1997/Thunderbird/V8. If the electric radiator fan comes on when engine is cold started, is this a bad sensor & where is it located?


Asked by Dec 03, 2011 at 10:04 PM about the 1997 Ford Thunderbird LX

Question type: Maintenance & Repair

radiator fan sensor. Where is it & how do you test it?

28 Answers

this is normal ,it is the low speed kicking.if the sensor was bad it would not come on at all.nothing to be concerned about.

4 of 4 people found this helpful.

Papa, I appreciate the help but this is not normal. The fan should not come on when engine is cold. I've had this car since brand new & the fan never came on when cold starting. Also, the starter is good. Will you please send me an email so we can talk direct. I will call you if you include your phone number.

2 of 2 people found this helpful.

I forgot to include my direct email. Please write to me at "talktoschmidty@yahoo.com". I really need to talk to someone "live" on the phone. I have tried everything with my car & this is the only thing I found that will get the motor. Honestly, I've checked MAF, MAP, Fuel pump, Pressure at the rail, everything around the intake, Throttle body, Injectors, I've cleaned & degreased motor, etc. The only way this car will start is by turning the key on & waiting for the fan to stop. This takes about 3 minutes.

2 of 2 people found this helpful.

I'm still hoping for someone who knows the answer. I now think it's the engine coolant sensor and need to know how to test it. I pulled it out and it reads about 35K. In boiling water, about 5k. So it is working but I don't know why the fan is on for the first 3 minutes and must go off before ithe car starts. The range is the problem. Like, at what temp should it turn the fan on or off? Any body know about this?

1 of 1 people found this helpful.

I have 3 T-Bird supercoupes,checked on all when key switch is turned on,fans run on low speed,so this is normal,did some research,asked a few questions,problem sounds like the key switch is the main problem,coolant sensor has nothing to do with it,all it does is tell the gaduge the temp of collant.when motor warms up.

2 of 2 people found this helpful.

Thanks again Papa for taking the time to help and responding. I don't know the years or engine sizes of your 3 SC's, but on my 1997 4.6(V8) there are 2 sensors in the plastic intake. There is one on the passenger side that is the sending unit to the gauge(verified by removing plug and observing gauge). The one on the driver's side uses the 5v signal (reference wire) from the computer. I've now taken the ECT sensor out to test in my house. According to a Voltage/Resistance/Temp chart that someone emailed to me, my 37K (across the two pins)at room temperature is normal. Now, I plan to test by placing the sensor in a pan of water on the stove. It should read about 58K at 50 degrees, 16K at 104, 2k at 212, 1.18 at 248, etc. I hope to find the temp that triggers the fan to go on to see if my sensor is defective. Whether it is a "low speed" fan setting as all 3 of your cars have, my car still will not start until that fan stops. And again, my fan never came on at cold start before since I bought the car new. That is, until the "Check Engine Light" came on this summer and it started running bad(idling high, no acceleration, & that feeling like it's only running on 6 or 7 cylinders). And I really don't understand why a temperature controlled electrical fan should come on when the engine is cold. (it is 20 degrees right now in Wisconsin). I know that the sensor is only about $20. but I really can't afford it & it's never a good idea to just keep throwing parts at a problem and hoping it works. Especially electrical parts that can't be returned once installed. However, I do very much appreciate that you took the time to review my dilemna AGAIN and took the time to write me. I don't want you to think that I don't appreciate your advise but I just can't believe it's the ignition switch, low speed fan theory, etc.

mine are 2-89,s 1-90.not being rude,but what you saying dont make sence,I been ASE ford certified for 37 years,I know theses cars and what you saying is not the problem.try a DIS modgul,the gray box on top of ac compressor,temp sensors is not your problem,youre wasting your time fooling with them,its electral,bad key switch or DSI as mentioned.im just trying to help you fix your car,it seams like you are stuck on sensors and are not open to other options.

2 of 2 people found this helpful.

one more option,pull the fan relays from fuse box under hood,see if it cranks up,if it dos,the relay is burnt out.now im out of ideas,at least try this,let me know how it goes.

2 of 2 people found this helpful.

Hey Papa. Well, I can't find the DIS but I will keep searching. Per your suggestion, I pulled the 2 relays in the (under the hood)fuse block on the driver's side. I don't know if these are the ones you meant, but they had no effect. That is, the motor did not fire. But the electric fan did not stop either so perhaps these are not the fan relays. I finally tried the new ECT sensor & and you were correct, it did not solve my problem. However, as I'm still trying to find my problem since this past summer, I has to try. Also, today I had the codes read again & it is still coming up with all 3 O2 sensors & the ECT sensor. However, it did not flag a code for the MAP, MAF, & IAC. As always, thank you for your help. And I will post my results, if I ever find the solution. I wish I could afford to just take it to the Ford dealer but I can't. And I really want to know what is doing this as opposed to what the dealership charges me for and tells me it was.

the DIS is a gray square box with several wires on a plugin.dont sound like the right relays,the fans will not run with the right ones pulled out,no power to them.the 02,s is not the problem eather.recheck the fuse box again for the relays.if you look inside the cover,it showes the ones you need to pull.also look in fuse box under dash,see if their is a fuse for them,same thing inside cover it will show which fuse is to what,they are numbered,while in this fuse box & the other,check for any blown fuses.we will get to the problem.also at starter,check the fusable link,at where the wires hook to starter,is a wire running through a round solid plastic with wire comeing out other end,pull on it easy,if the wire streaches.that is blown,if so,just cut off at each end,any auto parts store sells themstrip & tie wires together.new one will have a 35 amp fuse in it.

1 of 1 people found this helpful.

i have a 97 thunderbird with the v6 engine. it runs really rough when it first starts. it doesnt stall but almost. coult the coolant sensor be my problem as well?


I never resolved this problem because my 97 bird blew a serpentine belt outside of Madison, WI. & by the time I got to an exit and under the overpass it had already cooked. Now, I don't know if it warped the head or simply blew the gasket, as it has become a lawn ornament until I have more time to piss around with it. I will rejoin this thread when I get back at it.


I purchased my 97 thunderbird in March. At the time I bought it... the fans were kicking on and I would have to wait 3-5 minutes for them to kick off before it would start...... Now, the fans will NOT kick off so I unplugged it under the hood to see if my car would start then but NOPE because the fuel pump was running as well and we just hadnt been aware of that... We have replaced so many parts such as fuel pump and filter, fan relay switch, brain,and several sensors..........still though my car will not start!!! HELP please!

5 of 5 people found this helpful.

Missi, and others, I never got my car running since the overheating problem discussed previously, however, I may get back to it in the next few weeks. My latest info I can offer is 1). Look for a bad(like rusty or missing)ground wire. As I ran my car off the road into a field, I may have pulled a wire right off, or you could have an old rusty connection. Remove the wire, clean end and surface area and re-attach. And 2). There is a grey box behind the passenger headlight known as the CCM. I believe it stands for "constant control module". Anyway, someone told me this could be the problem too. Although I haven't verified this yet, new they cost around $180. or so. I priced one at a salvage yard and they wanted $80. I am going to check for bad grounds though before I replace the CCM. I will come back to this thread in a few weeks when I get back at it.

1 of 1 people found this helpful.

i have a 97 thunderbird V6 3.8L my fan will not come on it will come on randomly when i hit bumps or drive on the eway can someone help its really cold in Michigan right now.

1 of 1 people found this helpful.

The eternal ongoing blog here. I just finished three weeks of fairly intensive diagnostics related to most of these symptoms. first off, no guarantee to anyone. Regarding having to count to 10 which I did before it would fire, first thing to check is your fuel pump pressure to see if it is holding around 30lbs when you turn on the keyl. That was one of my problems, the pump in the tank was leaking pressure back into the tank. I had already replaced a bunch of stuff and never thought about the pump being part of the problem since it was less than 6 months old. Only comment about this I would make is don't buy the cheapest priced parts because they most likely are cheap and won't last long, if at all. The problem for the delayed starting is most likely your PCM or brain. The bad news is that they run anywhere from 110 bucks for the base brain which are pre-programmed at the factory and are usually in stock, at least they were at Autozone where I got mine. There is a more expensive one available for those more heavily optioned cars like mine that runs 150 bucks and you have to send in your VIN number and approximate mileage so it can be specifically programmed to match your car features. EITHER WAY YOU HAVE TO PULL OUT THE OLD BRAIN TO GET THE MODEL NUMBER TO DETERMINE THE PROPER ONE TO ORDER. I would say have fun with that exercise but it isn't much fun and that would be cruel. Ok, that answers the hard starting question, at least what worked for me. As far as the fans go, they are designed to come on low speed whenever the temperature gets above a certain point and stop when it drops below a certain point. Turning on the AC will turn on the high speed circuit which is ok if you live in the South or hot regions where it is on most times anyway but that is not a real fix. If it were me, I would replace the temperature sensors first and if that does not work and assuming your PCM(the brain is good), I would replace the CCRM second. It is located on the inside of the radiator cradle just in front of the air filter box which you have to remove to get to it. You may be able to find a good one at the junk yard llbut if not they are over a hundred also. Still beats car payments though. Papa has some good advice regarding the key switch also, but I have not had opportunity to look through that aspect as yet. My low fan will not come on like it is supposed to so tomorrow I am replacing the sensors. If that is the problem, I did it all backwards since I already sprung for the CCRM relay box and that did not totally fix the problem. Curious question to Fivefli, if it's cold why the need for the fan anyway. Can you turn on the AC and turn up the temp to warm, the high speed fan override should make the fan go and it will blow warm air on AC mode as well. Carl in Florida.

1 of 1 people found this helpful.

PS. Send me an email and I will send you the 301 page owners manual and the engine sensors location schematic to help you in your frustration, er uh I mean adventure. I love old cars, give me a car with just a carb and i am in my element, but these injected modern marvels are gonna be the death of me.



Most interesting. In a nutshell, I have been chasing this same issue of "no start" while the fans run. I fully believe that the PCM (brains) are not functioning, and until the PCM is functioning you will NOT be able to start the car. Here is why I say this... While the fans are running, you cannot communicate with the PCM with any form of a code reader. Once the fans quit, you can. The CCRM (constant control relay module) will default to the fan running in the lower speed mode UNLESS it is turned off by the PCM. This can only happen if the PCM is functioning correctly. So I am inclined to think that the PCM is the culprit to these issues. I will try to post more if I can locate another PCM to try. Note: The CCRM has been changed, the fuel pressure is correct. Once the car starts, it runs fine. It is temperature sensitive - the colder it is outside, the longer the fan runs before you can start the car.

1 of 1 people found this helpful.

Hey there 97Owner, I had forgotten about this ;post. You hit the nail on the head regarding the CCRM switch.Ford could have done a better job of sep[arating the relays rather then packaging the way they did. My CCRM tuned out to be good, it wqw not getting a signal from the brain. I went to our local auto parts outlet after locating one (AutoZone) that offered pre-programmed units based on your VIN. I installed the new brain (another item they could have locaed somewhere more conveniently, and turned on the key. the fans were quiet and the bird fired right. Since that experience, the car has performed flawleslsly with the exception of a failed intake manifold which I replaced. I have to admiot that after doing the intake, I feel much more comfortable dealing with intelligent systems like these great 4.6 engines. I went out this past week and purchased another low miles bird, so now I have two. The new one has 39,000 on it and has a rate SPORT package on it, sun roof, turbo style wheels up[graded suspension SC ground effect package, all wrapped up around the 4.6 drive train. These are great cars and people are beginning to buy them up Keeping both of mine until I don't drive anymore. Thanks for the feedback and confirmation of what I was experiencing, Replacing the brain is a good call if your ccrm is good.


I wanted to follow up on the issue of the hard start issue I mentioned about a month ago. The resolution was the PCM. For whatever reason, it was not booting up (they are computers by the way), and was not turning the fans off, or doing the other chores needed to start the T-Bird. I went to NAPA and ordered a rebuilt PCM providing them with the Year, Engine, VIN, AND the calibration code listed on the driver's door jam. With both of those, you will get the CORRECT PCM for your application. And, yes, they are somewhat of a chore to remove, but I did it within a half hour, and had the new one installed in about 15 minutes or so. It fired right up, and ran perfectly. The car was driven another 30+ miles to return the core with several stops and starts, and started perfectly every time. If you have to remove the PCM, here are some tips: First, disconnect the NEGATIVE lead off of the battery and insulate or restrain it so it cannot accidentally reconnect itself. You will most likely burn up the PCM if you disconnect or reconnect it with power applied. Remove the glove box lid - it takes removal of three screws along it's hinge. Remove the kick panel cover on the passenger side - it is clipped in place, and uses two plastic fasteners with ribs on them. Remove the AC/heater fan control box (this is the box with heatsink that is located just below the fan motor and connected to the fan with a heavy red and heavy black wire - the connectors are easy to disconnect - just study them and be gentle. Disconnect the green, and grey or black harness connectors below the PCM - this is necessary to help gain additional access and clearance to work. Loosen the single bolt holding the PCM connector to the PCM - it is easy to remove with a socket. Reach up and carefully remove the foam backed black plastic sound deadener panel between the PCM and the AC fan box - you have to study what way to slide it out from between the PCM and the AC fan box. Remember how you removed it, as you will have to reinstall it later. There is ONE small bolt in the PCM retaining bracket (white plastic clamp / retainer) that needs to be removed - it is on the lower corner away from the firewall. I dropped the bolt down inside the body and had to retrieve it with a magnet - so you are so warned. Gently lift the lower corner of the PCM retainer plastic away from the PCM and slide the PCM down and towards the firewall. I removed the PCM from the glove box opening, not from the bottom. Note how you do it, and install the new/rebuilt one the same way. Carefully reinstall everything you removed and disconnected. Pay attention to ALL connectors and make sure you reconnect them correctly and double check everything. I accomplished this all with a simple set of tools that I carry with my car in the trunk. I hope this helps someone.

2 of 2 people found this helpful.

To anybody who knows about 97 Tbird w/3.8.... Just checked my fuses under the hood n now my car won't start. Any advice??


fuel pump is not coming on fuel switch is working brand new pump still is not coming on


On a 92 Thunderbird just put a commission module working before but now my car acts like its not trying to get no power


Ignition module is not getting any power Turn key lights keep flickering on and off




Issue was resolved. replaced the brain and no more problem.

1 of 1 people found this helpful.

Thank you all. Although I have not tried it yet, because of the expense, I am convinced that the "brain" PCM, computer, or whatever, is behind the problem. I will spring for the replacement and hopefully see the same glorious sound of the fan stopping and the bird firing up. I hope to follow up soon.

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