Car Running Hot!

Discussion in '2005+ Mustang GT 4.6L Tech' started by scramblr, Jun 17, 2021.

  1. scramblr

    scramblr Senior Member S197 Team Member

    Noticed my fan wasn't working and attributed to high temp relay and changed it. Temp seemed o.k. until the weather went into the 90s. Car was running hot, low speed fan not turning on. Swapped relays around, checked the 40A fuse and BEC, all are fine. I have jumper on the high speed fan and it did turn on the fan.

    Swapped out w/ 13/14 GT500 fan. This morning was 80* and drove 30 minutes w/ AC on to work and car temp stayed around 190*. Coming home w/ AC on, temp was 90* and 10 minutes from work car overheated. Added water, turned on the high speed fan and made it home. Temp stayed at 190*.

    I ran the car in the garage and high speed fan comes on at 218* and off at 208*, tried it multiple times. Fan does cycle on and off w/ the AC and/or defroster on. It does not come on at any other temp, so no low speed fan?

    Guessing temps in the tune are stock, it's locked so I can't see the settings. Any idea why the low speed fan isn't turning on?
  2. jewc75

    jewc75 S197 Junkie S197 Team Member

    Have you tried a wire from the positive side of the battery to pin 14 on the CCRM?
  3. scramblr

    scramblr Senior Member S197 Team Member

    Pretty sure there is no CCRM in 05+, all that stuff should be in the BEC now. Then again, start getting into electrical shit and my brain fogs up, so I could be mistaken. That's why I just bought a new fan instead of trying to run down if it was the resistor in the old one.
  4. Dino Dino Bambino

    Dino Dino Bambino I have a red car

    Have you checked the fan resistor? It's a fairly common failure point.

    You're thinking of the SN95.
  5. scramblr

    scramblr Senior Member S197 Team Member

    I lied...BEC is not ok. I had only looked at it from the top. Inside is another story. Is there a part number for just this piece and I can switch the wires over to it? If not, what do I need, a new harness for that middle piece? Or do I need a whole new BEC? Anyone have any part numbers?


    Last edited: Jun 18, 2021
  6. MrBhp

    MrBhp Member

    A fairly common problem. Take the fan load completely out of the box. Run a stand alone fuse and relay. I would shoot you some pics but once again I'm 2000 miles away from my car.
  7. scramblr

    scramblr Senior Member S197 Team Member

    That's what I'm working towards. For now I pulled the low speed relay and manually switching on the high speed relay.

    I've been looking through threads and doing the external fuse/relay is the way to go. Just need to figure out how to do it. Not electrically inclined, but can do just about anything if I can see how to do it. The below pic is as close as I've gotten, but just need to figure out all the wires.

  8. scramblr

    scramblr Senior Member S197 Team Member

    Took another route. Went to a junkyard and got the end of the harness for $3. Cut the burnt wire from my harness and spliced another (same gauge) with a fresh pin from the donor. Swapped all the wires to the donor plastic thingy and all is well. I think with the upgraded fan, the resistor problem should not re-appear, so the BEC should be o.k. Time will tell.
  9. 86GT351

    86GT351 forum member

    sadly this is a very common issue.
  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.