So ever since i washed my engine bay i had this problem, my radiator fan turns on randomly when ever the car is cold and has been sitting all night. It also happens after i wash my car.

I had it turn on , on me 8 times this month so far and its a pain because it drains my battery.

ps 95 accord lx

When i took of the switch from the thermostat housing and put a paper clip in the +/- the fan started working. Does this mean anything?

I also checked the switch in front of the engine under the distributor but the fan didn't turn on.

PS. how to i wire fan to battery to see if it works.
I took some 18 awg wire from the A.C fan switch to the battery and nothing happened.

 

There is a thermal switch that is inline with the top radiator hose, unplug it and blow out all the water that got in there from the engine wash.
When the fans start running on a cold engine unplug that sensor to see if the fans turn off; if that happens replace the switch.

 

which switch are you referring to?

 

The yellow dotted circle

 

ok and where is the switch that i would have to replace?

 

well the fan turned on again and i took of the sensor below distributor and nothing, then i took of the one from the thermostat and nothing.
the only way it turned of was when i pulled the fan relay, but it started up again after i put it back in so currently relay is out of teh car.
the only way that i can turn it of for a good while it take of negative battery terminal.

 

My bad, I don't have flashbacks as well as I used to
You have both temp switch A and B at the T-stat
The one in the yellow circle of the pic is the temp sensor for the ECU in the head.
Temp switch A is on the T-stat housing and B is on the T-stat cover.
B is the one to unplug, it's the one that can turn on the fans when the engine is off.
Temp switch B will have White/green stripe wire and black wire going to it.
There should not be continuity thru the switch below 217 degrees.
Sorry didn't mean to lead you astray.

 

its ok.
You the only one helping me anyway.
At the T-stat there is only 1 plug going in.
the other one is under distributor.
There are also 2 other sensors under the distributor going into the head. but i dont think those are relevant.

I checked the wires and the one on the t-start is green, black
the one under the distributor is white /green stripe, black

 

so let me get one thing straight, The metal piece that is in the housing that actually sees coolant is just the sensor correct?
and the green clip that i connect to that is the switch?

 

They act as switches, when the temp rises it closes the switch [continuity]
The one in the head for the ECU temp sensor, is a sensor. It has a thermistor in it so it passes different voltage at different temp, because the resistance varies. Also the single pin temp sending unit in the head varies it's resistance in the ground path of the temp gauge circuit.

The green clip that fastens on is just the connector, the actual switch part is in the unit that screws into the housing

 

Interested to see this guy being able to solve the problem.

 

I got it. thanks just like if i put the paper clip in the connector it closes and the fan runs. when its open the fan doesn't run.
so in conclusion i need a new engine coolant temperature sensor, correct?
Just to clear things up for me since i am a noob, so this sensor is located.... where?
for the good info hondadude

 

I believe Mr Hondadude is referring to temp switch "B" That is located in the housing cover of the Thermostat.
You have been provided the wiring colors, and that should aid you in locating the correct switch.
As stated in the prior post, the switch can be tested for continuity, this will ensure the the problem is accurately diagnosed.

 

well the one one on the t-stat cover or housring. dont remember but there is only one switch there. Also the color of the wire is just green for + and black for - , when i checked for continuity this morning it just was 1 all the time.

The sensor along side the upper radiator hose, the one circled had the white with green stripe wire. so now im confused.

 

The angle of the picture makes it hard to see if that circled one is in the head or in the line of the radiator hose, but in any event; Temp Switch "B" has the White/green stripe wire and a solid Black wire. And that is the one you need to test.

 

Here i took some pic, hope it helps

Pic 1, Rear of block in t-stat (green,black wire) This is the connecter when i jump it with a paper clip the fan turns on.


Pic 2 front of block (white w. green stripe, black wire)



Pic 3.

 

Woooo Hoooo I didn't even need my bifocals for those pics LOL
1st pic is temp switch "A" and should turn on the fans if connector is jumpered, yet no continuity thru the switch with cool engine.
2nd pic is Temp switch "B" Turns on the fans thru the fan control module if the engine is still hot after shut down. should have no continuity with cool engine.
3rd pic shows the single pin connector that is the ground wire of the Temp Gauge, it is a grounding thermistor.
The grey 2 pin plug in the 3rd pic is the temp sensor for the ECU, also a thermistor, that changes voltage depending on temp so the ECU can make decisions about how to control the timing, spark, injection pulse, whats for supper, ETC...

 

Very nice dude. may i ask where you learned all this from?

And i replace what is in pic 2 right

ps. i checked the contentuity this morning on a cold engien and the switch B on pic 2 was reading around 700

 

Great, That switch is trash, yank it out of there, and see how far you can throw it.
Where did I learn all this? Hmmmmm...... I started working at a Honda dealership in 1982......and then wasted the next 20 years of my life.
When flat rate pay was cut in half in 02, I went and found a nice gravy job working on other things.
And now if a design engineer makes a mistake that causes a recall, or there is warranty work, I don't get my pay cut to 1/4 of normal flat rate.

 

I was having the same problem and am going to replace all three of those sensors....if I take off all three and take them to advance auto parts will they know which is which or is their like specific names for each sensor and or part numbers so I can make it easier on them?

The word VTEC at my nearest advanced auto parts is like arabic to a chinese man.

FYI im overhauling my cooling system anyways so everything is getting replaced.

 

ok I've come to find out both the green and the grey sensors pictured above all are the same shape and share similar connectors....now pictured below are pictures of the sensors that I purchased today....can the large (BLACK) sensor pictured below fit into place of all those large sensors (GREEN - GREY pictured above) and will it function the same?



FYI-The smaller sensor if very straight forward we all know where its placed.


sorry if im threadjacking but two similar theads at the same time seems rediculous....besides were troubleshooting the same issue.


Modified by Grandhustleman86 at 3:45 PM 5/30/2008

 

hope you find out, honadude has been a big help!

 

Okay THREADJACKER I have no way of knowing if Advance Auto has cross reference listings.
NO you cannot put a Sensor in place of a Switch
I explained the difference in an earlier post.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by gianinline &raquo;</TD></TR><TR><TD CLASS="quote">Interested to see this guy being able to solve the problem.</TD></TR></TABLE>
Ha.... done deal. Problem solved.

I've never met a Honda that I couldn't fix.

However, I've never been able to diagnose and repair STUPIDITY

The OP of this thread was willing to provide correct and accurate information, so it makes it easy to provide him with correct and accurate diagnostic information.
And that is what this forum should be all about.
IMHO

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hondadude &raquo;</TD></TR><TR><TD CLASS="quote">Okay THREADJACKER I have no way of knowing if Advance Auto has cross reference listings.
NO you cannot put a Sensor in place of a Switch
I explained the difference in an earlier post.
</TD></TR></TABLE>

1. <TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Grandhustleman &raquo;</TD></TR><TR><TD CLASS="quote">sorry if im threadjacking but two similar theads at the same time seems rediculous....besides were troubleshooting the same issue.</TD></TR></TABLE>

Pretty good at beating a deadhorse huh?

2. <TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Grandhustleman &raquo;</TD></TR><TR><TD CLASS="quote">or is their like specific names for each sensor</TD></TR></TABLE>

This is gunna be fun.

Ok as stated above I asked "is their "SPECIFIC NAMES" per each sensor"....sorry i didnt say SWITCH also....I dont really have alot of time during lunch to run thru a mitchell or all-data to find all the right nomenclature.

3. You never explained which is which with names pal....like the green switch nearest the firewall is the Rad. Fan switch(pictured above)....the green switch nearest the radiator is the A/C condenser fan switch(pictured above).

YOU labeled them as temp switch A...temp switch B. -You really went into detail ***.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hondadude &raquo;</TD></TR><TR><TD CLASS="quote">However, I've never been able to diagnose and repair STUPIDITY</TD></TR></TABLE>

I really hate doing **** like this but dont you come down on someone else because you didnt ALSO go into detail....I'll keep you in mind next time I need some info.