BCM issues....

[91 SHOplus]

Hey Gang, I did a search which answered some of my questions but I need a little more info. Here goes....

We had a real gulley-washer of a rainstorm yesterday and the defroster wouldn't turn off. The EATC head said OFF, but it was still blowing.

I have read that this is indicative of the BCM - blower control module, and can happen in high humidity, or if actual water leaks onto the unit. I have also read that this will fix itself when it dries out. Cool, because my local Ford dealer wants $210 for a new one. eek! Yikes!

Here's where it gets weird, When I turn the fan speed down all the way, the unit changes from defrost to max A/C.

I did a self-test on the EATC head, (i did it once before last summer and got an 02 - blend door code) and now it reads 888 - no problems found.

shrug WTF?

 

[NiNeTy Fo SHO]

My BCM was making the fan run all the time even when the EATC said off. I ran the self-test on the EATC and it said 888 just like yours. I went and got a different EATC and it did nothing, fan still blew at high speed constantly. Went and got a different BCM and fixed it. Now the fan does what the EATC says.

By the way...I went to a local junkyard and found a EATC and the BCM out of a sable or something...ended up costing me like 10 bucks for both...I have had both of them in for over a year and still no problems.

Hope this helps...

 

[luigisho]

Rainstorm is the real tipoff. Somehow the module is vulnerable to shorting when large amounts of rain filter through the car. The unit is not sealed well enough. Find another parts car somewhere and get the piece. All the Taurus sedans and their cousins used the same system.

 

[91 SHOplus]

Thanx guys, but you're not getting the gist of it. Let me rephrase the question...

I understand that the BCM is acting up and still blowing through the defrost vent after the head is off.

BUT, The real questions are...

• <font size="2" face="Verdana, Helvetica, sans-serif">Why would my EATC with a known 02 code all of a sudden show 888?
• <font size="2" face="Verdana, Helvetica, sans-serif">Why would the fan speed selection change modes on the head itself?

<font size="2" face="Verdana, Helvetica, sans-serif">
I understand that the blower still spins when the BCM goes, but why the other problems? Aren't they more head-related instead?

I thought the BCM just controls the speed at which the fan blows? Am I missing something?

<small>[ August 12, 2003, 12:23 PM: Message edited by: 91 SHOplus ]</small>

 

[Mr Anonymous]

A shorted VBCM might be screwing up your EATC resulting in the additional oddities you're seeing. First replace the VBCM, and then see what (if anything) else needs to be addressed.

 

[91 SHOplus]

Ooooooooooh!

So it is responsible for more than just fan speed. Ok, That makes sence. The damn thing dried out and has stopped blowing, so I'll wait this out untill it rears it's ugly head again.

Thanx.