in my PC. I didn't want to test my theory right then, but after reassembly I put it into a ziplock bag, and if I ever have an issue with the new one, I'll try it. Again, thanks for all the input and helpful suggestions, and thanks to Harry for supplying the needed part.

 

[Ronnie]

On 8/18/2019 at 9:27 PM, gr8scott said:

Even if I manage to somehow get the wrench onto it, there isn't enough room to make  a 1/6 turn.

 

I know this is a little late but... I have a 12 point, 7mm wrench that works much better than a six point wrench. It takes a little time but it will turn the bolt enough to eventually get it out.

Edited August 20, 2019 by Ronnie (see edit history)