I just replaced the thermo switch, and the radiator fan *still* doesn't come
on, even with the AC switched on (the AC compressor fan on driver's side
does come on).

I measured the new thermo switch by putting an ohmmeter across the terminals
and lowering it into a pan of boiling water. After the switch closed I got 1
ohm of resistance. The old thermo switch read 8 ohms. So I guess it was bad?

I'm not sure what else it could be.... shorted one side of the thermo switch
connector to ground does make the fan come on while the engine is running.
There's nothing else in the circuit as far as I know.

The temp guage never rises above 1/3 level (so far). Tegger, you had asked
about the heat output in the passanger compartment. At times, it seems to be
normal. Other times, it seems to be cool, even when the temp setting is over
at max. Could this be due to a bad thermostat or something else?

 

>
> Just in case it got missed by the OP the first time, I'm reposting what I
> said the other day:
>
> "Personally, I think you're barking up the wrong tree here. 1 ohm or 8
ohms
> means nothing. If the temp gauge never gets past 1/3, the rad fan WILL NOT
> START NO MATTER WHAT.
>
> "If you simulated the heavy stop-and-go traffic like I said for AT LEAST 5
> MINUTES, and the temp gauge DID NOT RISE, then your engine IS NOT HEATING
> UP ENOUGH to make the fan come on.
>
> "I do believe you have a bad thermostat. Replace with new **OEM** for $20,
> then report back, BEFORE you spend bigger bucks on the thermoswitch."

Yep, got it - thanks Tegger.

The thermoswitch was only around $20, I did go ahead and replace it. Based
on what you've said, it was probably good and didn't need replacing.

If I replace the thermostat I'll be sure and get an OEM unit. But I suspect
that the engine is just not getting hot enough. The temp guage goes up to
1/3 shortly after starting up and stays there, never going higher.

 

mike-r@earthlink.net (Mike) wrote in
news:mike-r-1602050310480001@dialup-4.249.168.112.dial1.washington2.level
3.net:

> In article <PH8Qd.70$tl3.28@attbi_s02>, "DesignGuy"
> <dontbother@nowhere.com> wrote:
>
>> I believe I've got a bad thermo switch/sensor in my 1995 Honda Civic
>> LX. The radiator fan does not come on when the AC is switched on
>> (though the compressor fan works okay).
>
> If you've come to the conclusion of a faulty radiator fan circuit
> based on activating the A/C, listen up. The radiator and condenser fan
> circuits are isolated from each other. Not all Hondas run both fans
> simultaneously when using the A/C system. Your year Civic does *not*.
> They occasionally overlap in operation when normal engine fan cooling
> is needed with the A/C running. So unless you're having other real
> issues with the cooling system, save your money...
>


Just in case it got missed by the OP the first time, I'm reposting what I
said the other day:

"Personally, I think you're barking up the wrong tree here. 1 ohm or 8 ohms
means nothing. If the temp gauge never gets past 1/3, the rad fan WILL NOT
START NO MATTER WHAT.

"If you simulated the heavy stop-and-go traffic like I said for AT LEAST 5
MINUTES, and the temp gauge DID NOT RISE, then your engine IS NOT HEATING
UP ENOUGH to make the fan come on.

"I do believe you have a bad thermostat. Replace with new **OEM** for $20,
then report back, BEFORE you spend bigger bucks on the thermoswitch."



--
TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

 

ernests131@charter.net wrote in
news:1108594115.484002.237140@f14g2000cwb.googlegr oups.com:


> Tegger, Remco I just checked my 94 Civic(95 engine)
> and with cold start with a/c on the a/c fan runs but
> the rad fan does not run. It takes more than 15 min
> for the engine to warm up enough for the rad fan to
> come on. (temperature about 60F) My rad fan starts
> at about half scale on temp gage.



Like I said...

The rad fan will come on only AFTER the coolant temperature has reached
about 190F.


--
TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

 

TeGGer® wrote:
> "DesignGuy" <dontbother@nowhere.com> wrote in
> news:AiJQd.7373$tl3.1561@attbi_s02:
>
>
> > Actually, I didn't know that. I read otherwise at
> > http://tegger.com/hondafaq/overheati...ndex/index.htm
:
> > "Start the car and turn on the AC (if so equipped). Both fans (AC
> > radiator and regular radiator) should turn on.
> > If the radiator fan is not turning on, the relay, wiring or fan
motor
> > is bad or power is not getting to the fan relay."
>
>
> Hey Remco, is a revision necessary there?
>
>
> --
> TeGGeR®
>
> The Unofficial Honda/Acura FAQ
> www.tegger.com/hondafaq/

Tegger, Remco I just checked my 94 Civic(95 engine)
and with cold start with a/c on the a/c fan runs but
the rad fan does not run. It takes more than 15 min
for the engine to warm up enough for the rad fan to
come on. (temperature about 60F) My rad fan starts
at about half scale on temp gage.
Ernie

 

"DesignGuy" <dontbother@nowhere.com> wrote in
news:AiJQd.7373$tl3.1561@attbi_s02:


> Actually, I didn't know that. I read otherwise at
> http://tegger.com/hondafaq/overheati...ndex/index.htm :
> "Start the car and turn on the AC (if so equipped). Both fans (AC
> radiator and regular radiator) should turn on.
> If the radiator fan is not turning on, the relay, wiring or fan motor
> is bad or power is not getting to the fan relay."


Hey Remco, is a revision necessary there?


--
TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

 

"Mike" <mike-r@earthlink.net> wrote in message
news:mike-r-1602050310480001@dialup-4.249.168.112.dial1.washington2.level3.n
et...
> In article <PH8Qd.70$tl3.28@attbi_s02>, "DesignGuy"
> <dontbother@nowhere.com> wrote:
>
> > I believe I've got a bad thermo switch/sensor in my 1995 Honda Civic LX.
The
> > radiator fan does not come on when the AC is switched on (though the
> > compressor fan works okay).
>
> If you've come to the conclusion of a faulty radiator fan circuit based on
> activating the A/C, listen up. The radiator and condenser fan circuits are
> isolated from each other. Not all Hondas run both fans simultaneously when
> using the A/C system. Your year Civic does *not*. They occasionally
> overlap in operation when normal engine fan cooling is needed with the A/C
> running. So unless you're having other real issues with the cooling
> system, save your money...

Actually, I didn't know that. I read otherwise at
http://tegger.com/hondafaq/overheati...ndex/index.htm :
"Start the car and turn on the AC (if so equipped). Both fans (AC radiator
and regular radiator) should turn on.
If the radiator fan is not turning on, the relay, wiring or fan motor is bad
or power is not getting to the fan relay."

Anyway, I did have to replace the radiator since it cracked. The only money
I (possibly) wasted was installing a new thermo switch ($22) and I learned a
little in the process.

Good to know that another '95 Civic owner's fan doesn't come on with the AC
either. I'll just sit tight and monitor the situation before havnig any more
work done.

Thanks everyone for your help!

 

In article <PH8Qd.70$tl3.28@attbi_s02>, "DesignGuy"
<dontbother@nowhere.com> wrote:

> I believe I've got a bad thermo switch/sensor in my 1995 Honda Civic LX. The
> radiator fan does not come on when the AC is switched on (though the
> compressor fan works okay).

If you've come to the conclusion of a faulty radiator fan circuit based on
activating the A/C, listen up. The radiator and condenser fan circuits are
isolated from each other. Not all Hondas run both fans simultaneously when
using the A/C system. Your year Civic does *not*. They occasionally
overlap in operation when normal engine fan cooling is needed with the A/C
running. So unless you're having other real issues with the cooling
system, save your money...

--
Mike
95 Civic

 

DesignGuy wrote:
>
> I just replaced the thermo switch, and the radiator fan *still* doesn't come
> on, even with the AC switched on (the AC compressor fan on driver's side
> does come on).

I don't believe the rad fan is supposed to come on when you turn on the
A/C. I have seen cars where the rad fan DOES come on with the A/C (e.g.
some model years of the Accord), but I don't think the '95 Civic is one
of them. The '94 wiring diagram does not show a direct connection
between the A/C system and the radiator fan. The only conceivable link
would be that the ECU could turn on the rad fan when using the A/C
(calls for A/C to turn on go through the ECU and the rad fan relay coil
is connected to the ECU in addition to being connected to the thermo
switch). I just checked the behavior of my '94 Civic, turning on the A/C
causes the condenser fan to turn on, but not the radiator fan.

> I measured the new thermo switch by putting an ohmmeter across the terminals
> and lowering it into a pan of boiling water. After the switch closed I got 1
> ohm of resistance. The old thermo switch read 8 ohms. So I guess it was bad?
>
> I'm not sure what else it could be.... shorted one side of the thermo switch
> connector to ground does make the fan come on while the engine is running.
> There's nothing else in the circuit as far as I know.
>
> The temp guage never rises above 1/3 level (so far). Tegger, you had asked
> about the heat output in the passanger compartment. At times, it seems to be
> normal. Other times, it seems to be cool, even when the temp setting is over
> at max. Could this be due to a bad thermostat or something else?

It could be that you don't have a problem at all. This time of year, the
radiator fan on my '94 hardly ever comes on (Northern California, so not
very cold at all). Caroline (who now uses a different name in this NG)
once mentioned that when she did a coolant system bleed, it took a very
long time idling before the rad fan came on on her Honda.

--
================================================== =====
A modest collection of Honda tech info can be found at:
http://www.geocities.com/ng_randolph

 

"DesignGuy" <dontbother@nowhere.com> wrote in
news:yUvQd.978$zH6.947@attbi_s53:


> The temp guage never rises above 1/3 level (so far). Tegger, you had
> asked about the heat output in the passanger compartment. At times, it
> seems to be normal. Other times, it seems to be cool, even when the
> temp setting is over at max. Could this be due to a bad thermostat or
> something else?



Personally, I think you're barking up the wrong tree here. 1 ohm or 8 ohms
means nothing. If the temp gauge never gets past 1/3, the rad fan WILL NOT
START NO MATTER WHAT.

If you simulated the heavy stop-and-go traffic like I said for AT LEAST 5
MINUTES, and the temp gauge DID NOT RISE, then your engine IS NOT HEATING
UP ENOUGH to make the fan come on.

I do believe you have a bad thermostat. Replace with new **OEM** for $20,
then report back, BEFORE you spend bigger bucks on the thermoswitch.


--
TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

 

I believe I've got a bad thermo switch/sensor in my 1995 Honda Civic LX. The
radiator fan does not come on when the AC is switched on (though the
compressor fan works okay). I checked the fan relay by putting 12VDC across
the coil and I hear a click, plus I get continuity across the contacts. I've
bent the pins in case the socket connection is bad. Shorting out the
contacts in the fan relay socket causes the fan to come on, so the fan
itself is okay. That's the disgnostic work I've done so far.

Thanks to Tegger's FAQ, I've been able to locate the thermo switch, but I
cannot figure out how to remove the connector for testing purposes. It's
rotated in such a way that I can't see do undo the connector, and help here?

Aside from the connector, are there any pitfalls I should know about when
replace the thermo switch? It's fairly easy to get to, so I should be able
to do it myself.

Also would like to change the thermostat, but never having done that I need
some assistance. First, in locating it. Then in determine what type it is
(med temp/high temp) and removal procedure. I've read that on later model
Honda's it's on the lower radiator hose but I can't see it.

 

DesignGuy wrote:
> >
> > The connector to the thermo switch has "lock" that must be raised
about
> > 1/16 of an inch before it can be unpluged. You may have to back the
> > thermo
> > switch a quarter turn or so to get to this "lock". The thermostat
is a
> > couple
> > of inches to the right of the thermo switch an a bit higher. Be
aware
> > that
> > there is still antifreeze in this part of the engine even after you
> > drain
> > the radiator. See Tegger's FAQ under radiator does not come on by
> > REMCO
> > for a lot of good data.
> > Ernie
> >
>
> Thanks, Ernie. I lifted the tab with a screwdriver and it popped
right off.
>
> I ended up running a wire from the thermo switch connector to ground,
so the
> radiator fan stays on when the car is running. I've already purchased
the
> replacement thermo switch, but need to go back and get a wrench big
enough
> to put it on.
>
> One other thing I noticed was that the radiator was under pressure
even
> after 2-3 hours of sitting. Attempting to remove the rad cap cause
coolant
> to squirt out. I would have though any pressure would have dissipated
during
> that time.
Yeah, 2 or 3 hours does seem to be a long time for the radiator to
cool.
When I was having trouble with mine It would cool in an hour or less.
There could be a problem with the radiator cap or the line to the over
flow tank. When the coolant gets hot it should expand and flow into the

overflow tank and then be drawn back into the radiator as the engine
cools. I see a lot of talk about having air in the hoses or the engine
on this news group, but I don't know if that could be your problem.
I think the rad cap should allow coolant to flow to the overflow tank
at about 16 lbs pressure.
Ernie

 

DesignGuy wrote:
> >
> > The connector to the thermo switch has "lock" that must be raised
about
> > 1/16 of an inch before it can be unpluged. You may have to back the
> > thermo
> > switch a quarter turn or so to get to this "lock". The thermostat
is a
> > couple
> > of inches to the right of the thermo switch an a bit higher. Be
aware
> > that
> > there is still antifreeze in this part of the engine even after you
> > drain
> > the radiator. See Tegger's FAQ under radiator does not come on by
> > REMCO
> > for a lot of good data.
> > Ernie
> >
>
> Thanks, Ernie. I lifted the tab with a screwdriver and it popped
right off.
>
> I ended up running a wire from the thermo switch connector to ground,
so the
> radiator fan stays on when the car is running. I've already purchased
the
> replacement thermo switch, but need to go back and get a wrench big
enough
> to put it on.
>
> One other thing I noticed was that the radiator was under pressure
even
> after 2-3 hours of sitting. Attempting to remove the rad cap cause
coolant
> to squirt out. I would have though any pressure would have dissipated
during
> that time.
Yeah, 2 or 3 hours does seem to be a long time for the radiator to
cool.
When I was having trouble with mine It would cool in an hour or less.
There could be a problem with the radiator cap or the line to the over
flow tank. When the coolant gets hot it should expand and flow into the

overflow tank and then be drawn back into the radiator as the engine
cools. I see a lot of talk about having air in the hoses or the engine
on this news group, but I don't know if that could be your problem.
I think the rad cap should allow coolant to flow to the overflow tank
at about 16 lbs pressure.
Ernie

 

Nightdude wrote:
> Incorrect,
>
> my Acura Vigor price for the thermostat was 86$ sale price, 110$ regular
> price. Plus 11$ for gasket!

damn. ida taken it out, got a part number off it then cross-referenced
online. its almost gotta be shared with something else.

then again, thats the wacky 5 cyl, huh?

 

>
> The connector to the thermo switch has "lock" that must be raised about
> 1/16 of an inch before it can be unpluged. You may have to back the
> thermo
> switch a quarter turn or so to get to this "lock". The thermostat is a
> couple
> of inches to the right of the thermo switch an a bit higher. Be aware
> that
> there is still antifreeze in this part of the engine even after you
> drain
> the radiator. See Tegger's FAQ under radiator does not come on by
> REMCO
> for a lot of good data.
> Ernie
>

Thanks, Ernie. I lifted the tab with a screwdriver and it popped right off.

I ended up running a wire from the thermo switch connector to ground, so the
radiator fan stays on when the car is running. I've already purchased the
replacement thermo switch, but need to go back and get a wrench big enough
to put it on.

One other thing I noticed was that the radiator was under pressure even
after 2-3 hours of sitting. Attempting to remove the rad cap cause coolant
to squirt out. I would have though any pressure would have dissipated during
that time.

 

DesignGuy wrote:
> >
> > The thermostat is at the TOP of the engine, where the heat goes.
The lower
> > hose is a long, snaky thing that goes from the bottom of the rad to
the
> > thermostat housing. Follow the hose from the rad to the other end
and
> there
> > it is.
> >
> > WORD OF WARNING:
> > DO NOT INSTALL AN AFTERMARKET THERMOSTAT. Those things are much too
likely
> > to cause you no end of grief. An OEM (and gasket) is less than $20.
> >
> > There is only one rating of OEM: 90C/194F. DO NOT install a cooler
one!
>
>
> I'm confused. I was thinking that was the thermo switch/sensor, since
it
> labeled such on the FAQ:
>
http://www.tegger.com/hondafaq/overh...ndex/index.htm
> (photo next to "Thermo Sensor Check")
>
> Are the thermo sensor/thermostat one and the same?
>
> Also, tnx for the tip on using an OEM part, I'll be sure to do that.

DG, in your post refering to the photo in "Thermo Sensor Check"
The brass colored Sensor is the Thermo Switch. The wires under the
bolt to the right are ground wires. The bolt there holds the cover
to the thermostat, the hose on the right side of the picture is the
lower radiator hose. Remove this hose and another bolt(or two) and
the cover for the thermostat comes off.

 

"DesignGuy" <dontbother@nowhere.com> wrote in
news:dN9Qd.68973$eT5.23856@attbi_s51:

>>
>> Does the rad fan come on when the engine has been in heavy traffic
>> for 5 minutes?
>>
>> Warm it up all the way, take it to a quiet side street somewhere, and
>> then simulate heavy stop-and-go "inch forward" traffic for 5 minutes.
>> If your fan is not coming on, the temp gauge will begin to rise.
>
> I forgot to answer this part -- no the rad fan does not come on,
> whether driving at speed for a while or stop-and-go. The temp guage
> doesn't rise to much, no more than 1/3 of the way up.
>
>
>
>


Sounds like your thermostat may be going bad. You should be up to just
below the half-way mark on the gauge in less than ten minutes of driving.

How's your heater output?

The rad fan will NOT come on until the coolant temperature is high enough
to close the contacts in the fan switch. You may never be getting there.

--
TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

 

"DesignGuy" <dontbother@nowhere.com> wrote in
news:sL9Qd.1522$4q6.638@attbi_s01:

>

>
> I'm confused. I was thinking that was the thermo switch/sensor, since
> it labeled such on the FAQ:
> http://www.tegger.com/hondafaq/overh...ndex/index.htm
> (photo next to "Thermo Sensor Check")
>
> Are the thermo sensor/thermostat one and the same?


No. The thermostat is a big round mechanical thing about 2" in diameter.
It's inserted into the coolant stream and is supposed to block coolant flow
until a proper temperature is reached. The only way to change it is to
drain the coolant and remove the thermostat housing.

http://tegger.com/hondafaq/misc/thermostat.jpg

All the other things are electronic and serve to turn fans on and such.
They might tap into the coolant stream so they can sense the temperature,
but you can usually change them without draining the coolant.



--
TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

 

"Nightdude" <nightdude@rogers.com> wrote in
news:AO9Qd.2016$dZ.165174@news20.bellglobal.com:

> Incorrect,
>
> my Acura Vigor price for the thermostat was 86$ sale price, 110$
> regular price. Plus 11$ for gasket!


Whooooa! Mine was $12 at the dealer. I've NEVER bought an OEM thermostat
for any make that was more than $20. Maybe I'm buying the wrong cars.


>
> 15$ at Canadian Tire... I still bought the OEM.


You won't regret it.


--
TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

 

Incorrect,

my Acura Vigor price for the thermostat was 86$ sale price, 110$ regular
price. Plus 11$ for gasket!

15$ at Canadian Tire... I still bought the OEM.

Adrian


"TeGGer®" <tegger@istop.c0m> wrote in message
news:Xns95FDAEB1818Eteggeratistop@207.14.113.17...
> "DesignGuy" <dontbother@nowhere.com> wrote in
> news:PH8Qd.70$tl3.28@attbi_s02:
>
>> I believe I've got a bad thermo switch/sensor in my 1995 Honda Civic
>> LX. The radiator fan does not come on when the AC is switched on
>> (though the compressor fan works okay). I checked the fan relay by
>> putting 12VDC across the coil and I hear a click, plus I get
>> continuity across the contacts. I've bent the pins in case the socket
>> connection is bad. Shorting out the contacts in the fan relay socket
>> causes the fan to come on, so the fan itself is okay. That's the
>> disgnostic work I've done so far.
>
>
>
> Does the rad fan come on when the engine has been in heavy traffic for 5
> minutes?
>
> Warm it up all the way, take it to a quiet side street somewhere, and then
> simulate heavy stop-and-go "inch forward" traffic for 5 minutes. If your
> fan is not coming on, the temp gauge will begin to rise.
>
>
>>
>> Thanks to Tegger's FAQ, I've been able to locate the thermo switch,
>> but I cannot figure out how to remove the connector for testing
>> purposes. It's rotated in such a way that I can't see do undo the
>> connector, and help here?
>>
>> Aside from the connector, are there any pitfalls I should know about
>> when replace the thermo switch? It's fairly easy to get to, so I
>> should be able to do it myself.
>>
>> Also would like to change the thermostat, but never having done that I
>> need some assistance. First, in locating it. Then in determine what
>> type it is (med temp/high temp) and removal procedure. I've read that
>> on later model Honda's it's on the lower radiator hose but I can't see
>> it.
>
>
>
> The thermostat is at the TOP of the engine, where the heat goes. The lower
> hose is a long, snaky thing that goes from the bottom of the rad to the
> thermostat housing. Follow the hose from the rad to the other end and
> there
> it is.
>
> WORD OF WARNING:
> DO NOT INSTALL AN AFTERMARKET THERMOSTAT. Those things are much too likely
> to cause you no end of grief. An OEM (and gasket) is less than $20.
>
> There is only one rating of OEM: 90C/194F. DO NOT install a cooler one!
>
> --
> TeGGeR®
>
> The Unofficial Honda/Acura FAQ
> www.tegger.com/hondafaq/