91 Accord: radiator fan keeps running after car is off....then, dead battery.
 

Guys,

The problem started a few weeks ago when I realized that the radiator fan wasn't running at all. Turns out the fan relay was bad. Since I couldn't find one in a local store, I replaced the bad relay with the "power window relay."

Now the radiator fan doesn't stop running when the car is off, which kills the battery.
I went out of town on Thursday and came back yesterday. Then I got in the car and the battery was dead. I recharged it (well AAA did) and it died again today.

Any thoughts?

I read that sometimes the relay sticks??

Thank you so much!


Modified by mcalvelloxx at 7:18 PM 8/21/2008

Re: 91 Accord: radiator fan keeps running after car is off....then, dead battery. (mcalvelloxx)
 

Problem: The fan runs continuously (longer than 19-minutes) when the key is removed. The symptom is a dead battery. The fan turns off only when the ignition is turn off then on. 99% chance the fan timer is bad. Usually happens to the 90-93 Accords.

Solution: The reasonable solution is a replacement of the timer control unit. Before a replacement it would be wise to troubleshoot. When the fan does not turn off after 15 minutes swap the cooling fan relays in the engine fuse compartment with another identical relay. If the fan refuses to turn off replace the fan timer unit.

Replacement: Remove the access panel on the driver's kick panel and search for a box way in there the size of two cigarette packs with 8-terminals. The 86-89 Accord fan timer unit is located under the passenger seat. Unbolt the unit and swap it with a new one.

Re: 91 Accord: radiator fan keeps running after car is off....then, dead battery. (BLKFLSH)
 

I would not run out and buy a new fan timer control unit without FIRST testing the temp switch at the top radiator hose outlet.
That Temp Switch is in fact THE MOST COMMON CAUSE of your problem.

Re: 91 Accord: radiator fan keeps running after car is off....then, dead battery. (Mr Yamada)
 

After it runs have you ever managed to catch it? https://honda-tech.com/forums/images...s/emsmileo.gif

Re: 91 Accord: radiator fan keeps running after car is off....then, dead battery. (Mr Yamada)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mr Yamada &raquo;</TD></TR><TR><TD CLASS="quote">I would not run out and buy a new fan timer control unit without FIRST testing the temp switch at the top radiator hose outlet.
That Temp Switch is in fact THE MOST COMMON CAUSE of your problem.</TD></TR></TABLE>

I'm having the same problem. Would you happen to have a picture of the switch?

Re: 91 Accord: radiator fan keeps running after car is off....then, dead battery. (LCDeuce)
 

Pretty sure he's talking about the green switch in this picture where the upper radiator hose meets the head.

http://cow.pasture.com/~bix/DSCF0001.sized.jpg

Re: 91 Accord: radiator fan keeps running after car is off....then, dead battery. (waciii)
 

Nice first post. https://honda-tech.com/forums/images/smilies/emthup.gif Thanks.

I hope this is not too dumb a question… how do you test that switch? Thanks.

Re: 91 Accord: radiator fan keeps running after car is off....then, dead battery.
 

Search, my friend, is your friend:)

from: https://honda-tech.com/forums/honda-accord-1990-2002-2/radiator-fan-wont-come-help-3151153/

I've found lots of info in the stickies and FAQ, or by entering terms I'm searching for in the forums search bar....

....or plugging this into google: "item you're searching for" site:honda-tech.com

If you find that the switches are good (FYI, I believe there's two that regulate fan function, one on the inlet hose and the other on the outlet), than you should look at the fan timer.

Have a look at this thread on CB7tuner that talks about both fan switches as well as the fan timer (with photos): http://www.cb7tuner.com/vbb/showthread.php?t=199393

Re: 91 Accord: radiator fan keeps running after car is off....then, dead battery.
 

The only thing about this is that even if that switch is bad the fan timer should stop the fan from running after 10 minutes. Since the battery is running down it would appear that the switch can not by itself cause the battery to run down. This issue should be more likely be the timer.

I understand this thread is old, i'm just giving this advice for the next guy.

Re: 91 Accord: radiator fan keeps running after car is off....then, dead battery.
 

Quick question Holmes: just so that I'm clear, does the fan timer switch (or is it supposed to switch:) the fan off independently of any temperature switches? I.e. independent on info from any sensors, it should switch the fan off? And that time is around 10 min?

Thanks!

Re: 91 Accord: radiator fan keeps running after car is off....then, dead battery.
 

Not quite sure I'm following the question. If therm B is above set temp (~224 I think) then ground is sent to the timer. The timer will allow the fan to run for up to ~20 minutes or until thermo b drops below ~224.

http://techauto.awardspace.com/overheating.html - more reading here.

https://honda-tech.com/forums/showth...ht=cooling+fan - or here as well

Re: 91 Accord: radiator fan keeps running after car is off....then, dead battery.
 

What I got from Holmes's response was that regardless of the signal from the sensor, the timer would shut off automatically after 10 min (time superseding temp).

But what I'm getting from your response is that it's either/or time (20min) or temp (thermo b < 224), and if both criteria are not satisfied than the fan will stay on, which means that the fan could stay on indefinitely if the thermo b switch is bad.

One of the links you provided seems to support that:

"After the key is removed and the engine cold and by plugging the high temperature thermoswitch back in and the fan runs then the high temperature thermoswitch is bad. (error in this section is spotted by a honda-tech.com member)"

Bottom line, and before I make this too complicated: I just want to know if the timer is the supreme ruler of keeping the fan running indefinitely (>20 min), or if the thermo sensor can also have a hand in this condition if it is faulty.

Thanks!

Re: 91 Accord: radiator fan keeps running after car is off....then, dead battery.
 

The way I think of it, the only purpose the timer has is to stop the fan from running after 10 minutes(or 20 minutes in this case) has gone by. This appears to be a failsafe, therefore it should have precedence. Therefore, and this is just my opinion, if the thermoswitch is bad(and causes the fans to run all the time instead of them not running when they should) it will of course cause the fan to run by having continuity at all times at the switch or it would be open(however I've never heard of a fan switch being bad and causing it to have continuity, normally they just stay open which causes the fan never to run, but I suppose it is possible), however the fan timer, if good, should stop the fan from running after 10 minutes(again, 20 minutes in this case as given by Lost). However, if the fan timer is bad then it would force the fans to work no matter what. Again, this is my opinion based on what, in theory, would make sense.

Re: 91 Accord: radiator fan keeps running after car is off....then, dead battery.
 

91 acura integra - tracking down causes of repeated dead battery. While we were using volt meter to check battery charge with car running and with it shut off noticed cooling fan came on with cold engine when engine was shut off. So then stared thinking one of the thermoswitches or timer was bad. Concluded that battery needed to be replaced regardless and was planning to start checking thermoswitches but after new battery installed the fan quit coming on at odd times with cold engine. Is it possible the low voltage state from the bad battery was causing the thermoswitches and fan timer to do miscommunicate and cause the fan to come on randomly?

Re: 91 Accord: radiator fan keeps running after car is off....then, dead battery.
 

Not at all. Seems like it's a coincidence. There's another culprit.