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Ask Joshua Haynes Your Own Question
Joshua Haynes
Joshua Haynes,
Category: Toyota
Satisfied Customers: 273
Experience:  Lead Technician/ Manager at Precision Tune Auto Care
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I have a 2004 Toyota Camry 4Cyl. When the car runs while the

Customer Question

Hello. I have a 2004 Toyota Camry 4Cyl. When the car runs for a while the tepature gauge will go up about 3/4 the way to the H and stop there when it reaches Operating temperature or above. (It never makes it to the H) The fans DO NOT COME ON. If i turn the AC on the fans WILL COME ON, I have replaced the Engine coolant sensor, Thermostat and new Toyota Antifreeze. I have shaped out the relays and they appear to be ok. I went to auto store and there is a "Radiator Temp cooling switch" They have but I can't locate that anywhere on the radiator. Do you have any suggestions or a diagram??
Submitted: 11 months ago.
Category: Toyota
Expert:  Ted Ritter replied 11 months ago.

Thanks for posting your question

There is a coolant temp sensor for the fans, it should be in the bottom tank of the radiator, it will have an electrical connector on it with two wires, with the key on ppulling the connector of the fan should run constantly, if it does that switch is the problem.

Customer: replied 11 months ago.
Hey Ted,do you have a diagram of this location? When you say in the bottom tank is it on thei side of the radiator? I see no wires coming from the bottom. Which side would it be on? I see the drain plug.
Expert:  Ted Ritter replied 11 months ago.

It would be facing the engine. Let me see if I can find a picture and get back to you'

Customer: replied 11 months ago.
Ok sounds good I am standing by. I can see the lower coolant hose, drain plug. This is a 2004 model with a 4cyl
Expert:  Ted Ritter replied 11 months ago.

I have to check my wiring diagram and get back to you the 04 4 cylinder may not have a separate switch for the fans, let me check.

Customer: replied 11 months ago.
Ok
Expert:  Ted Ritter replied 11 months ago.

There is no separate temp switch for the fan, it's controlled by the engine temp sender and the engine control computer, the temp sender you replaced did it have two wires on it, a black and a pink one? did you also check fuses related to this circuit? 40A cds, 10A ecu ig, 40A RDI?

Customer: replied 11 months ago.
the engine temp sensor is what I replaced. The fuses are fine. When I remove the 2 wires from the engine temp switch the fans both come on full speed. The check engine light came on the dash. Plug it back up and the fans go off. Temp gauge still rises to the same location when running.
Expert:  Ted Ritter replied 11 months ago.

Yes that's too high, Was the check engine light on before replacing those parts?

Customer: replied 11 months ago.
No it wasn't. But the fans would not kick on to help cool down. That's when I replaced the engine coolant sensor. Both heat and AC work fine. No leaks of coolant
Expert:  Ted Ritter replied 11 months ago.

Ok, it could be one of those relays there are three, I have a diagram and I'm going to see if I can come up with something that may isolate this a little better maybe a relay is not functioning, possibly fan relay #1 which is turned on by the others when the a/c is on but won't when a/c is off, this will take a little time and I will get back to you a little later and see if I can make some sense of this.

Customer: replied 11 months ago.
Ok. Here is a picture. Fan relay one is baby blue one. I have swapped it out with one of the others next to it. Fan relay #2 is brown. Fan #3 is baby blue
Customer: replied 11 months ago.
Here it is
Expert:  Ted Ritter replied 11 months ago.

Let me think about this a little and get back to you.

Customer: replied 11 months ago.
Ok thanks
Expert:  Ted Ritter replied 11 months ago.
7838-428a-8810-f4bde063d1ed_img014.jpg
Customer: replied 11 months ago.
What do you think?
Expert:  Ted Ritter replied 11 months ago.

Here is a link o the wiring diagram of the cooling fan

Pull the #3 relay out, turn the key on, ground the #2 terminal of the #1 relay, this should cause the fan to run.

Customer: replied 11 months ago.
Ok. When you say ground should I hook a wire to the terminal then to negative lead on the battery?
Expert:  Ted Ritter replied 11 months ago.

Try to ground it with the relay in, then to any metal part on the engine, make up a piece of wire to use.

Customer: replied 11 months ago.
Ok doing it now
Expert:  Ted Ritter replied 11 months ago.

OK/

Customer: replied 11 months ago.
I got nothing. Image below..
Customer: replied 11 months ago.
Fan did not kick on when I removed relay #3 and hooked a wire to terminal #2 of relay 1 with the key to on.
Expert:  Ted Ritter replied 11 months ago.

Do you have power to terminals 1 and 3 with the key on?

Customer: replied 11 months ago.
I'm not sure. I don't have a special meter or anything.
Expert:  Ted Ritter replied 11 months ago.

A 12 volt test light will work you can pick one up at most hardware stores or auroparts places, I think home depot has them too,

Customer: replied 11 months ago.
Ok. If there isn't any power coming in what do you think?
Expert:  Ted Ritter replied 11 months ago.

Power comes from the 40A RDI fuse which is always hot and the 15A ecu ig fuse which is hot only with the key on, we have to start checking these voltages and go from there.

Customer: replied 11 months ago.
Ok. I will have to pick up a meter when I'm out. May be tomorrow or Monday before I can get back to it. Will you respond to the emails then?
Expert:  Ted Ritter replied 11 months ago.

yes, I will be here most of the weekend.

Customer: replied 10 months ago.
Hey Ted,Are you Avail? I picked up a volt meter.
Expert:  Ted Ritter replied 10 months ago.

Yes, I'm online, I'll get back in a few minutes.

Expert:  Ted Ritter replied 10 months ago.

I had to re read everything and look at the diagram, anyway, with the key on there should be voltage to the terminals 1 and 3 of the #1 relay socket, you can pull the relay out to measure this

Customer: replied 10 months ago.
Ok. Should I hook wires to it and plug the relay in and test it?
Expert:  Ted Ritter replied 10 months ago.

To test this voltage remove the relay, tun the key on, connect the negative wire from the meter to ground, make sure the meter is at the 20 volt setting, touch the red positive wire from the meter to each terminal in the fuse box where the relay was, must be 12 volts to the 1 and 2 terminal per the diagram

Customer: replied 10 months ago.
Ok. Hey Ted I have one that has a negative lead with a lead that lights up when there is current. Will that work or it has to register the amount?
Expert:  Ted Ritter replied 10 months ago.

It will work, if there is 12 volts it will light up.

Customer: replied 10 months ago.
Ok doing it now
Customer: replied 10 months ago.
Ted! When I grounded and tested terminal 1 & 3 no light
Expert:  Ted Ritter replied 10 months ago.

Ok, let's make sure the light is working, connect it to ground then tough the positive battery post, does it light up?

Customer: replied 10 months ago.
Oh wait hol on a sec. There is a fuse I have to put in the tester
Expert:  Ted Ritter replied 10 months ago.

Ok verify it via the battery test first.

Customer: replied 10 months ago.
Ok. No light
Expert:  Ted Ritter replied 10 months ago.

Can you send me a picture of what you are using?

Customer: replied 10 months ago.
Ted I'm ashamed. Bought it at Walmart for $2.88. Walking in the auto store now to grab another
Expert:  Ted Ritter replied 10 months ago.

Just tell them you want ta 12 volt test light, I'm going to be offline for about an hour.

Expert:  Ted Ritter replied 10 months ago.

check the voltages at the relay and let me know.

Customer: replied 10 months ago.
Ok when I touch terminal 1 the light comes on. When I touch terminal 3 the right fan kicks on
Expert:  Ted Ritter replied 10 months ago.

Thanks , remove the #2 relay and check this again, all I need to know now if two of the terminals have voltage and then let me know which ones do referring back to this picture.

Customer: replied 10 months ago.
Ok about to now
Customer: replied 10 months ago.
Ok on fan #2 relay terminals are different. When I place it on 1 it clicks. When I place it on another it lights up. On the other it does nothing. This is with the key on.
Customer: replied 10 months ago.
The terminal to the far left has power. The terminal to the far right just clicks. The one in the middle does nothing
Expert:  Ted Ritter replied 10 months ago.

Ok, it sounds like you grounding another relay, let me see if I can send you a diagram os the fuse box sockets so we are sure to be checking the correct terminals.

Customer: replied 10 months ago.
Ok
Expert:  Ted Ritter replied 10 months ago.

t82912b42-d445-43ac-b15b-d632888dfec5_img020.jpg

Make sure you are checking the fan relay #1, with the key on

terminals 1 and 3 have to have 12 volts.

Customer: replied 10 months ago.
Ok on Fan #1 we have light on this terminal.
Customer: replied 10 months ago.
We also have light on this terminal.
Expert:  Ted Ritter replied 10 months ago.

Ok, in the last picture is there also voltage at the terminal one space over?

Customer: replied 10 months ago.
No. That one does not light up and it makes a clicking noise.
Expert:  Ted Ritter replied 10 months ago.

Are you sure you are on the #1 relay? Does it match up with the diagram in the fuse box in relation to the other relay at the end, the larger one?

Customer: replied 10 months ago.
This is Fan #1 according to the car diagram on the fuse box. It's the blue one unplugged next to the head relay. Here is the pic.
Customer: replied 10 months ago.
Fan #2 is bigger and it's brown. See pic below
Customer: replied 10 months ago.
Here is fan #3 relay. It is blue. See pic below
Expert:  Ted Ritter replied 10 months ago.

Ok, remove the other two fan relays for now, check voltage again on #1 which two have voltage?

Customer: replied 10 months ago.
Ok all three relays are removed. Key is on. I have power on Fan Relay #1 here.. (See pic)
Customer: replied 10 months ago.
here..(see pic)
Expert:  Ted Ritter replied 10 months ago.

Both pictures are the same

Customer: replied 10 months ago.
Sorry. Check this one.
Expert:  Ted Ritter replied 10 months ago.

I don't understand this, that terminal should not have voltage, if it has the fan should run without the relay in, not sure what is the problem right now, there is an identical relay, can you check it and see if it shows the same results?

Customer: replied 10 months ago.
This is the C/OPN relay next to the #1Fan and it lights up the same way as Fan #1 Relay when the key is turned.
Expert:  Ted Ritter replied 10 months ago.

The picture you sent on 3:07 remove the light, connect the ground clip to the terminal that had voltage, the one at a time touch each of the other terminals, which one causes the light to turn on?

Customer: replied 10 months ago.
Fan #2. The left fan kicks on when in this terminal.
Customer: replied 10 months ago.
Light on this terminal.
Expert:  Ted Ritter replied 10 months ago.

Try a new relay in spot #1

Customer: replied 10 months ago.
Ok. Just swapped out the horn relay and put it in fan relay #1 spot. I put the light on fan relay 2 and it does the same thing. Fan comes on and the other side lights up
Expert:  Ted Ritter replied 10 months ago.

I have to go offline for today, so I'm going to opt out at this time and perhaps anther expert can come up with a solution to this later today or tomorrow, sorry but I'm just not able to help with this after all.

Customer: replied 10 months ago.
Ok. Will the new mechanic see everything we have talked about? Thanks
Expert:  Joshua Haynes replied 10 months ago.
Hi my name is ***** ***** I will assist you
Customer: replied 10 months ago.
Hey Josh. Great to E-Meet u. Are you able to see the previous conversation between Ted & I?
Expert:  Joshua Haynes replied 10 months ago.
I will read over the comments between you and the other technician and we will come up with an answer buddy, it seems like you have a fun one on your hands!
Customer: replied 10 months ago.
2 days and still nothing! It has been a treat.
Expert:  Joshua Haynes replied 10 months ago.

Hi, so I have read through your comments with the other mechanic and I want to make sure we are not getting off topic before we need to...I need to know first what your primary goal is on this car: to find out why the fans aren't working or to find out why the car overheated. I also need to know if when you drive it on the highway will it still overheat? If you run it with the sensor unplugged would it overheat? this would tell me if the fans are the problem or not. If so, we can get into the wiring of the fans. Let me know what info you have and we'll move forward!

Customer: replied 10 months ago.
Hey Josh. I purchased the vehicle for my son. I noticed while driving it that the temp gauge went up 3/4 the way (see pic). I popped the hood and noticed that the fans were not kicking on. After a lil research I decided to replace the engine sensor as well as new Toyota coolant. After this the temp gauge still rises to the same spot after the car runs a while. My goal is to fix the overheating. From what I understand the fan plays an important roll in keeping the engine cool.
Customer: replied 10 months ago.
Temp gauge
Customer: replied 10 months ago.
I will have to run it with the sensor unplugged to see if it over heats. When I unplug the sensor the fans both come on as well as the check engine light. I have not taken it on the highway because of the overheating.
Expert:  Joshua Haynes replied 10 months ago.

great, thanks so much for the insight. You are absolutely correct that the fans play an important role in keeping the engine cool...it is responsible for dissipating the heat from the radiator while the car is not moving or there is an excessive temperature condition. But, when I hear that the car is only going 3/4 of the way up, this is an indication of a combustion leak. this can cause an excessive amount of air in the system and cause the temperature gauge not to read correctly. In any event, I would like to know if it overheats when sitting still for 15 minutes and the fans stuck "on". If it still overheats, this is indicative of a much more serious problem. It sounds like you can reproduce the fans on condition by simply turning on the air conditioning if I remember right. This would be the best way to verify the fans are the cause of the overheat, because it would allow you to keep the temperature gauge working so you can be able to tell if it is overheating or not

Customer: replied 10 months ago.
let the car run and turn on the AC so both fans run?
Expert:  Joshua Haynes replied 10 months ago.

Exactly!

Customer: replied 10 months ago.
Ok going to start it now and turn on the AC. Question... What would keep the fan from coming on even if it was a combustion leak?
Customer: replied 10 months ago.
Ok it's running. AC is on. Both fans spinning
Customer: replied 10 months ago.
Ok ran 15 mins temp in the same place with AC on with both fans turning
Customer: replied 10 months ago.
Hey Josh. So do you think there is a head gasket problem?
Expert:  Joshua Haynes replied 10 months ago.
It really sounds to me like your head gasket is blown. A solid indication of a head gasket leak is the cooling system running at 3/4. You can get a carbon dioxide tester at a parts store like Auto zone and verify the head gasket issue. It is a blue liquid that will turn to yellow or green in the presence of carbon dioxide (which is only present when there is a head leak) At that point the fans are only a secondary issue.