Toyota Repair Problems? Ask a Mechanic for Answers ASAP
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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.
It would be facing the engine. Let me see if I can find a picture and get back to you'
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.
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?
Yes that's too high, Was the check engine light on before replacing those parts?
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.
Let me think about this a little and get back to you.
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.
Try to ground it with the relay in, then to any metal part on the engine, make up a piece of wire to use.
Do you have power to terminals 1 and 3 with the key on?
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,
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.
yes, I will be here most of the weekend.
Yes, I'm online, I'll get back in a few minutes.
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
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
It will work, if there is 12 volts it will light up.
Ok, let's make sure the light is working, connect it to ground then tough the positive battery post, does it light up?
Ok verify it via the battery test first.
Can you send me a picture of what you are using?
Just tell them you want ta 12 volt test light, I'm going to be offline for about an hour.
check the voltages at the relay and let me know.
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.
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.
Make sure you are checking the fan relay #1, with the key on
terminals 1 and 3 have to have 12 volts.
Ok, in the last picture is there also voltage at the terminal one space over?
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?
Ok, remove the other two fan relays for now, check voltage again on #1 which two have voltage?
Both pictures are the same
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?
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?
Try a new relay in spot #1
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.
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!
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