Both Fans Run All the Time...Solution Question, 5SFE Options

[FrankB2]

Hi Guys.
Both of my 1997 2.2 5SFE fans run constantly, even after turning the ignition to "On" in the morning, but not starting the engine. A quick search here suggests the problem is the Engine Coolant Temperature Switch, located at the bottom rear of the radiator. Before draining my coolant, I thought that if this is the problem, disconnecting the wire from old and connecting it to the new without installing it into the radiator should keep the fans off with a cold engine (or just turning the ignition to ON without starting a cold engine). Does that sound about right to anyone? Also, does this look like the right part:
http://shop.advanceautoparts.com/webapp/wc...bwd_18970379-p# It looks right to me, but Advance Auto has given me the wrong parts before.... Oh Yeah! Do the threads need Teflon tape, or any other type of sealant?
TIA!!!

[ILoveMySilly97]

That's incorrect. If you buy a new one and don't plug it in and screw it into the radiator. The fan well still be on.

[FrankB2]

I was hoping that just plugging it in would indicate if that was the solution. Oh well....time to drain my coolant.

[Smaay]

That's incorrect. If you buy a new one and don't plug it in and screw it into the radiator. The fan well still be on.

thats not what he was asking

I was hoping that just plugging it in would indicate if that was the solution. Oh well....time to drain my coolant.

yes if you just unplug from the sensor on the radiator and plug into the new sensor in your hand, turn the key to the on position and the fans should NOT come on. if they do, you might have a broken wire somewhere in the circuit

[FrankB2]

I'm just about to leave for the parts store, and I like your answer, Smaay. Let you know what happens...............

[FrankB2]

Well.... That didn't work. I took the fan out, and plugged in the new switch, but both fans still came on with ignition turned to ON but engine off. I did get some nice burns, however.

[Syaoran]

Your fans were most likely hardwired into the ignition switch at one point then, or perhaps there's a bad relay.

[Batman722]

Mess with the AC at all lately ?

These is a pressure switch close to the firewall on the pass side, connected to the AC lines and into a wire harness. If it's unplugged the fans will stay on with ignition.
Make sure it's plugged in.

[FrankB2]

Thanks Guys! I'll check for the pressure switch, but haven't done anything with the AC (which works fine). I first noticed this a few weeks ago, when the temp gauge went past the halfway mark briefly. I turned on the AC to see if the fan would kick in, and bring the temp down. The fans came on a few seconds later, and the temp gauge went back to where it usually reads: just past 1/4. The outside temp was in the upper 90's then, and it was a blip that lasted for less than 5 minutes total.

My niece's fiancé is a mechanic, and just got a job at the local Toyota dealer. The place has SEVENTY BAYS! The customer waiting area has lounges, a cafeteria, and a small movie theater! It's been a dream of mine that he worked there instead of the local Honda dealer, and the dream has come true. He told me that they were too busy to squeeze me in, so I decided to tackle this myself. Not an easy job, unless you want you don't mind replacing things that might not need replacing.

I'll post whatever I find.......

EDIT: Batman, I found the pressure switch going into the AC line, and disconnect/connected it. Nothing changed, but it was a quick job.

This post has been edited by FrankB2: Sep 4, 2013 - 6:52 PM

[FrankB2]

ARGHHHHH!!! I really did it now. I decided to yank the plug on the coolant temp sensor (the one near the throttle body), with the car running. The CEL came on, and I pulled the EFI and ECU fuses hoping to reset it. After I started it again, the idle was alright w/o AC, but was super low with AC. With the AC on and the car in gear (automatic), the relays for fans 2, 3, and AC compressor were all clicking open and close.

I hate this.....LOL!

This post has been edited by FrankB2: Sep 4, 2013 - 6:53 PM

[Smaay]

check your ECU and wiring grounds. my All-Trac did that when one of the grounds on the back of the intake manifold came loose

[FrankB2]

Hi Smaay,
It seemed weird that the idle was dropping with the AC, so I did a search here that led to an Autozone idle up valve check and diagram. I went out to the car, and it was still around 400rpm in drive with the AC on, so I disconnected the power to the idle up valve, and reconnected it. INSTANT FIX! Now it runs just a hair above 1000 rpm with AC on in neutral, and 750 rpm in drive. Took it out for a test ride, put it through the paces, and all is well. Both fans still run all the time, but my idle is sweet again.

[Roadrash]

I know its a different path to fix a problem.... but they do sell a Thermomatic Switch Kit for Electric Fans


http://www.4wd.com/Heating-Cooling/Thermom...FS9dQgodDTIAIA#

[FrankB2]

Yeah! I saw one of those on Autozone's website. Seems like a simple solution. I googled this problem, and someone said they used a toggle switch when their fans ran all the time. I unplugged the AC side fan yesterday, since the temps aren't going above 75 degrees right now, and it's a convertible anyway.

[FrankB2]

Update:
I tested the coolant temp switch in the radiator for continuity, and it has continuity when the engine is ice cold. I bought the same switch from Advance Auto a couple days ago, and it had continuity when I tested it out of the box, so I assumed that the switch in the radiator was good. It's my understanding now (YOUTUBE and Google) that the switch should not have continuity when cold. I wouldn't be surprised that a cheap switch from Advance Auto might be bad out of the box, so I'll try another switch there, or buy a Toyota switch.

[Galcobar]

Toyota designed the system so that if the fan temperature switch fails, the fans run constantly -- better to have a cold radiator which still allows the thermostat to control temperature than to boil the coolant.

Unfortunately, that's not your problem. The switch should have continuity when cold (below 83C) so that it can interrupt the fan circuit and turn the fan off.

From the factory repair manual:
1. INSPECT WATER TEMPERATURE SWITCH
(4A–FE)
(a) Using an ohmmeter, check that there is no continuity between the
terminal and switch body when
the coolant temperature is above 93°C (199°F).
(b) Using an ohmmeter, check that there is continuity
between the terminal and switch body when the
coolant temperature is below 83°C (181T).
If continuity is not as specified, replace the switch.
(3S–GTE and 5S–FE)
(a) Using an ohmmeter, check that there is no continuity between the
terminals when the coolant temperature is above 93°C (199°F).
(b) Using an ohmmeter, check that there is continuity
between the terminals when the coolant temperature is below
83°C (181 °F).
If continuity is not as specified, replace the switch.

[FrankB2]

That's what I've been suspecting to be the case, and why I haven't ordered another switch from the dealer. I was going to go to another parts store and test their switches for continuity, but you've saved me time there. Today's high is supposed to be 93 degrees, but it will start dropping to highs of 70-something soon. Unplugging the AC fan helped keep the temp gauge around 1/4 from the bottom this past weekend, but who feels like playing that game? My man at the Toyota dealer didn't believe that there was even a coolant temp switch, so I don't know how much help he'll be. I have a diagram for testing all the fan relays, but I'm not sufficiently motivated to do that yet.....

Thanks for the info, Galcobar!

[FrankB2]

Double post... See post below.

This post has been edited by FrankB2: Sep 12, 2013 - 1:02 PM

[FrankB2]

Yeehaaa..... Think I've got it. Found a troubleshooting diagram for the relays, and Fan Relay No. 1 looks like it should have continuity without power across terminals 1 and 2, and 3 and 4. I'm getting continuity between 3 and 4, but no continuity between 1 and 2. My son is an Avionics Tech in the USAF, and he concurs with my reading of the diagram, and the continuity test. I ordered a new relay from Toyota, and it should be here tomorrow ($83!). Here's to hoping my fans stop running when the lows are in the 40's this weekend.

Diagram: http://bgbonline.celicatech.com/94_6gmanua...0four%20cyl.pdf

EDIT!!! ARGHHHHH!!!! I thought I'd check fan relays No. 2 and No. 3, and tore the case off one, and crushed the case on the other! I had the retaining tabs pulled out, but these relays were not nearly as robust as No. 1. Of course the local parts stores don't carry them, and Toyota can't order past 4pm. I can get them in by Saturday morning, and I'm sure that'll be another $100 minimum. Still trying to decide whether to kick myself or the car.

This post has been edited by FrankB2: Sep 12, 2013 - 4:53 PM

[Special_Edy]

You should pull the efi relay or another fan relay and swap it for the one you suspect is defective. Its a free way to test your relays.

And the simplelist way to explain the fan switch is that-
Fans off - closed cicuit
Fans on - open circuit

Just stick a piece of wire or a paperclip between the two contacts on the fan switch plug to see if the fans shut off

P.S.
Use a screwdriver to pry underneath the relay while you tug at the base(you cant pull on the top/case)and your local junkyard will sell you a fistfull of Toyota relays for less than beer money.

This post has been edited by Special_Edy: Sep 12, 2013 - 10:16 PM