Cooling fans not working!!! Bad ECT Sensor?? - Honda-Tech
Go Back   Honda-Tech > Honda and Acura Model-Specific Technical Forums > Honda Accord (1990 - 2002)
Log In 
Search



Cooling fans not working!!! Bad ECT Sensor??

Reply
 
 
 
 
LinkBack Thread Tools Search this Thread
Old 07-06-2011, 03:16 PM   #1
Trial User
 
Join Date: Jul 2011
Posts: 2
iTrader Rating: (0)
Default Cooling fans not working!!! Bad ECT Sensor??

I have a 1998 accord LX 4 cylinder. I have noticed that neither cooling fans will engage. I changed the thermostat thinking that was the problem and that didnt work. i tried jumping the fan switch on the thermostat housing and they still did not come on. i have been researching to find a solution to this problem with no success. i cant run the ac without the fans because it begins to boil over the radiator overflow tank. i have read something about the engine coolant temperature sensor being bad would maybe cause the fans to also not work properly. where is that located and how do i check to see if the sensor is bad? any info would be greatly appreciated.
lexanthon is offline   Reply With Quote
Old 07-06-2011, 04:48 PM   #2
Honda-Tech Member
 
GhostAccord's Avatar
 
Join Date: Mar 2007
Location: East Coast 506, Canada
Posts: 10,143
iTrader Rating: (0)
Send a message via MSN to GhostAccord
Default Re: Cooling fans not working!!! Bad ECT Sensor??

It could be the coolant temperature switch, or it could be the fan relay or fan control module.

The fan switch, is located in the thermostat housing. To test it you need to check it's resistance. As the temperature of the coolant goes up the resistance between the two contacts should go down.

If you pick up a Haynes manual it will have all of the testing procedures for the above mentioned components. I have the manual here, unfortunately I don't have the time to type out all of the steps for each component.
GhostAccord is offline   Reply With Quote
Old 07-06-2011, 06:16 PM   #3
Honda-Tech Member
 
nus_dogg's Avatar
 
Join Date: Oct 2008
Location: St. Paul, MN
Posts: 3,695
iTrader Rating: (0)
Default Re: Cooling fans not working!!! Bad ECT Sensor??

It can't be a bad ECT; otherwise, you'll have a hell of a time getting your car started as the ECU will be seeing -40 from the ECT and be dumping hella fuel to get it to start.
__________________
1994 Honda Accord EX - JDM H22A
- 204whp/157wtq
Quote:
Originally Posted by toycar View Post
Breaking the bank, maybe. Feeling like a boss, likely.
nus_dogg is offline   Reply With Quote
Old 07-06-2011, 08:42 PM   #4
Honda-Tech Member
 
sublime423's Avatar
 
Join Date: Apr 2004
Location: NORTH TEXAS
Posts: 107
iTrader Rating: (0)
Default Re: Cooling fans not working!!! Bad ECT Sensor??

First off lets "keep it simple, stupid!" before you go doing all these checks let's look at the simple checks first. So, both fans don't work? will they come on with the A/C turned on? If yes, you got a bad fan switch, if no you got two bad fan motors. Now let me back up what I am talking about with another quick check. lets say you turn the ignition on (key on engine off) A/C off as well the fans should be off. Disconnect the fan switch which is on top of the thermostat housing it is a two pin connector take a thin and I mean thin paper clip and make a "U" and make the two terminals touch (you don't need to JAM the paper clip into the terminals just touch them together)....this is "jumping" the switch. If the fans come on that will back up the bad switch theory and if they dont I'm saying fans. One more check then I'm out. Plug the fan switch back in and start the engine turn the A/C on. No fans.....take a something and smack the fan motor like a screwdriver or small hammer a couple of times (you are not trying to knock it out the park, just knocking on a door strength) sometimes this can jar a bad fan motor in to working for a short time. If they come back on you must realize that they still need to be replaced. Ok some can say fuses and relays and PCMs and waternators. checking all fuses is not a bad idea but the fact is the fans are ran off different fuses and relays to keep one fuse or relay from shutting down both fans at the same time. If you do all this and want to be for sure here is one last check if you have a Test light, disconnect the fans with the key on engine off and check for power to each fan if you got power check for ground if those check out you got bad fan motors.


I hope this helps.
__________________
Just because you put a red valve cover on your buddy's Integra one time and you change your own oil does not make you a Honda/Acura specialist.
sublime423 is offline   Reply With Quote
Old 07-06-2011, 08:54 PM   #5
Honda-Tech Member
 
sublime423's Avatar
 
Join Date: Apr 2004
Location: NORTH TEXAS
Posts: 107
iTrader Rating: (0)
Default Re: Cooling fans not working!!! Bad ECT Sensor??

Quote:
Originally Posted by lexanthon View Post
I have a 1998 accord LX 4 cylinder. I have noticed that neither cooling fans will engage. I changed the thermostat thinking that was the problem and that didnt work. i tried jumping the fan switch on the thermostat housing and they still did not come on. i have been researching to find a solution to this problem with no success. i cant run the ac without the fans because it begins to boil over the radiator overflow tank. i have read something about the engine coolant temperature sensor being bad would maybe cause the fans to also not work properly. where is that located and how do i check to see if the sensor is bad? any info would be greatly appreciated.
Oops.....Missed that part lol!

bad ECT sensor= check engine light on. BTW the ECT sensor has no control over the fans.
__________________
Just because you put a red valve cover on your buddy's Integra one time and you change your own oil does not make you a Honda/Acura specialist.
sublime423 is offline   Reply With Quote
Old 07-08-2011, 05:42 PM   #6
Honda-Tech Member
 
Join Date: May 2010
Location: Youngsville NC
Posts: 1,256
iTrader Rating: (0)
Default Re: Cooling fans not working!!! Bad ECT Sensor??

ok, this is a few days old, been on holiday so trying to catch up.

Wouldn't the first thing be to put 12v to the motors and be sure they are good? The OP jumped the switch. Either one (a or b) should make the fans run, as long as IF it was thermo a the key was "on".

"sublime"- you might have had that somewhere in that blob of text, I got lost after the first line or two.
__________________
66 Chevelle...78 F150...89 LXI 5 Speed
...97 SE auto...01 Sabb SE...07 Pilot 2wd...16 Pilot Touring AWD
poorman212 is offline   Reply With Quote
Old 07-12-2011, 12:09 PM   #7
Trial User
 
Join Date: Jul 2011
Posts: 2
iTrader Rating: (0)
Default Re: Cooling fans not working!!! Bad ECT Sensor??

thanks for all the advice!!! i jumped the fan motors to the battery and fans didnt start. i put a meter to see if they were getting power and they were. so what i did was hit the motors with a hammer and they finally engaged. i was shocked when they began to spin. ordered new motors today, but will get me through the week with ac again. thanks again!!!
lexanthon is offline   Reply With Quote
Old 08-01-2011, 11:39 PM   #8
Trial User
 
Join Date: Aug 2011
Posts: 10
iTrader Rating: (0)
Default Re: Cooling fans not working!!! Bad ECT Sensor??

I'm glad that I saw this today... I'm having a similiar problem.. My ac compressor, compressor fan and coolant fan won't come on.. I've jumped the fans and the ac compressor.. All of them work when I jump then.. So I ruled out the fans or compressor not working.. Since the window relay and the coolant relay are the same i swapped them.. And the windows still worked So i've ruled out the relay.. I checked the fuse in the car just as a precaution before I posted.. and still Nothing.. I don't understand wtf is going on.. And they all stopped working at the same time.. what is common in these to make this happen

*update* jumped that thermo/fan switch.. NADA .. I need help!

Last edited by T Wgproductions; 08-02-2011 at 12:01 AM.
T Wgproductions is offline   Reply With Quote
Old 08-02-2011, 04:40 PM   #9
Honda-Tech Member
 
Join Date: May 2010
Location: Youngsville NC
Posts: 1,256
iTrader Rating: (0)
Default Re: Cooling fans not working!!! Bad ECT Sensor??

TW- What year is this? 4 or 6 cyl?

Which underhood fuse have you checked?
__________________
66 Chevelle...78 F150...89 LXI 5 Speed
...97 SE auto...01 Sabb SE...07 Pilot 2wd...16 Pilot Touring AWD
poorman212 is offline   Reply With Quote
Old 06-21-2012, 06:02 AM   #10
Honda-Tech Member
 
Join Date: May 2012
Location: Macon Ga
Posts: 12
iTrader Rating: (0)
Default Re: Cooling fans not working!!! Bad ECT Sensor??

ChrisB from Macon Ga here. I'm going to check an issue I'm having on a 96 and running hot. I changed the themostat. I've bleed the air very well. I turn on the car and start the ac. Only the left side fan turns on. My inf readings are 158-175.front and back..may not be getting it hot enough to turn the other fan on??
__________________
Chris Brooks - Macon Ga.
ChrisMaconGa is offline   Reply With Quote
Old 06-22-2012, 03:57 AM   #11
Honda-Tech Member
 
DrJimmieRustles's Avatar
 
Join Date: Jun 2012
Posts: 5
iTrader Rating: (0)
Default Re: Cooling fans not working!!! Bad ECT Sensor??

Have you tried jumping the fan to ensure the motor is good?
DrJimmieRustles is offline   Reply With Quote
Old 07-30-2015, 03:31 AM   #12
Honda-Tech Member
 
Join Date: Feb 2010
Posts: 349
iTrader Rating: (0)
Default Re: Cooling fans not working!!! Bad ECT Sensor??

I know I'm bumping a way old thread but I'm having a problem just like the final two posts outlined here.

When I turn on my a/c only my driver side fan comes on. The cooling fan stays off. When I jump the cooling fan from the thermostat-mounted ect switch, it works. When I jump it from the underhood relay, it works. So why doesn't it come on with the a/c or actually ever? I of course have a new thermostat, bled it well, etc. But I can't remember the last time that fan came on.. and it's been 100 here the last couple days. The car isn't overheating at all though.

I tried jumping it from the block-mounted ect sensor but I do believe that sensor does not control the fan anyways.

There's great info here in this thread but I'm not breaking it down right in my mind I think.
backinblue92 is offline   Reply With Quote
Old 07-30-2015, 06:45 PM   #13
Honda-Tech Member
 
Join Date: Feb 2010
Posts: 349
iTrader Rating: (0)
Default Re: Cooling fans not working!!! Bad ECT Sensor??

Well it turns out the cooling fan does come on with the a/c. So why does it not turn on otherwise? Does jumping the switch when the engine is over 195* mean the switch isn't working properly?
backinblue92 is offline   Reply With Quote
Old 07-30-2015, 07:26 PM   #14
Honda-Tech Member
 
Join Date: Dec 2008
Posts: 8,118
iTrader Rating: (0)
Default Re: Cooling fans not working!!! Bad ECT Sensor??

I really am totally lost as to when it comes on and when it doesn't come on. If I had to take a guess, I would say you're trying to jump the thermoswitch b, which only turns on the radiator fan after the ignition is off.

Again, I'm not too sure what the issue is 'though.
holmesnmanny is offline   Reply With Quote
Old 07-30-2015, 10:23 PM   #15
Honda-Tech Member
 
Join Date: Feb 2010
Posts: 349
iTrader Rating: (0)
Default Re: Cooling fans not working!!! Bad ECT Sensor??

Sorry about that, I was up super early this am and hadn't had my am coffee yet. So I wasn't completely clear.

I assume the accord to be set up just like the prelude and found this thread in a search so I thought it was worth throwing it out there.

After some testing today, my cooling fan doesn't come on unless the a/c is on, during which both fans come on. Independently, the cooling fan isn't turning on. First I jumped the relay, and it came on. Then I jumped the coolant fan temp switch (the plug at the thermostat housing) and heard the relay click and the fan came on again. So I know the relay is good, fan motor, wiring. Thermostat housing is grounded as well.

But I'm trying to nail down why the fan isn't coming on when engine temp passes it's threshold, I believe 195*. I imagine that when I turn on the a/c it closes the circuit on the relay and therefore bypasses the coolant fan temp switch altogether? So that would indicate that it is that temp fan switch malfunctioning?

(I should have left the coolant temp sensor out of my post in the first place, as that has nothing to do with the fan- though it could be a reason my engine is running rich)
backinblue92 is offline   Reply With Quote
Old 07-30-2015, 10:34 PM   #16
Honda-Tech Member
 
Join Date: Dec 2008
Posts: 8,118
iTrader Rating: (0)
Default Re: Cooling fans not working!!! Bad ECT Sensor??

Are you aware that both fans are cooling fans ? I'm not sure why you keep alluding to a "cooling fan". They are both cooling fans. I still have no idea which fan it is that isn't working.

I'm going to spell it out for you, the passenger fan is the radiator fan. Since you have ac, the driver side fan is the condenser fan.

You could have used either passenger fan, driver side fan, condenser fan, or radiator fan and that would point to which fan you were talking to, but instead somehow you managed to just say "cooling fan".

The more I see your posts, the more I feel like you're just trolling here.
holmesnmanny is offline   Reply With Quote
Old 07-30-2015, 10:37 PM   #17
Honda-Tech Member
 
Join Date: Dec 2008
Posts: 8,118
iTrader Rating: (0)
Default Re: Cooling fans not working!!! Bad ECT Sensor??

WATER PUMP - SENSOR for 1998 Honda ACCORD SEDAN

This is a diagram of your cooling system sensors. You can use that to describe just exactly which sensor you are testing.
holmesnmanny is offline   Reply With Quote
Old 07-30-2015, 11:53 PM   #18
Honda-Tech Member
 
Join Date: Feb 2010
Posts: 349
iTrader Rating: (0)
Default Re: Cooling fans not working!!! Bad ECT Sensor??

I apologize for being more specific than "pass side fan".

Cooling fan = radiator fan = pass side fan
A/c fan = a/c condenser fan = driver side fan

I've never heard the radiator fan referred to as anything other than the cooling fan, as the driverside fan only engages with a/c.

I'm trying to pinpoint why the radiator fan, aka cooling fan, is not functioning except when a/c is on. When a/c is not on, it does not engage at any point. It does not ever stay on after the car is turned off, nor does it ever engage when the car is running. I jumped the thermo switch, number #15 in your diagram, to check that the entire controlled side of the system was working. It is. So I'm trying to ascertain why the controller side of the system (aka thermo switch) isn't activating the fan when temp goes above its degree threshold.

For what it's worth, the car has never overheated and never goes above normal temp. But that doesn't necessarily mean the fan is working properly.
backinblue92 is offline   Reply With Quote
 
 
 
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
1991 honda accord ex cooling fan not turning on junior91hondaac Honda Accord (1990 - 2002) 11 10-27-2014 12:03 PM
94 civic ex cooling fan problem bernard_s3 Honda Civic / Del Sol (1992 - 2000) 2 03-11-2011 04:45 AM
Cooling Fan not turning on properly hmtcrxsir Honda Civic / Del Sol (1992 - 2000) 4 04-29-2009 06:48 PM
Cooling Fan prob 1FastCoupe Honda Civic / Del Sol (1992 - 2000) 0 04-11-2005 09:08 PM
Cooling fan problems - please help HX_Guy Acura Integra 4 05-31-2002 08:38 AM


Tags
1996, 94, ac, accord, coming, cooling, dont, fan, fans, honda, jump, odyssey, radiator, realays, whats, work

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



 
All times are GMT -8. The time now is 07:25 AM.


2014 Copyright, InternetBrands Inc.
Powered by vBulletin® Version 3.8.7 AC2
Copyright ©2000 - 2015, Jelsoft Enterprises Ltd.

Honda and the Honda marquee are registered trademarks of the American Honda Motor Company, Inc. Neither American Honda Motor Company nor its subsidiaries or affiliates shall bear any responsibility for Honda-Tech.com content, comments, or advertising. Honda-Tech.com is not affiliated with American Honda Motor Company in any way. American Honda Motor Company does not sponsor, support, or endorse Honda-Tech.com in any way. Copyright/trademark/sales mark infringements are not intended or implied.