Cooling fan issues

Discussion in 'Drivetrain, Exhaust and Electrical' started by antman450, Jul 10, 2018.

  1. antman450

    antman450 TMO Race

    Messages:
    397
    Likes Received:
    260
    Joined:
    Feb 26, 2017
    Location:
    Orange County, California
    I have an 11 GT that I stripped out completely and is effectively not for road use (however still drivable on the road). Nonethelss, I was drving it on the street in traffic and it overheated. I tested by letting it idle for a long time sitting still and the car started to overheat and the fan never came on. I am thinking it may be a bad fan motor, so I will need to test this. I have already tested all relays and fuses. I did not however check the fan relay. I don'yt know where it is. If someone could tell me, that would be great. But I was thinking if the fan motor is good I would put in a manual fan switch.

    Any ideas on this? Should I just run some 10 guage wire straight to the fan and then a two pole switch on my center panel? Or is there a better way?
     
  2. ArizonaBOSS

    ArizonaBOSS Because racecar. Moderator

    Messages:
    8,190
    Likes Received:
    1,814
    Joined:
    Dec 6, 2010
    Location:
    Arizona, USA
    http://iihs.net/fsm/?d=711&f=033 - Cooling Fan.pdf

    The relays are in the engine bay fuse box according to that diagram. Not sure which ones they are but the Owner's Manual should say.
    I have never had a problem with the fan activating (typically comes on at 183*F), check those relays and the wiring coming out of the fuse box that runs to the fan itself.

    Also if there is no problem with the wiring, I strongly suggest going to the SVT fan assembly.
     
  3. BigTaco

    BigTaco TMO Addict

    Messages:
    652
    Likes Received:
    195
    Joined:
    Nov 27, 2014
    Hella this^
     
  4. antman450

    antman450 TMO Race

    Messages:
    397
    Likes Received:
    260
    Joined:
    Feb 26, 2017
    Location:
    Orange County, California

    I switched the relays around and everything else worked fine, so those should be good. All the relays are the same. I swapped them with the other relays that work. I forget exactly what those were for but I tested the component they control and they worked fine. The wires all look good too. I will test the fan motor but ultimately I would like to put it on a manual switch. Anyone know of a good way to add a relay in (basically which one to use) that I can connect to a toggle switch on my center panel?
     
  5. BigTaco

    BigTaco TMO Addict

    Messages:
    652
    Likes Received:
    195
    Joined:
    Nov 27, 2014
    I would just replace the fan assemble since the toggle doesn’t really fix the problem. That assembly may stop working even with a toggle at some point in the not so distant future....
     
  6. antman450

    antman450 TMO Race

    Messages:
    397
    Likes Received:
    260
    Joined:
    Feb 26, 2017
    Location:
    Orange County, California
    Fan is bad. Got the SVT fan. What do any of you guys think is the easiest way to add a manual switch. Should I just add a wire to the relay in the fuse box? I want to be able to turn it on when I feel like it as well.
     
  7. ArizonaBOSS

    ArizonaBOSS Because racecar. Moderator

    Messages:
    8,190
    Likes Received:
    1,814
    Joined:
    Dec 6, 2010
    Location:
    Arizona, USA
    My GUESS is that the best way to do this would be to tap a line into the wire that turns on the OEM relay for the fan, that way you are not overloading the fan when/if the ECU commands the fan to activate even if you already have the fan switched on manually (as opposed to two separate power lines to fan).

    12V from battery --> 5A fuse --> Switch --> Splice/tap OEM fan relay signal line.

    Attempt at your own risk--haven't thought this out too much and suggest you do your own research before attempting.
     
  8. TMSBOSS

    TMSBOSS TMO Addict

    Messages:
    4,085
    Likes Received:
    1,204
    Joined:
    Aug 23, 2011
    Location:
    Illinois
    Diode up stream to protect processor?
     
    ArizonaBOSS likes this.
  9. antman450

    antman450 TMO Race

    Messages:
    397
    Likes Received:
    260
    Joined:
    Feb 26, 2017
    Location:
    Orange County, California
    So, bought a new fan (GT500) and it still does not turn on. I am over troubleshooting this and going to just add a manual switch. Any ideas on a relay part number?
     
  10. racer47

    racer47 All I got left is fast

    Messages:
    200
    Likes Received:
    210
    Joined:
    Jan 8, 2017
    Location:
    SE WI
    You need something like this. I got this to do the same thing, add a manual fan switch. I just have not got around to it yet.
    relay.jpg
     
  11. antman450

    antman450 TMO Race

    Messages:
    397
    Likes Received:
    260
    Joined:
    Feb 26, 2017
    Location:
    Orange County, California
    I got this and I am going to run 10 ga wire from battery through switch and 40 amp fuse. Then I will run a ground through a switch in my center panel.

    https://www.summitracing.com/parts/aww-500532

    @ArizonaBOSS I thought about your idea but I don't want to try to find the darn wire. I am sure I cut something somewhere I should not have. The only other thing would be a bad thermostat or sensor. I really think the former is far more likely as I got somewhat overzealous with the cutting. LOL
     
  12. DocB

    DocB TMO Advanced

    Messages:
    119
    Likes Received:
    36
    Joined:
    Sep 17, 2013
    You may want to consider checking your plastic fuse box and make sure it is not "tweeked", or one corner sittting on the inner fender housing.
    This will cause a relay to work loose (if ever so slightly) and the fan will not come on.
    Next time the fan does not come on, try pressing down hard on the high speed fan relay in the box and see if the fan turns on.
     
  13. Grant 302

    Grant 302 OPM Spent: $665,833 Moderator

    Messages:
    6,793
    Likes Received:
    1,719
    Joined:
    Nov 23, 2011
    Location:
    In the OC
  14. Grant 302

    Grant 302 OPM Spent: $665,833 Moderator

    Messages:
    6,793
    Likes Received:
    1,719
    Joined:
    Nov 23, 2011
    Location:
    In the OC
    Yeah...the pcm signal line closes the negative side of the relay solenoid. Don't hook it up to the battery. Might damage the PCM even with a 5A fuse.

    Adding a switch to the signal line needs to connect to ground. Doesn't need to be fused IMO as it's all fused on the hot side. Grn/blu #34 on the PCM for the low speed fan.
     

Share This Page