lexanthon

I have a 1998 accord LX 4 cylinder. I have noticed that neither cooling fans will engage. I changed the thermostat thinking that was the problem and that didnt work. i tried jumping the fan switch on the thermostat housing and they still did not come on. i have been researching to find a solution to this problem with no success. i cant run the ac without the fans because it begins to boil over the radiator overflow tank. i have read something about the engine coolant temperature sensor being bad would maybe cause the fans to also not work properly. where is that located and how do i check to see if the sensor is bad? any info would be greatly appreciated.

GhostAccord

It could be the coolant temperature switch, or it could be the fan relay or fan control module.

The fan switch, is located in the thermostat housing. To test it you need to check it's resistance. As the temperature of the coolant goes up the resistance between the two contacts should go down.

If you pick up a Haynes manual it will have all of the testing procedures for the above mentioned components. I have the manual here, unfortunately I don't have the time to type out all of the steps for each component.

nus_dogg

It can't be a bad ECT; otherwise, you'll have a hell of a time getting your car started as the ECU will be seeing -40 from the ECT and be dumping hella fuel to get it to start.

sublime423

First off lets "keep it simple, stupid!" before you go doing all these checks let's look at the simple checks first. So, both fans don't work? will they come on with the A/C turned on? If yes, you got a bad fan switch, if no you got two bad fan motors. Now let me back up what I am talking about with another quick check. lets say you turn the ignition on (key on engine off) A/C off as well the fans should be off. Disconnect the fan switch which is on top of the thermostat housing it is a two pin connector take a thin and I mean thin paper clip and make a "U" and make the two terminals touch (you don't need to JAM the paper clip into the terminals just touch them together)....this is "jumping" the switch. If the fans come on that will back up the bad switch theory and if they dont I'm saying fans. One more check then I'm out. Plug the fan switch back in and start the engine turn the A/C on. No fans.....take a something and smack the fan motor like a screwdriver or small hammer a couple of times (you are not trying to knock it out the park, just knocking on a door strength) sometimes this can jar a bad fan motor in to working for a short time. If they come back on you must realize that they still need to be replaced. Ok some can say fuses and relays and PCMs and waternators. checking all fuses is not a bad idea but the fact is the fans are ran off different fuses and relays to keep one fuse or relay from shutting down both fans at the same time. If you do all this and want to be for sure here is one last check if you have a Test light, disconnect the fans with the key on engine off and check for power to each fan if you got power check for ground if those check out you got bad fan motors.


I hope this helps.

sublime423

Oops.....Missed that part lol!

bad ECT sensor= check engine light on. BTW the ECT sensor has no control over the fans.

poorman212

ok, this is a few days old, been on holiday so trying to catch up.

Wouldn't the first thing be to put 12v to the motors and be sure they are good? The OP jumped the switch. Either one (a or b) should make the fans run, as long as IF it was thermo a the key was "on".

"sublime"- you might have had that somewhere in that blob of text, I got lost after the first line or two.

lexanthon

thanks for all the advice!!! i jumped the fan motors to the battery and fans didnt start. i put a meter to see if they were getting power and they were. so what i did was hit the motors with a hammer and they finally engaged. i was shocked when they began to spin. ordered new motors today, but will get me through the week with ac again. thanks again!!!

T Wgproductions

I'm glad that I saw this today... I'm having a similiar problem.. My ac compressor, compressor fan and coolant fan won't come on.. I've jumped the fans and the ac compressor.. All of them work when I jump then.. So I ruled out the fans or compressor not working.. Since the window relay and the coolant relay are the same i swapped them.. And the windows still worked So i've ruled out the relay.. I checked the fuse in the car just as a precaution before I posted.. and still Nothing.. I don't understand wtf is going on.. And they all stopped working at the same time.. what is common in these to make this happen

*update* jumped that thermo/fan switch.. NADA .. I need help!

poorman212

TW- What year is this? 4 or 6 cyl?

Which underhood fuse have you checked?

ChrisMaconGa

ChrisB from Macon Ga here. I'm going to check an issue I'm having on a 96 and running hot. I changed the themostat. I've bleed the air very well. I turn on the car and start the ac. Only the left side fan turns on. My inf readings are 158-175.front and back..may not be getting it hot enough to turn the other fan on??

DrJimmieRustles

Have you tried jumping the fan to ensure the motor is good?

backinblue92

iTrader: (1)

I know I'm bumping a way old thread but I'm having a problem just like the final two posts outlined here.

When I turn on my a/c only my driver side fan comes on. The cooling fan stays off. When I jump the cooling fan from the thermostat-mounted ect switch, it works. When I jump it from the underhood relay, it works. So why doesn't it come on with the a/c or actually ever? I of course have a new thermostat, bled it well, etc. But I can't remember the last time that fan came on.. and it's been 100 here the last couple days. The car isn't overheating at all though.

I tried jumping it from the block-mounted ect sensor but I do believe that sensor does not control the fan anyways.

There's great info here in this thread but I'm not breaking it down right in my mind I think.

backinblue92

iTrader: (1)

Well it turns out the cooling fan does come on with the a/c. So why does it not turn on otherwise? Does jumping the switch when the engine is over 195* mean the switch isn't working properly?

holmesnmanny

I really am totally lost as to when it comes on and when it doesn't come on. If I had to take a guess, I would say you're trying to jump the thermoswitch b, which only turns on the radiator fan after the ignition is off.

Again, I'm not too sure what the issue is 'though.

backinblue92

iTrader: (1)

Sorry about that, I was up super early this am and hadn't had my am coffee yet. So I wasn't completely clear.

I assume the accord to be set up just like the prelude and found this thread in a search so I thought it was worth throwing it out there.

After some testing today, my cooling fan doesn't come on unless the a/c is on, during which both fans come on. Independently, the cooling fan isn't turning on. First I jumped the relay, and it came on. Then I jumped the coolant fan temp switch (the plug at the thermostat housing) and heard the relay click and the fan came on again. So I know the relay is good, fan motor, wiring. Thermostat housing is grounded as well.

But I'm trying to nail down why the fan isn't coming on when engine temp passes it's threshold, I believe 195*. I imagine that when I turn on the a/c it closes the circuit on the relay and therefore bypasses the coolant fan temp switch altogether? So that would indicate that it is that temp fan switch malfunctioning?

(I should have left the coolant temp sensor out of my post in the first place, as that has nothing to do with the fan- though it could be a reason my engine is running rich)

holmesnmanny

Are you aware that both fans are cooling fans ? I'm not sure why you keep alluding to a "cooling fan". They are both cooling fans. I still have no idea which fan it is that isn't working.

I'm going to spell it out for you, the passenger fan is the radiator fan. Since you have ac, the driver side fan is the condenser fan.

You could have used either passenger fan, driver side fan, condenser fan, or radiator fan and that would point to which fan you were talking to, but instead somehow you managed to just say "cooling fan".

The more I see your posts, the more I feel like you're just trolling here.

holmesnmanny

WATER PUMP - SENSOR for 1998 Honda ACCORD SEDAN

This is a diagram of your cooling system sensors. You can use that to describe just exactly which sensor you are testing.

backinblue92

iTrader: (1)

I apologize for being more specific than "pass side fan".

Cooling fan = radiator fan = pass side fan
A/c fan = a/c condenser fan = driver side fan

I've never heard the radiator fan referred to as anything other than the cooling fan, as the driverside fan only engages with a/c.

I'm trying to pinpoint why the radiator fan, aka cooling fan, is not functioning except when a/c is on. When a/c is not on, it does not engage at any point. It does not ever stay on after the car is turned off, nor does it ever engage when the car is running. I jumped the thermo switch, number #15 in your diagram, to check that the entire controlled side of the system was working. It is. So I'm trying to ascertain why the controller side of the system (aka thermo switch) isn't activating the fan when temp goes above its degree threshold.

For what it's worth, the car has never overheated and never goes above normal temp. But that doesn't necessarily mean the fan is working properly.

Pilot7

If you jumped the cooling fan switch wiring harness and the fan switched on, then the electrical side of things is working (i.e. fan motor and relay). This means that the switch its self has gone bad. The switch should be open circuit when the engine is cool removing power from the fan. When the coolant temperature goes above 200 degrees the switch should close it's circuit and provide power through the harness you jumped and turn the fan on. You could test the switch before replacing it if you want by checking for resistance (you should have resistance) at operating temperature.

phong1216

Hi guys. I'm taking my chances to get some help.

I have a 1994 honda civic, my condenser fan wont work, then my aircondition started blowing warm air. I already tried to connect the fan directly to the battery and yes it did worked. Checked the fuse and its fine. What should be the problem?

thefew

phong1216 you most likely have a leak in your A/C system. When the pressure drops below a certain threshold (don't ask me what it is because I am doing this from memory) there is a sensor in your A/C system that prevents your A/C clutch from engaging. This protects your compressor from being damaged by low pressure. There are several places a leak can occur. The more common things to check are the valve stems on your low and high pressure side. Try and tighten them up with a valve stem tool. If they are loose you have found one or more leaks. Don't stop there though. On a car as old as yours there could be several other problems. The pressure switch I mentioned can (and did on my 1991 Accord) develop a leak as well. I did not find the leak in the pressure switch until I pulled a vacuum on the system. Unplug the switch and put your finger on the sensor. If the vacuum pump is tugging on your finger the switch has a leak. I also had a leak in my condenser, and I bought a new one. THE WORST thing it could be is a ghetto upgrade from R12 to R134a coolant. If your system came with R12 from the factory, and has been converted to R134a, the compressor is usually ruined if the upgrade is not done properly. Why? R12 and R134a systems use incompatible types of oil to lubricate the compressor. If these two oils are mixed it is buy a new compressor time and flush out your entire system. The solution is to use Ester oil after the upgrade. It will not damage an R12 factory compressor. If your upgrade was done properly (and thoroughly) there will be a sticker stating that the upgrade was done in the engine compartment. They are fairly big stickers, but it could be almost anywhere in the engine compartment. If it was my car I would borrow a set of A/C manifold gauges and a vacuum pump from my local auto parts store and see if there is any pressure in the system with the gauges. If there is little or no pressure you can pop the lines on your compressor and see what the oil looks like. If it is sludge-like you have a bad compressor due to the ghetto upgrade scenario I talked about earlier. If the compressor is good, hook up the vacuum pump and hunt for other leaks. They can be a bummer to find...I also have borrowed bad manifold gauges and vacuum pumps from an unnamed auto parts store ( their initials are Autozone) so keep that in mind too! You also need to pop ALL your line connectors and replace the o-rings. R134a o-rings are green. If you find any black o-rings those are R12 o-rings, and further evidence of a ghetto upgrade. Other parts to replace if you have a discharged system are your expansion valve (under the dash attached to your evaporator) pulling the evaporator and cleaning the cooling fins will pay big dividends too; and your receiver-drier. Put the receiver-drier in after you have fixed all the leaks, and right before you vacuum out the system to charge it up. Hope this helps. There are videos on you tube that can help if this is all new to you. Stick with it and you will save a ton of money on labor costs...Good luck. Oh one more thing it could be is a bad A/C clutch. If the clutch is bad you might be able to replace just the clutch. However, it could be an integrated part of the compressor...and you will have to get a new compressor.

JJ Criss

I know this in an older thread. But i did the jumper trick that sublime said and the fans kicked right on! Great advice and a very simple test. Screw all the relay test! Worked like a charm. Thanks sublime.