fan problems

[chet]

I have a 2008 mercury marquis. The EATC system fan stays on high all the time, even when the unit is turn off. Sometimes air will blow out the dash vents. What is my problem, and how can I fix this.

chet

[RubberCtyRauder]

prolly o rings need changed

http://mercurymarauder.net/forums/showthread.php?t=80673

[chet]

Will o rings fix the problem, I don't understand.

[RubberCtyRauder]

it's a vacuum system and when the o rings dry rot they leak causing issues as these. common problem. read this thread as well. You need silicon o rings metric 007

http://mercurymarauder.net/forums/showthread.php?t=36922

[RubberCtyRauder]

The staying on high could be the blower motor resistor, BCM, the coming out the dash vents is likely the o rings, so you prolly have two issues.

[RubberCtyRauder]

here is more on the BCM and staying on high speed.

http://www.crownvic.net/ubbthreads/ubbthreads.php?ubb=showflat&Number=2841446

[fastblackmerc]

OP you have two problems.

1 - air coming out of the wrong vents is most likely bad o-rings in the EATC.

2 - fan stays on high could be either the BCM or the EATC control board.

[Mr. Man]

Fix the O-rings first and see if the blower speed goes back to normal before digging into the BCM

[RF Overlord]

O-rings have nothing to do with fan speed.

[Mr. Man]

O-rings have nothing to do with fan speed.On our way to MV14 the O-rings in Ms.D's car finally crapped out and the car couldn't figure out where to send air. Vents, dash, floor, combos. In the Auto setting it would blast the fan and constantly redirect the air. I had Russ swap the O-rings out and now it works fine. Never touched the BCM. Just advising the OP to tackle the O-rings first and see what happens.:)

[Bluerauder]

On our way to MV14 the O-rings in Ms.D's car finally crapped out and the car couldn't figure out where to send air. Vents, dash, floor, combos. In the Auto setting it would blast the fan and constantly redirect the air. I had Russ swap the O-rings out and now it works fine. Never touched the BCM. Just advising the OP to tackle the O-rings first and see what happens.:)


For me, the indicator was that the A/C would divert to defrost under acceleration. I could hear the switchover as soon as I put a load on the engine. Russ did the O-ring fix for me on Sunday in the parking lot of MV9 in Hershey.

[Mr. Man]

For me, the indicator was that the A/C would divert to defrost under acceleration. I could hear the switchover as soon as I put a load on the engine. Russ did the O-ring fix for me on Sunday in the parking lot of MV9 in Hershey.I remember that. Those were Ms.D's rings, but at the time her EATC was working fine. Russ did my Black car that day too.

[RF Overlord]

In the Auto setting it would blast the fan and constantly redirect the air. I had Russ swap the O-rings out and now it works fine. Never touched the BCM. Wow...that's bizarre...or "bzah" as we say in Boston.

The only thing I can think of is that by disassembling the guts something was disturbed in the head unit that corrected whatever was causing the fan issue.

[fastblackmerc]

Wow...that's bizarre...or "bzah" as we say in Boston.

The only thing I can think of is that by disassembling the guts something was disturbed in the head unit that corrected whatever was causing the fan issue.

Not really.............. If there is a vacuum leak, like the o-rings, the system will go into fail-safe mode, defrost, heat and max fan.

[RF Overlord]

I thought fail-safe mode only meant it would direct all the air to the defroster, not that it would turn on the fan. I learned something here today... :D

[Mr. Man]

The lesson learned here is if you haven't replaced the rubber O-rings in the EATC with silicone ones, you should.:)

[Turbov6Bryan]

Not really.............. If there is a vacuum leak, like the o-rings, the system will go into fail-safe mode, defrost, heat and max fan.

Funny is my dads silver birch went to max fan when the orings went bad, I did the orings and just figured the bcm FIXED itself

4 orings and it's been fine ( knock on wood) no fan on high all the time


Cool. Learned something new today

[fastblackmerc]

The lesson learned here is if you haven't replaced the rubber O-rings in the EATC with silicone ones, you should.:)

Correct.... it's not will they go bad... it's when will they go bad.

[Turbov6Bryan]

Speaking of those red silicon 007 orings

I bought some from oring.com or oring..... they are brittle a year later right out of the sealed bag

Seems like they are super easy to break now that they are older, anyone else having this issue?

I might just go with a white hard plastic oring in the future, they won't snap

What durameter oring you guys buying?

Thanks