Toyota Repair Problems? Ask a Mechanic for Answers ASAP
This wire schematic for the system is a bit complex do you have a copy of the wiring diagram? Do you have any test equipment such as a volt meter or a 12 V test light? I do not believe in replacing parts I believe in diagnosing. This can be a bit tricky on this type of problem in this kind of format. I can give you some checks and tests are run. Let me know how you would like to proceed. I will be monitoring on and off most of the evening and I can get back to you with some more information. There may or may not be a quick fix but I do not replace parts to find the fix.
Yes it does help. Here is how the system is supposed to work when the coolant reaches a predetermined temperature temperature sensor in the bottom of the radiator causes the fans to run in a series circuit and run at half speed or slow speed. If the air conditioning is turned on and the high side pressure reaches a predetermined amount of fans kick in to parallel circuits and run on high. This is the short version but to make all this happen there is a lot of relays and switching that has to take place. Did you get the temperature sensor in the bottom of the radiator installed correctly and made sure that the female pins in the connector are not corroded? With the key on if you disconnect the connector in the bottom of the radiator to the temperature sensor do the fans come on?
Oddly with the key on ...but the engine not running... the fans do not turn on at all... they are off.... does that answer your question also? or do i need to try and pull the connector to the sensor at the bottom of the radiator.... it is very difficult to get apart and then back together with the radiator in place... =(
I need to know if the electrical connector when disconnected from the sensor at the bottom of the radiator causes the fans to come on. This should be fairly easy to reach on the four-cylinder engine. Simply press the lock tab and pull out on the connector. Just be mindful that the fans should come on and don't have your other hand in the fan. Turn the key on and see if the fans turn on. Make sure that the fuses in the fuse box under the hood (30 amp RDI and 30 amp CDS are good and have 12 volts.
yes.... once i disconnected the connector...with just the ignition on...the fans are on. Do i still need to check the fuses, since the fans turned on?
No. You need to check the sensor and make sure it is not staying closed all the time. If you put a jumper wire across the pins of the connector the fans shut off correct? It is designed to open the contact points inside the sensor above about 189 degrees to turn the fans on. Test the continuity of the sensor cold it should have continuity above about 189 to 195 degrees it should open and have no continuity. If you leave the connector disconnected will the coolant circulate and the engine stay in the normal coolant temp range?
Yes, with the jumper in place the fans do stop. Yes if I leave the connector un plugged then the fans stay on and the temperature stays right where it should be without any change. If I go and get a new sensor have we solved the problem? I thought about replacing it when i had the radiator out, so that cost is fine.
Ideally I would like to see you test the sensor by getting it hot and making sure that it is not opening but based on the fact that the coolant in the radiator started to get hot and boil over, provided it was circulating and there was no air pocket causing it to overheat, the sensor more than likely will solve the problem. Are you 100% certain that the coolant was circulating in the thermostat was opened when it started to overheat. If this is the case then the temperature should have been well above 190° and the switch/sensor should've opened allowing the cooling fans to come on. When you replace the sensor make sure that your oring fits smoothly inside the radiator plastic housing I usually like to wrap the threads with a little Teflon tape just for insurance purposes.
Thank you the new sensor seems to have done the trick and everything works fine. How do you get your payment for the information?
I got paid when you clicked on the accept button if you choose to leave leave a bonus that would be greatly appreciated its kind of like a tip at a restaurant. I'm glad you're able to get it going.