I have a 91 Accord LX, and am having some coolant fan issues. I know that the fan is supposed to come on for a short time after the car is off, but mine stays on for a long time (an hour or so) turns off for a little bit, and then turns back on.

I am pretty sure that the fan runs off a different sensor than the temp gauge, but i can not find it anywhere. I tried replacing the fan relay, but that wasnt the problem.

Any help would be great!

Thanks in advance
-Brian

 

hmm, faulty relay maybe? Find it under the hood (big fusebox) and give it a good tap while the fans running. That's pretty messed up, no car stays hot for an hour.

 

Nope, tried the relay.... it must be a sensor or something else.

 

Only thing I can think of is a temp sensor then...ECU doesn't know that the car has cooled down. Does your guage still work?

Just looked at the Helms for you, shows three separate sensors/switches. One an ECT (engine coolant temp I assume) switch (closest to the hose, from the thermostat housting), in the middle is the ECT guage sending unit, and farthest from the housing is the ECT sensor. ECT guage sending unit is self explanatory, that shouldn't cause your problem. Not sure on the switch or ECT sensor, I'd start with them checking for loose connections.

OK here we go, finally found it! To test the ECT sensor unplug it (sounds like just a single wire). Test the resistance (ohms) from the sensor (positive) to a solid ground (black or negative). Starting with a cold engine the resistance should be about 142 ohms at 133 degrees F (or less). From 185 to 212 degrees F the resistance should be around 49-32 ohms. Obviously as the temp rises the resistance will go down.

I hope this gets you headed in the right place! I should also add these specs were from a 94 EX but it should be the same.

 

Schmitey, what year Helm book are you looking at? '94? Honda moved those sensors around sometimes. I think they even changed the logic for running the fan after the key is turned off. I wouldn't trust my '98 book for a '91 car... I tried that once & the older car had the fan switch located somewhere completely different.

 

That is for a 91 accord.

 

That picture would probably help me a lot, but it is hard to read. Is there somewhere that i can look at more pics and dwescriptions?

Thanks for all the help!

 

^

 

give me some webspace and i'll try to post, in the meantime go to the library and look at their manuals

 

So it looks like there's 2 fan switches, one for each fan? Apparently, there's some way they trigger differently when the ignition's switched off. Maybe there's a fan timer in addition to the fan relays (which just switch power). You need a '91 circuit drawing.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JimBlake &raquo;</TD></TR><TR><TD CLASS="quote">So it looks like there's 2 fan switches, one for each fan?</TD></TR></TABLE>

Pretty much. The condensor fan will act like a "overheating" fan. Honda usually sets it high so both fans come on when the car is running hot. The condensor and cooling fan is triggered by the ECU when the A/C switch is turned on.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JimBlake &raquo;</TD></TR><TR><TD CLASS="quote">Maybe there's a fan timer in addition to the fan relays (which just switch power).</TD></TR></TABLE>

You pretty good. You are totally correct.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JimBlake &raquo;</TD></TR><TR><TD CLASS="quote"> You need a '91 circuit drawing.</TD></TR></TABLE>

There you go:


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ismokev8s &raquo;</TD></TR><TR><TD CLASS="quote">That picture would probably help me a lot, but it is hard to read. Is there somewhere that i can look at more pics and dwescriptions?</TD></TR></TABLE>


Sorry, man. Thats the best sizing I can do. I will print it out and snail mail it to you if you like.

 

Awesome!

Usually a fan timer's job is to turn OFF the fan even if the coolant temperature switches are stuck closed.

Turbo, where's the fan timer located? If ismokev8s checked the fan relays, thought he was done, he didn't even look for a timer module...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JimBlake &raquo;</TD></TR><TR><TD CLASS="quote">Turbo, where's the fan timer located? If ismokev8s checked the fan relays, thought he was done, he didn't even look for a timer module...
</TD></TR></TABLE>

 

I can't say I completely understand the control logic for this... Without knowing what's inside the fan timer module.

It looks like it's possible for a screwed-up timer module to energize the condenser fan relay, since it's got control of both (+) & (-) sides of that solenoid.

But it only has the (+) side of the radiator fan relay, so temperature switch "A" has to fail closed. (Maybe it's only the condenser fan that's running????)

If a fan timer is cheap, try a new one. If it's expensive, check out the wiring for shorts & opens first.