1999 Toyota Camry 2.2 Coolant fan isn't coming on.

Check relay first

Unplug the fan and run a jumper wire from the battery to it. If it comes on, you know the fan is good. If fan is good, replace the relay. If that doesn't seem to work, replace the temp sensor.

Easy to fix take the wire off the switch location is on the the onstage housing upper hose.one wire switch take unplug and ground it on engine while key is on position if the fan come on the switch is bad if nothing happens the relay is bad or if it stays on the relay is bad Two fan one ac fan on when ac is on engine fan is run buy switch

Jon, just a tip, pay attention to the date of the post you are responding to. It's over a year old. You are just wasting your time. Go to "All questions" and answer the new posts. People have long since fixed the issue by now. Not trying to be a snot, just letting you know since you are a new guru.....

Actually, I know several people that will look through older questions because they are having the same issue. That's what I am currently doing as I'm trying to troubleshoot a fan issue. Thanks, Jon. I appreciate you still giving input even thought the asker may not need it. These cars are still on the road and other people have similar issues.

Minga... first of all, there's a tremendous amount of mis-information in this posting, from start to finish. Beware of what you read. Not everyone that posts stuff online is a mechanic or knows how to properly diagnose a problem. Problem: Fan(s) not turning on while car is sitting, running at idle. Engine eventually overheats. I have personal experience with this problem. I am a professional mechanic. My experience with a 2001 Camry 2.2L 4 cylinder engine was that the fan switch, located in the bottom tank of my radiator was malfunctioning / bad. Also the weather pack connector that attached to it was corroded and needed to be replaced. Because of this, the radiator fans would only turn on when commanded by A/C circuit (defrost circuit) and at no other time, as that is a separate control circuit designed to run both fans when additional cooling is needed for A/C use. Normally, only the PRIMARY fan runs when necessary, dictated by engine temps that begin to get excessive (somewhere around 200 degrees F - I didn't measure the actual "on" temp specifically). The primary fan is located on the left side (diriver's side) of the car. It is switched by the fan temp switch that is located & screwed into the bottom of the radiator, below the secondary fan, located on the right (passenger's side) of the radiator. You must first remove the secondary fan to gain easy access to the fan switch. If you disconnect the fan temp switch when the car is running (or ignition switch key on, engine off), the primary fan will run non-stop. This is because the fan temp switch keeps the fan off until the switch warms up and opens the circuit. It is the exact opposite of how many circuits are designed. In other words, if you put a paper clip (jumper) in the two female pins of the disconnected sensor plug connector, the fan will shut off. The fan switch is in a terrible location, as it is susceptible to corrosion and problems due to the elements (moisture, winter rock salt and calcium, for example), and is a common failure point. Again, also check the connector/wiring, as it can often be an issue as well. *** Some very important things to note... The SENSOR located / threaded into the cylinder head near the top radiator hose is for the EFI management of the engine. Nothing else. It does NOT control the cooling fans. The one-wire sender to the left of that sensor controls the coolant temperature gauge in the dash, NOTHING ELSE. Good luck folks, and god bless! ~ AJ

Thank you turbodieseldude I was searching for an answer to the issue you addressed and you are right I seen a tremendous amount of misinformation on the internet until I came to your post. Thank you it solved my problem and made it very simple.

Turbo diesel dude....Thank you...Thank you....Thank you....Turns out I have the exact same issue. My daughter would complain that her 99 Camry 2.2 would overheat at idle in traffic when it was hot with the window down. But would be normal running temperature with the a/c on. I checked and replaced every relay. Checked the fans. Then replaced them. Still the same problem. It never made sense till I read this and checked. Sure enough that was it. I cannot Thank you enough. A $25 dollar part that no one could explain, I mean no one. Also a problem that now doesn’t make sense to me. Cost me in parts over a thousand. I’m mean I replaced water pump. I mean I could not figure it out. Never thought of it having two ways to turn a fan on. Still makes no sense to me. Again Thank you.

I really can’t blame other people’s posts. This is the type of issue that you must know the issues with this car. The design is great but sometimes it is a little overdone. But they have been great cars. I have had 5 camrys and will keep buying them. They all run 300000 miles plus. If you maintain them. 4 or 6. I presently have an 07 camry 6 cyl. Great power. With only 265000 miles. Runs great. Love the power. I keep the engine oil clean and the coolant fresh.

TurboDieselDude Re: Cooling Fan Switch for Toyota. Hey TDD, your comment helped me determine the subject switch was defective (although it had been replaced about 2 weeks ago. Pulled the plug and the fan came on, so I got it exchanged. Same symptom with the new switch. Engine steams but fan does not come on. It's as if the switch is not getting hot. Found out my son poured some radiator sealant in recently. Could that stuff have stopped up the radiator such that the sensor never contacts the hot coolant? Temps at thermostat, engine block, and top hose all read the same with a laser thermometer. Is there a run of defective switches? Should I disconnect the top hose and check for flow? Any thoughts?

TurboDieselDude Thanks, that was my question, the sensor is normally closed and opens when hot.. Most of them are the opposite . I tested the sensor in boiling water and it remained closed.

Ninemil : Yes, there ARE most definitely some "brand new" defective fan switches out there. How to easily test your car's fan switch: With a multimeter (continuity/ohms meter), check the fan switch's continuity between the 2 terminals. It should have continuity between the two terminals at normal outside ambient air temperature. The "normally closed" circuit is what keeps the fan turned off. Now, heat up some water on your stove. With the water near boiling, place the sensing end of the sensor into the hot water. Probably best to use a pair of pliers, to protect your hands. With your multimeter's test leads already connected to the switch terminals, the meter should show no continuity between the two terminals. In other words the circuit is now "open", when sensor is placed in the nearly boiling water. The open circuit is what allows the radiator fan to turn on. I would recommend testing any brand new fan switch before installing it. I purchased three different brands of switches before I got one that reliably functioned properly. Apparently quality- control is basically non-existent in today's parts marketplace?! The failures were rather interesting & frustrating, to say the least. The original OEM fan switch had failed closed. Thus, the radiator cooling fan remained off. The first brand new aftermarket fan switch I purchased online from a Chinese retailer. The price was almost too good to be true, and I should have probably known better. But, since money doesn't grow on trees , & this was my own vehicle, I took the risk. To my dismay, the new Chinese replacement switch failed right out of the box, in the exact same manner as the bad OEM switch. Grrrr! The second brand new fan switch I purchased failed in the exact opposite manner. After 2 mere drive cycles of using my car, (to & from work, one day) the fan ran non-stop whenever the ignition switch was on. I actually discovered the problem the following day, when I turned the key on and I heard the fan roaring before I even started the engine. I thought to myself, "Why the hell is that fan running? I hadn't driven the car anywhere yet, and it was still cold." Grrrrrrr! The third brand new switch that I purchased, worked properly, and several years later, it still does. As I recall, the good quality switch was a Borg Warner branded switch that I purchased from my local AutoZone. It was substantially more expensive than the previous two that I had purchased. Again, the first one came from the internet for dirt cheap. The 2nd crap switch was the cheapest one I could get from the local parts store. So, the number 3 costly aftermarket replacement fan switch was the charm. Now, I'm definitely not saying that spending top dollar is the answer, but in this particular situation, it definitely was the answer. Good luck folks!