Hello fellow grease-hounds. I am a lowly novice in wrenching/trouble shooting skills. I only ask for help because I’ve got a wall and I’m broke and jobless. If anyone can point me in the right direction, I’d be in your favor.

I have tried to trouble shoot this problem and researched/Tube’d of the Yu…& I’ve hit a wall. I’ll try to lay out the problem, what I’ve done to date to trouble shoot, and then me begging for help from you sirs and ma’am’s.

Problem: 2005 Toyota Highlander, V6 fwd. Turn off the motor and Fan 1(driver side) at the radiator will kick on and run at high speed (important note) until the battery goes dead. This isn’t a radiator fan kicking on at low speed at engine shut-off.

Trouble shooting to date:

  • checked all fuses, good
  • pulled Fan 1 Relay and it shuts off fan
  • used light test on a rope (first time) and removed Relay for Fan 1 to test current at the relay connection. (***I think I need help here, with wiring diagram and troubleshoot).
  • I tried to find a short in EB1/EB2. Could not find a noticeable short messing with the connections and they were clean when opened (my fingers are bleeding ha).

Research:

https://www.justanswer.com/toyota/hzt2o-2004-toyota-highlander-cooling-fan-appears.html

https://m.youtube.com/watch?v=RguLHiWNIMU

Lizard brain idea: Maybe the fan is grounded through EB2 or EB1? I can’t see any obvious signs of rust or damage through.

  • waynep712222@alien.topB
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    10 months ago

    sent you a Private message…

    i would want to see if the 10A Heater fuse is staying powered with the key off… that is what i would see to keep one of the fans on…

    fan relay 1 and fan relay 2 are controlled by several devices…

    engine temp switch number 1… the pressure switch on the A/C system A3. and the PCM…

    the water temp switch number 1 seems to show in the passenger side radiator tank… hmm, marked W3 on the diagrams…

    water temp switch number 2 is on the drivers side area of the cylinder head… i am looking at a diagram… marked W4