Results 1 to 9 of 9

Thread: EATC Fan Speed Erratic.

  1. #1

    EATC Fan Speed Erratic.

    Can anyone tell me why my AC/Heat fan speed is irregular when set to anything other than maximum speed using the wheel to the right of the EATC?

    If I set it to max, I hear a relay click and it's on high speed and consistent. If it's set to any other speed, the fan speed varies intermittently and will jump to anything between full speed to low speed...and it seems to change when I hit bumps in the road. It never turns off. When it picks a new speed, it just goes to that speed nicely and stays there.

    If I had to guess, I'd say the cabin temperature sensor or circuit is misreporting the interior temperature or something like that.

    Self test passes with no faults.

    Has anyone seen this?

    Thanks,

    Byron

  2. #2
    Join Date
    Mar 2009
    Location
    on the outside looking in
    Age
    45
    Posts
    1,585
    THE BCM IS FAULTY MOST LIKELY

    waiting to be blown
    You can run all your life but not go anywhere
    positive manifold pressure leads to coitus

  3. #3
    Join Date
    Jul 2012
    Location
    Seattle Washington
    Posts
    911
    when you select the fan speed using the wheel the EATC does not control the fan speed based on cabin temperature - so you can forget the cabin temp sensor.

    Based on the description of your symptom it sounds like the switch is erratic. I've seen blower motor resistors fail several ways, but never have I seen them erratically change speeds on its own.

    Either way your top two things to look at are the EATC(and its build in speed wheel switch) or the blower motor resistor.

    good luck.
    I eat apples until my stomach feels much more full than its normal.

  4. #4

    BCM was it; and now it's fixed.

    Thanks guys, I dug into it last night and resolved it. The BCM (as yjmud suggested) was faulty, again. 150K miles (or so) ago, the fan died completely and I took the BCM out and found that the solder joints on the main big power lugs was cracked. I soldered that, and it worked fine until now (near 200K miles). This intermittent fan speed issue was another cracked solder joint; this time on one of the smaller pins on the same connector. I cleaned off all of the solder mask to bare copper around all the pins this time, and soldered the hell out of everything. This morning, the fan operates normally. Sorry the pictures aren't better; I took them for myself...didn't think of sharing them until now.



  5. #5
    Join Date
    Jan 2004
    Location
    Somewhere in the N.C. Triangle
    Age
    68
    Posts
    26,250
    Common panther-platform problem.
    “When you can’t make them see the light, make them feel the heat.”
    Ronald Regan

    "The only way to deal with the Islamic State - these blood thirsty, blood-drunken, terrorists -
    is to kill them, keep on killing them, until you kill the last one, then you kill his pet goat."

    Lt. Colonel Ralph Peters

    “Be polite, be professional, but have a plan to kill everybody you meet.”
    "I come in peace. I didn't bring artillery. But I'm pleading with you, with tears in my eyes, if you **** with me, I'll kill you all"
    General James Mattis




  6. #6
    Join Date
    Apr 2011
    Location
    Statesville, NC
    Age
    33
    Posts
    2,164
    guess I'll be pulling out my BCM, I have a similar issue but I only get full blast only. It shuts off fine but the dial on the EATC is useless right now

  7. #7
    Join Date
    Mar 2009
    Location
    on the outside looking in
    Age
    45
    Posts
    1,585
    I AM GLAD YOU GOT IT FIXED

    waiting to be blown
    You can run all your life but not go anywhere
    positive manifold pressure leads to coitus

  8. #8

    Dead fan

    Quote Originally Posted by jwibbity View Post
    guess I'll be pulling out my BCM, I have a similar issue but I only get full blast only. It shuts off fine but the dial on the EATC is useless right now
    When my BCM failed the first time, I would intermittently lose the fan completely. Not a speed problem; it would shut off completely. It would not even function with the wheel at the max setting. That was cracked solder joints on the two large terminals in the BCM at the connector. The intermittent speed problem was the solder joints next to it that I didn't have the foresight to reinforce; they failed many years later.

  9. #9
    Join Date
    Aug 2008
    Location
    Auckland
    Age
    59
    Posts
    40
    I have this blower issue too; I posted a comment earlier under http://www.mercurymarauder.net/forum...d.php?t=100629

    I guess I will pull out the BCM and check the soldering...

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Erratic Idle/Acceleration/Deceleration - Need Help
    By HotRaud90 in forum Shop Talk
    Replies: 11
    Last Post: 09-29-2015, 12:17 PM
  2. Replies: 3
    Last Post: 11-17-2014, 06:00 PM
  3. EATC speed resister
    By 4play in forum Shop Talk
    Replies: 2
    Last Post: 02-19-2010, 11:05 PM
  4. Erratic idle
    By HITEKBALANCER in forum Shop Talk
    Replies: 20
    Last Post: 11-06-2008, 05:35 PM
  5. Anyone installed a stick (5-speed or 6-speed) in a Marauder yet???
    By Professor in forum Community Discussion
    Replies: 9
    Last Post: 09-10-2007, 04:53 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •