Fans dont turn on and overheating

[ahmad89]

I got a new thermo sensor and installed it, filled the radiator, hit the radiator to get the air bubbles out, turned on the car, waited till it warmed up to operating temperature. Drove it around and it seemed fine until when i was leaving my neighborhood it started raising to H a lil then it went back to the middle, it kept doing that for awhile but when my bro turned on the a/c it started going to H. When i was parking back home it was creeping up to H and seemed like it wasnt going to stop. I turned it off and i was stumped. The fans didnt turn on before we drove or after, i think its the wires that connect to the fan and the sensor but CAH tells me i should i wire up a switch but im not good at that stuff but im willing to try it to get my fans to stay on. Any ideas before i wire up the fans to a switch? and how do i wire it up to a switch, details please. Thank you.
P.S. we tested the fans and they spun when we connected them to the battery.

[HondaBoy]

are the fans in working order? if not, could be burnt out motors as one of mine was. see if they come on with the ac switched on. they may not do anything if your ac is not working though. best way to make sure the fans work is use a jumper wire from the battery to the fan's plug, grounding it with another wire.

[LX-incredible]

The AC should turn the fans on whenever the compressor is engauged. Your problems are with either the fan motors, the relays, or the wiring in between.

Test the fans, if they work you can cross the wiring to the fans and fan motors off the list:

That's strange, it should run for longer than that. You can test the fans by running them direct. First remove your under-hood fuse box cover:
http://img163.imageshack.us/img163/3526/overviewft1.th.jpg (http://img163.imageshack.us/my.php?image=overviewft1.jpg)
The second relay from the left is the main cooling fan relay, the round metal relay to the right is the auxiliary relay.
Cut two wires 6-8" long and strip both ends. To test the main cooling fan insert each wire in the two contacts closest to the passenger fender like this:
http://img163.imageshack.us/img163/1885/maincoolingrv8.th.jpg (http://img163.imageshack.us/my.php?image=maincoolingrv8.jpg)
For the hell of it you can also test the auxiliary fan. Insert the two wires in the contacts closest to the firewall like this:
http://img258.imageshack.us/img258/3640/auxcoolingwn4.th.jpg (http://img258.imageshack.us/my.php?image=auxcoolingwn4.jpg)
*Make sure you don't let the wires touch anything, battery voltage is present.
*Check your contacts before connecting the wires.
When the two wires are touched together in the main fan relay slot, the main fan should come on and run for as long as you hold them together. When you touch the auxiliary wires together, the auxiliary fan will come on. If either of the fans don't come on, or run sporadically, the motors need to be replaced/rebuilt
Hope this helps...good luck.

[ahmad89]

The AC should turn the fans on whenever the compressor is engauged. Your problems are with either the fan motors, the relays, or the wiring in between.

Test the fans, if they work you can cross the wiring to the fans and fan motors off the list:
so i just put 2 wires in those places and the 2 ends connect to the battery? and when i do that the fans should come on?

[ahmad89]

I just topped off the coolant and drove the car around, it didnt start overheating for awhile longer but when i got home it started overheating. Im just going to set the fans to a switch inside the car anyone have a good how to on that and which wires would do the job?

[ahmad89]

Ghettogeddy helped me out and gave me some tips too, i will update when i start wiring it up. Thanks for the help everyone.
How do i wire my fans so they can be on when the car is on like messy's?

[LX-incredible]

Check the under hood box fuses # 9, 12, and 14, and #12 in the under dash box.

[LX-incredible]

http://img163.imageshack.us/img163/3526/overviewft1.th.jpg (http://img163.imageshack.us/my.php?image=overviewft1.jpg)
The blank relay slot, covered with a plastic cap, at the top center, is switched with the ignition. EDIT: That pin is connected somehow to the fan control module under the seat IT WILL FRY THE MODULE IF YOU CONNECT SOMETHING TO IT.

[ahmad89]

Im talkin to messy right now and he told how did it, thx for the help everyone and i will let you know how it goes tomorrow asap. Thankyou.

[carotman]

I think your thermostat may be sticking in closed position.

If you drive the car around town, the fans don't really need to work in order for the radiator to cool down. The wind force should be enough. If you come to a stop (or drive really slow) the fans will help.

If the thermostat is sticking, the temp sensor at the bottom of the radiator will never see that super hot coolant since it's blocked at the head. Thus, the fans will not come on.

[ahmad89]

I think your thermostat may be sticking in closed position.

If you drive the car around town, the fans don't really need to work in order for the radiator to cool down. The wind force should be enough. If you come to a stop (or drive really slow) the fans will help.

If the thermostat is sticking, the temp sensor at the bottom of the radiator will never see that super hot coolant since it's blocked at the head. Thus, the fans will not come on.
Should i take out my thermostat?

[carotman]

Well, taking out the thermostat can be a bit of a pain. If you need to replace your coolant anyway, I would do it.

A way to make sure the thermostat is closed is to put your hand on the bottom radiator hose when the car overheats. If it's not hot, the thermostat would be the problem.

On mine, the top hose would be hot but not the bottom. The thermostat restricted flow too much but still allowed the top hose to become hot.

[dlr1989]

Did you bleed the air out of the system using the air bleed value after replacing the coolant? I have seen almost the exact symptoms you are describing when I had an air lock once. If memory serves the bleed valve is on or near the thermostat housing.

[ahmad89]

i didnt bleed it but wouldnt the fans still turn on from hot coolant going to the sensor? i think the thermostat would be the issue. i'll check out the hose like cartman said. Thx for the help and i will update tomorrow.

[dlr1989]

If you haven't changed the thermostat that is of course a possible trouble spot. On the other hand bleeding the air out of the system is something that must be done or an air lock can be present (thats why the air bleed valve is there) and is certainly easier than changing a thermostat. An air lock at the top of the cooling system will act just like a stuck thermostat, including the cooler bottom hose. In either case the coolant stops flowing and the hotter coolant doesn't get to the fan control sensor so the fans don't turn on.

[ahmad89]

I will bleed the air tomorrow and see what happens. If that fails then i will wire it up to a switch. I will check the bottom hose to see if its cool when it starts overheating, if all else fails and non of these work, i will wire up a switch.

[dalinxz]

can you tell us how to wire it here that we we can know and for future reference for anybody who might want to know how to wire the switch and on top of that I would like to know how to wire a switch also.

[ahmad89]

can you tell us how to wire it here that we we can know and for future reference for anybody who might want to know how to wire the switch and on top of that I would like to know how to wire a switch also.
I will try to get the wires and switch today and i will let yall know how it goes.

How to wire up fans to a switch:
From what ghettogeddy told me, you just get a 16 gauge wire, hook it up to the battery, run it down through the firewall and to your switch, get another wire, run it from the fan wires and to the switch. Im not sure if you have to cut the plug off the wires or if you can just stick the wires in the plug.

[ahmad89]

Well i just bled the air out, i bled it 3 times and it didnt start overheating for a long time, longer than usual. I radiator hose that connects to the thermostat housing did get hot so coolant is flowing. Im just going to wire up a switch today, im going to return the sensor i bought and get the wires and switch, anyone know where i can walk in a store buy a switch? i think at autozone and other auto parts places you have to order them. Would Home Depot have switches?

[ahmad89]

I got the wire 100ft of 16 gauge wire and the switch, on the switch it says power, load, ground, does it matter where i connect the wires? and where is the hole in the firewall i couldnt find it and where can i drill in the firewall?

[forrest89sei]

I got the wire 100ft of 16 gauge wire and the switch, on the switch it says power, load, ground, does it matter where i connect the wires? and where is the hole in the firewall i couldnt find it and where can i drill in the firewall?


I'd try to connect to a preexisting ground, like near one of the ones near the Fuses

[ahmad89]

I'd try to connect to a preexisting ground, like near one of the ones near the Fuses
Can you get on aim so we can talk about it? i already added you.

[forrest89sei]

Can you get on aim so we can talk about it? i already added you.


I can't ATM cuz I have to head back into work in a sec.

but I can tonight

[ahmad89]

I can't ATM cuz I have to head back into work in a sec.
but I can tonight
Oh well im trying to get this done today or tomorrow afternoon. but can you tell me where to drill into the firewall? and how thick it is and if i would run into wires?

[LX-incredible]

http://img234.imageshack.us/img234/3466/plugnp9.jpg (http://imageshack.us)

[ahmad89]

I didnt check the fuses yet its been raining all week so i didnt have time, where is that plug at? it looks like its by that bit cricle thing i think thats the master speedometer or something? I can run the wires from the fuse box to the switch then the fans? Can you get on AIM it would be a lot easier and quicker.

[LX-incredible]

Yes, to the left of the master cylinder. I'll be on.

[ahmad89]

Yes, to the left of the master cylinder. I'll be on.
ok, thx

[ahmad89]

UPDATE on the switch. Looks ghetto but i had to melt out the hole from the plastic piece but made it too big so had to go to best tape.
http://i202.photobucket.com/albums/aa156/ahmadr34/PICT4892.jpg
http://i202.photobucket.com/albums/aa156/ahmadr34/PICT4891.jpg

[russiankid]

All you really had to do is take an exacto knife and drill a hole where you want the switch then cut out the plastic.

[ahmad89]

All you really had to do is take an exacto knife and drill a hole where you want the switch then cut out the plastic.
Why dont you get on aim and help me out lol. which wire on the fan wires are pos and neg? they're blue and black i think.

[russiankid]

Why dont you get on aim and help me out lol. which wire on the fan wires are pos and neg? they're blue and black i think.
I am on aim and idk which wires do what, never done this.

[Civic Accord Honda]

i made u a diagram like a good boy :-D wish i knew wich wires where waht on the fans tho :(

[ahmad89]

Anyone know which wire is positive and negative on the fans? they're blue and black.

[carotman]

I radiator hose that connects to the thermostat housing did get hot so coolant is flowing.
Like I said:


the top hose would be hot but not the bottom. The thermostat restricted flow too much but still allowed the top hose to become hot.

Check the bottom hose. THIS is the important hose. Since the temp sensor is at the bottom of the radiator, it needs to "see" that hot coolant in order to kick the fans in.

If you take out the plug at the temp sensor then jump it, the fans have to come on. If they don't it's an electrical problem. If they do, it's either the temp sensor that's fucked to the flow to the bottom of the radiator is too small (sticked thermostat or clogged radiator)

Please, don't ghetto rig your fans like that. It's just unnecessary and will not solve the problem. I could unplug my radiator fans and still be able to drive around town on a 100F day without any overheat. The fans will only make air circulate on the radiator fins. A vehicule driving at 30mph has way more flow than this puny little fan that only covers half the rad anyway...

[ahmad89]

Like I said:



Check the bottom hose. THIS is the important hose. Since the temp sensor is at the bottom of the radiator, it needs to "see" that hot coolant in order to kick the fans in.

If you take out the plug at the temp sensor then jump it, the fans have to come on. If they don't it's an electrical problem. If they do, it's either the temp sensor that's fucked to the flow to the bottom of the radiator is too small (sticked thermostat or clogged radiator)

Please, don't ghetto rig your fans like that. It's just unnecessary and will not solve the problem. I could unplug my radiator fans and still be able to drive around town on a 100F day without any overheat. The fans will only make air circulate on the radiator fins. A vehicule driving at 30mph has way more flow than this puny little fan that only covers half the rad anyway...
I will check the bottom hose tomorrow when i test it again, what if the bottom hose isnt hot but the top one is, does that mean theres a clog in the radiator or the bottom hose?

[russiankid]

I will check the bottom hose tomorrow when i test it again, what if the bottom hose isnt hot but the top one is, does that mean theres a clog in the radiator or the bottom hose?
No, most likely, since you have a new radiator, the thermostat isn't opening all the way.

[ahmad89]

No, most likely, since you have a new radiator, the thermostat isn't opening all the way.
I'll test the thermostat when i get coolant. When would the start open or whatever? For example when the water in the pot boils. I dont think i have the right thermometer.

I wanna thank everyone who helped me figure out the best way to wire this up and for all the advice, ghettogeddy, lxincredible, carotman, CAH for the custom diagram haha and if im forgetting anyone im sorry but thank you too. Just need to see if the bottom hose gets hot or not. I just need to know what would cause the lower hose to not see the hot coolant, like russian not likely a clogged radiator cause its new or newish, so thermostat would be the issue if anything right?

[forrest89sei]

heres some stuff from my honda service manual:

http://img180.imageshack.us/img180/1466/fanthermosensormediumgh8.jpg
http://img185.imageshack.us/img185/8540/thermostattestmediumul4.jpg
http://img228.imageshack.us/img228/6569/fandiagrammediumpn2.jpg

[ahmad89]

ohyea forgot about that page thx, but dam 212 degrees i need a thermometer then.

[ahmad89]

Quick update, i just got back from whataburger since that was the nearest place open cause my parents went out to eat and i was starving. I was sitting in like and waiting for my food for about 20-30min. Last time i did this my car started overheating and the hose that goes from the thermostat housing to the back of the engine sprung a leak from overheating. Well my car stood up extremely well this, and it never went above the middle or operating temperature mark. I will test again tomorrow like i said and check the bottom radiator hose.

[ahmad89]

Here are the pics, sorry took so long but its been raining.
http://i202.photobucket.com/albums/aa156/ahmadr34/PICT4899-1.jpg
http://i202.photobucket.com/albums/aa156/ahmadr34/PICT4896.jpg
http://i202.photobucket.com/albums/aa156/ahmadr34/PICT4895.jpg
http://i202.photobucket.com/albums/aa156/ahmadr34/PICT4894.jpg
http://i202.photobucket.com/albums/aa156/ahmadr34/PICT4893.jpg

[Civic Accord Honda]

nice