Fixing an overheat condition (the radiator fan) on a 1997 Toyota Corolla/Geo Prizm

This is a video I made showing how I helped my friend Bryan fix the overheat condition his car was having. Most aspects of a car's cooling system are the same from vehicle to vehicle, so this fix may very likely help even if you have a different vehicle.
I also talked about how the cooling system in your car should work, and some other parts that may fail and cause a problem.
If you have annotations disabled, please enable them for this video. There are a few points that I needed to clarify after the fact.
Like I said in the video, feel free to ask questions in the comments. I will try and answer them as soon as I can.

[@jamesyarbrough4777]

thanks for the video. i was racking my brain trying to figure out how the single wire fan switch worked.

[@CoolAce1]

Among the best diagnostic videos I've seen. I had a Prizm years ago. It was not the clone that the Nova/Corolla was in the 80's. I had some issues with the Prizm that the corolla did not share such as defective a/c vents, and a leaky window. Radio was better in the prizm than corolla. Other differences existed too.

[@dominichadley2712]

I honestly love how this video is like a Combination of Scotty Kilmer & Technology Connections! :D

[@jhavajoe3792]

Just a Thanks! I was ready to install new thermostat. Saw your video and decided to recheck fuse to fan relay. At the top of the fuse, it was visible the tiny wire was blown as in video- 1:49.

[@aliabtahi2313]

first duck tape fuse cover from inside, or glue it . then the rest was all very informative and at the end providing the summary/recap of everything indicates he knows of one of best teaching methods

[@tharozlosangeles1385]

Wow that was probably the most thorough, helpful, and well narrated/explained diy video I've ever seen! Thanks man - I'm guna try all those tests and I'm sure one of them is guna fix my fan problem.

[@MartinVSpartan]

I’m telling you right now its the temp sensor cuz I’ve checked all but my Corolla came with a cut pigtail and or bad sensor so I’m going to get the pig tail but ether way if that doesn’t work then it’s the sensor as I’ve done everything else expect those 2.

[@dominiqueritchey6795]

Good job, man. You are helping this girl diagnose what part to replace quickly. Thank you

[@shortybb]

I know this voice… it’s the dude from TECHNOLOGY CONNECTIONS!! Humble beginnings, still humble though 😌

[@KingofGeo]

I am not a motor head and i was able to understand your video, great job! All instructional videos should be like this.

[@HLucas-yd4ru]

A well put together vid explaning the Toyota cooling sys electric circuit. I'm having prob with fan on 92 Tercel and this has put me on the right track to fix the fan issue. Keep up the good work ... and thanks

[@Codybutty]

man your so help fullyou just help me keep my job I new what it was but for got the simple fix now I don't have to worry about over heating thank you man

[@nathanielgoolaman4125]

Excellent step by step video with simple explanation. Thank you.

[@carlomango407]

Thank you. Your explanation is simple and easy to understand

[@talons100]

Great job explaining the issue, 5 Star video thanks for your help

[@MartinVSpartan]

I just want to say that it really did help. Thank you. It makes sense and it is a great design once I understood how it works on how you explained it. Thank you

[@makgobamafokoane272]

Well, this video has assisted me in diagnosing my 1996 Corolla (South African), found the issue to be the Relay. I replaced it, and the fan is working. 19/11/2023 🔥🔥🔥

[@botella7771]

awesome, you are an expert explaining technical issues

[@Grantjr1]

Excellent tutorial, well made and to the point. Thanks!

[@lexxx196913]

I was having the same problem wit my Toyota corolla just wanted to say thxs ur video was very helpful and thxs to ur video I found out what I needed to fix the sensor was not working. Thxs for ur help. Alex

[@wildcat1897]

Thank you Alec.Excellent instructor.

[@The_Macaroon]

This worked for my Toyota Corolla Verso. Thank you so much.

[@MarvinTheMarshun23]

This video is easy to understand and very helpful ! Thank you very much !!

[@dirkz.149]

I can tell you are an expert in what you are doing although I could not follow everything you said. Thanks

[@pistonring1399]

This video is very helpful and informative. Searching for video to replace my corolla 1995 thermostat and just chanced into your video, I learned a lot from it. thanks....

[@slaminbody]

Alec, you are amazing, thank you soo much for your help.

[@DanielLopez-sr8kg]

Very helpful this video I have a 1996 camry is doing that I'm going to due that tomorrow I purchase that car yesterday so thanks very much for your video and sharing you knowledge

[@oshane2012]

youre a life saver man thank you: I have a 1999 Toyota Sprinter Sedan

[@seymoarsalvage]

I been working on cars for 30 years now, mostly Japanese. For a non-car guy, you nailed this!

[@Poppadee78]

Just wanted to say thank you for posting this video. Purchased a pretty sweet 1997 Toyota Corolla CE with 177k for $700 so naturally I thought I struck gold. After a 25 minute drive home I realized that the fan wasn’t working. Came across your video and sure enough, ife is good again. Thanks again man.

[@kolsidify]

These really helped me a lot. Thanks Alec

[@pierobotteri6646]

Came back to comment and say thank you, fixed my car bc of this a few months ago. I live in Miami, so it's okay to leave my connector off HAHA

[@chalanan]

Awesome video, thank you for posting it. it helped me fix my overheating problem.

[@POgsDar23]

i wish u were my automotive instructor.crystal clear explanation.easy to understand..=)

[@kbruin79]

Thank you for the detailed explanation. 9 years later and your video is still rocking KZbin. Big thumbs up.

[@Louis-pp8zg]

Very nice job to explain this problem. Thanks a lot.

[@rustammaziar4371]

Great job Man👍 It was really really really helpful.

[@Smalltechguy]

Great video on trouble shooting. My relay done the exact same thing as your had done. I also replaced with a new temp sensor and I still get nothing. I've been pondering this issue for quite a long time. I'm getting close though... Ive got a 2000 toyota solara which is basically the same...

[@ellisbloomfield1467]

Absolutely amazing video!

[@stevebuscemi4970]

Great, thorough vid. Thanks for the explanation

[@homeschoolingandawareness]

Well done. Great troubleshooting skills.

[@milkmanpeter]

I got to say that your a very good teacher I am mechanic but you explain it great

[@luisdejesus5131]

Good Job, Very Helpful and to the point.. Thank You..

[@trayfenodonnell5386]

Great video. Well explained. Thanks!

[@tony123456789fuck]

Top man must have lots of mech experience. Thanks very very good

[@gskvllofficial3511]

This video was really helpful for me today!

[@apollozcreedAV]

Excellent video...thanks for sharing

[@raafatmoftah1746]

I like the video... smart & professional... thanks...👏👍

[@guesswhomartin9249]

Wow.... Thank you ... You gave the best explanation I've ever heard. This video is SOLID GOLD. Ok... one question for you. I should go back and listen to your video again, but my question is; When the engine cooling sensor is still in my hand, Is this a normally open sensor ? or normally closed sensor ? Thank you again, Have a great day.

[@nunaokai4402]

Guess that it is open when its in your hand. Cos the fan is turned on only when its closed ( usually at high temp)

[@ChaosBeforeOrder]

this is exactly what i was looking for thanks.

[@2509498788]

That was very informative for me. My 96 corolla fans arnt kicking on. I will use this info to correct this problem. Thanks. Very well narrated.

[@fargeeks]

mine still overheats during summer highway driving and I just had 10w 30 put in and fresh antifreeze and water put in but I believe it's 60/40 instead of 50/50 and fans work but I think it takes a slightly longer time to cool down any ideas?

[@williamdowell7646]

fargeeks bad thermostat

[@fargeeks]

+William Dowell actually no it turned out it was the radiator and or the water pump which I had both replaced

[@2509498788]

William Dowell no it was the sensor.. when I disconnected it the fan turns on.. this video helped me fix it.. I still have the car.. it's parked .I've migrated to a 93 Camry

[@williamdowell7646]

Usually the water pump will start making a rack or leaking before it fails, radiator could've been dirty.

[@ToyotaPaseo]

Fantastic video! Should work for other Toyotas of the same generation as well.

[@normanbell236]

Great explanation, thanks Alex

[@kylemac8672]

Very helpful video, helped troubleshoot the problem I was having. Liked & sub'd

[@annasfetkou5007]

Great video, thank you for sharing. I have exactly the same car, with an overheating problem. In my case, when disconnecting the cooling temperature sensor and turning the ignition on, the fan does NOT run. I checked the fan's operation with a paper clip and it works just fine. I also checked the reley, and it works just fine, too. Do you have any idea what should I check next? (My mind goes to possibly worn cables, which keep the reley grounded all the time, not allowing it to de-energise.)

[@mikecarmona_bakulaw]

Great video Sir!

[@teror1sta]

My problem was fan didn't turn OFF . Problem was connector in Fuse Box !! Good tutorial !

[@mengledoe]

Which connector?

[@marekatshopo1743]

Good day Simple and easy to understand. Thanks a lot

[@aromas5]

Alec..ur a good instructor ..u explain things very well.. i have only one query.. the reason maybe why fan did not run when you'v connected the sensor is because the engine is still in its cool state. . it will only de-energize the relay coil when the engine reached a predetermined high temp when engine is running.. causing the temp-operated fan to run.. & yes i also do believe that the culprit is the temp sensor.. since uv temporarily fixed ur friend's car.

[@daunclestone3825]

very informative video. thx!!!

[@justsannie_2050]

Thank you...very helpful!

[@a.tillman2498]

Very Nice Job .....Thank You!!

[@CitizenZ9823]

hey Alec great video I have a 1999 corolla with what appears to be developing the same problem I followed your tuition and it was like I was working on your friends red corolla. The only question I have is how did you disconnect that plug from the sensor? Mine is stuck fast

[@NezukoZ31]

thank you for the video! turns out i know my project car a lot better than i do my corolla haha

[@rwegasila]

Thanx it helpfully i manage to solve my car overheating problem

[@tony123456789fuck]

Peter PR How did you do it

[@waynefisher4585]

Great narrate, this is whats wrong with my 1997 Toyota Corolla

[@k-automotivesolutions5941]

Great video! Very helpful to me 👍👍👌🙏🙏🙏

[@yasiryaqub]

Hi Alec, Thanks you very much for the video. It's really help full for me. I need your assistance regarding radiator issue. When my car heated up, all the water goes out in bottle and also bottle cap open with the radiator pressure. one thing more my radiator fan also not working. My car model is Toyota 98 sedan.

[@ihabphelobos7455]

Thanks for your video it was awesome

[@drrogerbrowne]

Great presentation! I have a Toyota Corolla 1999 and I notice there is a sensor on the engine block just below the intake manifold that is shattered. Which sensor is this?

[@slowvag8v]

Excelent video!

[@soktheaseng6974]

And awesome video by the way!!

[@raygateinvestments6988]

Hie thanks for the video it was very help full. i have a Toyota Raum, i removed the thermostat but the did run the fun come on letter when is boiling. so what cloud be the problem?

[@jasper86able]

also will that be ok if i run it with the switch disconnect continuously as it make the fan run

[@MrLaChien]

Hi I think you may have just saved me at least $300 I have replaced every relay o the vehicle as I had already replaced the water temperature sensor after it failed but I had purchased a Tridon aftermarket part. Your advice to disconnect the sensor line and turn on ignition proved the high speed fan is operating so now just the line to the sensor or the aftermarket sensor is a dud. Thanks again.

[@raulalderete3323]

the fans in my 1997 Honda Odyssey not work and the thing is that when I turn on the car, the temp. gauge goes all the way to have even that I know that the car is cold, and I can`t find the problem, cu`s I all ready change the thermostat, the cooling temp. switch, the cooling temp. sensor, and I test the relays by switching them and the fuses, so what else you think I need to do?

[@MCCENTx2]

What stops the fan from turning on when the car is off? Edit: It's a 15a fuse under the left kick panel that enables the fan. '95 Geo Prizm

[@chrizizdaman]

Thanks for the video! If this censor is bad will it set a code in the ECM and the check engine light come on? I believe this is my problem I also found out that I can turn the AC on and it would turn the fan on and cool the car back down when it was over heating.

[@lytourlor9447]

My car is 1994. I think that the second fan does not working, the one on the left side of the radiator. The first fan works fine. I feel that it is hotter in the engine compartment of car because I see water evaporated from the engine hood while drying in rain. Which relay should I check? Thanks

[@MrGW2fanboy]

Hi Alec thank you for the very informative video I have subbed. I have the same problem and tried what you did but the radiator fans still wont turn on when they should (at 90 celsius), I have a Toyota Previa 2000 (ACR30) and here is what I've tried so far: -Radiator fans work fine -Radiator Fan Temperature switch works (tested outside) -Coolant temperature sensor works (tested outside) -All fan relays work (tested outside) and all fuses are fine -When ignition is ON a paperclip into connector for the fan temperature switch turns the fans on -The paperclip trick you did at 5:43 doesn't work for fan relay 2 and 3, but works for relay 1 -When the fan temp. switch connector is unplugged with ignition ON, the fans don't turn on Could this mean the fan relays aren't getting power and there's a problem with the wiring going into relay box? Or should power NOT be going to those relays until the fan temp. switch triggers at 90 celsius? I apologise it is a bit of a read, I'm really clueless at this point, thank you for your time in reading this I would really appreciate any help.

[@petercini6953]

Hi I have the same car but 99 model, I have shorted the relay and the fan came on ok,than I tried taken the sensor clip off but the fan stayed off,can you please let me know what that means and what to do after this...... Thank you

[@johnmaz8744]

Hey Claude and Alec, I think your highway problem is probably the thermostat!!!!!!...or maybe you have a leak somewhere..hose..radiator..or water pump (when the seal in water pump breaks, it will drip out a little hole on the bottom of the water pump)...also, Alec...excellent job on the video!!!!!!...My only advice would be the water pump issue..some guy once said that it always works (if it is spinning, it is working, because it is simply an impeller) [of course the impeller could snap off internally**rare, I'm guessing**]...he told my that the only real problem with the water pump is when the seal breaks and it will leak...but will always work if belt-connected!...Also, I believe the water flow usually flows from the radiator out the top to and through the thermostat housing...and I saw some other post where a guy took his radiator cap off and could see that there was no flow???!!!--I don't know for sure...but it makes some sense! Thanks again...very useful information from everybody and especially you, Alec!!!!!!

[@johnmaz8744]

A former Army mechanic at AutoZone told me RockAuto is great for online parts! www.rockauto.com/catalog/catalog.php

[@leor.salazar4521]

I understood your explanation. However, my 97 Camry has two fans! They would both come on until I replaced the radiator. What do you think happened?

[@nyne3141]

Respect man u help a lot

[@orlandomaldonado3706]

Gracias por su excelente explicación.

[@sandrarobertson2446]

YOU ARE FABULOUS!!! KNOWLEDGABLE, THOROUGAL and PATIENT~~~ I HAVE A 96 GEO Prism, that has a slow water drip at the "bottom" left of the radiator,(looking from under the hood, with your back to the windshield. eg., Your face is facing the front of the vehicle, while looking from under/inside the hood.) I can't tell if the slow drip is from a hose, or the radiator. NOTE: In addition, the engine stays cool/normal temp when in the freeway, but over heats at stop and go traffic, the problem in your 97 GEO Video, soooo, it appears as though I now have TWO PROBLEMS... P.S., What is the name of the part (Fan" you are going to replace) and the part number? Are you going to replace it with "genuine" parts, or are you ordering after market..., on Ebay or from the Dealer??? Lots of questions, I know, but I don't have the funds to send it to the repair shop, and I like the challenge of repairing things myself. YOUR RESPONSE IS GREATLY APPRECIATED, SANDRA LEE

[@mosconioni4523]

Great video tutorial, I have a 99 Toyota Rav 4 which is a similar engine as above, but in my test my radiator fans will not come on unless I remove the radiator fan switch which is located near the lower radiator hose. The problem is even after replacing the radiator fan switch it still doesn't kick on the fans at higher temperature. I'm guessing the theory is invalid that if you unplug a sensor and the fan doesn't come on that it would be faulty. Please help

[@MYB079]

This video was helpful. However, my car does not overheat just in traffic. in fact, it overheats after i have been running for a little while. Then, the engine shuts off. After a cooling off period, it will start again and I can continue to my destination. Do you think replacing the thermostat will fix this? Or could it be as serious as the water pump?

[@alex298dos]

thanks, for long time, I was trying to figure out what was the problem in my corolla 93 ... thanks for this excellent video, I repair my car and save me money

[@futbolero4152]

Hi there cool video and very imformative and maybe I can get some help here. My 01 accents fan wont turn on either. Checked relay, and fuses good, tested fan, good. However when I unplug my radiator tmp sensor, the fan doesnt run. I checked the volatge on plug to the fan and its fine. When I checked the voltage to plug to sensor. Gave me a weak signal but shoulndt it turn on regardless if its off? I know engines since I could walk but never been too good with electrical wiring systems. Any info is greatly appreciated

[@DMichaelReese1953]

Alec...If you have a car that overheats even with a belt driven fan and it has an auxillary fan also..is it wise to just run a bypass switch when in slow traffic to turn on aux. fan then..?

[@superpooper_2030]

My car Vios when engine ignited, the coolant fan did not turn on. When i on the air conditioner, the fan will start spinning but off and on within few seconds interval repeatedly. The air conditioner will not cold after car running for 20min. What is the problem?

[@albertorguevara4454]

This is a gr8 video

[@davidlegasi4080]

Hello, a very nice video I have the same problem I just leave the thermoswitcht unplugged so that the fan will run. I already replaced the thermoswitch, and when I plug it and wait for the temperature to go up it does activate the fan. what could be the problem? please help my car is 2E corolla.

[@Ahmed.Mallah]

Excellent video By Mr. Alec, I have same issue, I have Mitsubishi Nativa 3 Liter, I remove thermostat but my call heating indication showing half always which was before setting. I was check by mechanic he replace relay i pay bill approx: 250$ last summer, but now problem again. Kindly can you tell me what i have to do because here once go to Mechanic every one giving own idea to make money.

[@khyberafridijamrud]

It means when the coolant temperature sensor is closed it will energise the relay where the fan contact is open . And when the coolant temperature sensor get heat will open the circuit and will cut the relay . And when relay cuts so the relay will pass contact to fan . Correct me if I am wrong

[@dma654]

When I unplug the ECT sensor the fan should automatically turn on right?

[@stephaniewarren2357]

you are a good man alec. I got the sensor unplugged fan runs now. would you say I'd need to replace the sensor as soon as possible to avoid the fan burning out?

[@FTW_Wolf]

im having this problem with my 97 elantra wagon. i have checked my relays they are good but even with the cable of the sensor the fan does not turn on. my book says i have to get my ecu (car computer checked) at my local hyundai dealer. i am going to replace my sensor first before i get the ecu looked at. it is a much cheaper alternative. and its only 40 bucks to try so go for it.

[@jasper86able]

man you are awesome but i have one question i got Hyundai Accent and i got exactly the same issue if the direct it the fan runs and if the connect the connector which turns on the sensor fan does not work now i most of the Indian mechanics are saying its a problem with ECM in the car is that correct do i have to replace it or can it be fixed because ECM costs a lot

[@Sandiforty]

Very helpful.

[@mckoylach1622]

I have a 96 Corolla,I replaced a thermostat,a radiator but still overheated,is the water pump the last one,to be the cause of overheating ?