astmd1655

Hey guys,

I've been hitting my head on the wall over this issue for 3 days now. Here's what's happening. I bought my first Accord off someone who must have been a complete "ID 10 T". The original complaint was that the radiator fan was staying on and killing the battery. So this guy cut the wire going to the fan and ran 2 wires into the drivers seat. To turn the fan on you have to twist 2 wires together. Nice. SO... I removed that stuff and connected the wires back together. Fan #1 doesn't come on. Looking at the wire diagram in my Chilton there should be power key on or off and there is 12v at the plug to the relay. Both fan #1 and fan #2 work. The 2nd fan comes on at mid-range temp and also when the A/C button is on. I checked 2 relays at the front of the car which I am assuming are for the fans with a meter and they both open and close as they should when 12v is applied. I have 12v going to 3 wires on the fan relay. Now that I've typed this out that is probably the issue. Why is there 12v to 3 wires... shouldn't only 2 wires have 12v?



Here are the relays at the front, one of which is connected to the radiator fan.



I checked what I labeled as temp 1 and 2. Both are open when cold. #1 is closed when warm and #2 showed 5-6 ohms.

So I'm thinking I should be asking myself why is there 12v going into 3 wires of a relay. Once I solve that then the next question will hopefully be which sending unit is for the fan? The one I labeled 1 or 2? And which goes to the gauge?

In the meantime I'm going back out with the meter. Thanks in advance!

astmd1655

Just read the forum rules... again... I hope it's ok I posted pictures of what I'm looking at. I'll remove them if needed.

astmd1655

OK. Fan relay #2 is actually my A/C compressor relay. Since they are the same relay I switched them and both relays allow the clutch to engage when the A/C is on (just reconfirming that the relays are ok). Fan relay #1 actually has 2 12v wires, 1 wire shows 1.5v, the other feeds the fan. When I ground the coil side of the relay fan #2 turns on. So what am I missing? Also I disconnected the cooling fan relay in the fuse box under the hood. When I do that fan #2 does not turn on.

poorman212

I'm old and slow.......ask this guy..

https://honda-tech.com/forums/honda-accord-1990-2002-2/engine-cooling-fan-problem-please-help-2943520/

Connect everthing back up, the wire the "guy" cut. Then, describe the issue, please?

If the ac is working, when the ac is on BOTH fans should come on....do they?

I'm going to guess Thermo B (you call it, temp #1 is stuck)........cold engine, what is the resistance across the pins of Thermo B?

astmd1655

The "guy"! Too funny. It wasn't me, this time...

1. Thermo B is open when cold and closed when hot (measures no resistance).

2. With the broken wire (white/yellow) connected the radiator fan does turn on and off when the vehicle warms up to the mid point on the dash gauge. When I press the A/C on and the blower motor in the car is on the radiator fan will engage, not the condenser fan (driver side fan). As I said in my first post both fans do work without a doubt.

3. I noticed my temp goes from the middle to 1/4 and back so I'm guessing my thermostat failed open (or there isn't one in the housing) as it's not maintaining a constant temperature. Does that sound about right for a bobbing temperature?

4. When I ground the green wire of the condenser fan relay harness the radiator fan motor engages while the key is in the ignition, not the condenser fan which I thought strange. My thought at that moment was that I had a bad ground. After reviewing the wire schematic it appears all I did was bypass thermo a and the a/c pressure switch.

Tomorrow I will remove my new ground wire so I can try this again. Should I try and jump the terminals of either thermo switch even though I verified that they are functioning? I'm almost tempted lo leave it as it currently is since it is not overheating but the condenser fan is the one that stays on with the fan timer and I really don't want to fry my motor and pay even more money.

Thanks again.

astmd1655

Disregard the bobbing temp gauge. It always helps to cover the basics. I bled my system of air and topped off the radiator. No bobbing.

poorman212

Lets back up just a second....I think we are using different terms. Which is confusing me. By the pic this is a 4cyl, so.

Condensor fan is on the left/drivers side of the car.
Radiator fan is on the right/pass side of the car.

Also in the first pic, one of those relays is for the ac compressor. The other is the condensor fan (left/drivers). The rad fan relay(right/pass) is in the underhood fuse panel.

Jump thermo a (on t-stat housing-lower hose-temp 2 in your pic) with key on, do BOTH fans run?

Jump thermo b (upper hose, temp 1 in your pic) with key off does THE fan run?

Last, info for additional tests if needed, does the ac actually work?

astmd1655

Yes it's a 4 cylinder.

I confused myself on this issue. A couple nights ago I realized which was which. In the future that's how I will describe them.

Found all those and understand.
Thermo A jumped, ONLY the radiator fan energized and functioned.
Thermo B jumped no fans engage. I key on'd and off to verify.
A/C does not blow cold but the A/C compressor clutch engages.

I performed both thermo switch tests with my ground wire removed. I moved my ground wire to the white yellow wire that I repaired from the green wire in the picture. Now BOTH fans engage but they remain on while the key is on.

Yesterday coolant boiled out into my overflow. I replaced my thermostat last night. It did not boil out today and the coolant is remaining in the system.

2 thoughts.

First, my radiator fan control module is not functioning properly confirmed by jumping thermo B correct?

Second, I have a broken wire somewhere between thermo A and the condensor relay. If that is the case I am thinking of moving my ground wire that currently goes yellow/white to ground and connect it yellow white to the green wire of thermo A. When thermo A goes closed circuit the fan "should" engage.

By the way I know this is what this forum is for, but, thank you for your time.

poorman212

Let's keep it kind of simple and then trace back.

To test one of your theories. Key on, or running-jump thermo a and check to continuity from the cond fan relay green wire to green wire on thermo a.


Fan control does a few things but in this test, it only supplies power to the YEL/WHT.

astmd1655

Ha. That's what I thought of!

When I jump thermo A by itself the radiator fan engages only.

With key off I checked continuity of green wire from relay connector to green wire of thermo A (shouldn't have to be key on for that right?). No continuity found. I'm guessing I need to disconnect the old green wire and tie in a new wire to thermo A. That should also allow the condensor fan to engage when the A/C button is pressed as well since the A/C pressure switch shares the same ground. I tried splicing a wire from the green wire of the relay to the green wire of thermo A and nothing happened. Tomorrow I will disconnect the green wire that goes to nowhere and see if my current finally goes where I want it to go with my splice.

-or-

This isn't all because my radiator control module went out is it??? I checked all wires connecting to and going from the radiator fan control module and I have continuity, constant power, and keyed power. I'm checking for voltage with the relay unplugged. Maybe I should check with it plugged in. Perhaps the module can't power both fans at once? If my splice doesn't work tomorrow this may be the next thing to look at.

astmd1655

Ok. Opened my radiator fan control module. There's a burnt spot in the middle. Since power is distributed from this point I'm hoping replacing this module will restore all functions lost.

Unfortunately for me that increases the chance that my overheating is caused by a blown head gasket caused by the faulty timer.

astmd1655

astmd1655

Thanks for the help poorman

Turned out to be the fan timer causing all of my issues.

All fans operate as they should now.

T Wgproductions

what if you jumped therm a and nothing happened? i been having a similar issue.. but my ac compressor, compressor fan , and cooling fan won't come on.. unless i jump them.. i checked my fan control module(timer) and it doesn't look like it has one flaw.. i have power across everything and ground.. (i.e. the jumping from the relay positions caused them to come on)..switched my relays around from the power windows to the cooling fan.. still nothing. I am out of ideas really.. I'm glad to see people solving their issues but i haven't had luck yet

astmd1655

Check the fan timer. I was going nuts trying to figure out my issue. All the relays worked. There was power everywhere that was needed. I checked wires for shorts/breaks between the timer and the relays. Have you tried swapping it with a good timer to see if everything comes back to life?

T Wgproductions

Well ok I went and bought 2 timers from the salvage yard.. Went thru and retested everything I could...

So i switched out the fan timer..

I jumped therm a and both fans ran with key on , i had a bad relay on my ac condenser fan.. (one problem down)

i jumped therm b and turned the key off... fan turned on

I jumped the ac compressor relay and true enough.. the compressor and the fan both came on.. so im guessing bad ac relay??? cause the car does bog down a little when i hit the ac button but compressor never kicks in

my new questions are..

How do i test the ac compressor plug to know if i get a new relay it will work? i have a volt meter but not a test light..

and

Of i jumped therm a.. that means it's the switch for sure that's out?

astmd1655

Mine bogs a little too but that's just the extra drag from the alternator powering the 2 fans I think. Now that all fans work with the switches jumped do they work as they should? When the car is at operating temp the fans comes on? When the car is hot enough and you turn the car off 1 fan comes on? If so you should be able to switch the ac clutch relay and the condenser fan relay as they should be the same (they are on mine).

If that checks out check the wire going to the clutch. My clutch wire was not making contact after I disconnected it so I had to firmly press it back to make contact again. How is the refrigerant?

astmd1655

You can test the clutch by applying 12v to the ac clutch plug. Don't do it for long you can damage your compressor. You should be able to switch the condenser fan relay with the ac clutch relay as well.

If you jumped therm a and the fans work do the fans come on at temp? If the car is overheating and the fans do not come on by themselves I would replace the switch. You can also check the switch by checking the resistance when cold and hot.

T Wgproductions

Well my A/C was working.. it's charged too just had it checked.. if i jump where they relay to the compressor goes.. it comes on .. and the fan turns on too.. what connects the dash to the ac compressor.. im thinking the fault is somewhere in there.. because when i push the ac button on the dash NOTHING HAPPENS, no fans either.. just bogs down like elec. is being applied ??? but no clue from this end..

That's the thing EVERYTHING works when it's jumped that's why im scratching my head confused.. Tomm I'm going to bleed the fluid maybe the fluid isn't making contact with the temp sensors? Just a shot in the dark.. And it just all happened at once.. so i didn't think it was possible for all of this to happen but I'm guessing it is... I am also going to replace the thermostat.. just cause it's cheap and right there..

For the time being im just going to jump the therm a.. so when i turn my car on the fan comes on.. i have things to do it sucks but i gotta goto work tomm

T Wgproductions

[QUOTE=astmd1655;45766441]You can test the clutch by applying 12v to the ac clutch plug. Don't do it for long you can damage your compressor. You should be able to switch the condenser fan relay with the ac clutch relay as well.
QUOTE]

I'm going to try this tommorrow..

astmd1655

Just to confirm, your fans operate properly now with the other fan timer installed and the only issue left is the a/c not operating correct?

The coolant system is separate from your a/c as far as the sensors are concerned. If your coolant system is not bled you should do it anyway though.

I don't know how much more help I can be as I don't have a whole lot of experience in this department yet. Get a copy of a wire diagram and start checking wires and parts. I know there is a diode that is known to go out and there is a thermistor too. I would get my hands on a set of manifold gauges and check your pressure anyway. Then you could jump the relay and see what pressure there is. Maybe there is a leak somewhere?

Again this is out of my expertise so I'm just guessing. Poorman you have any thoughts?

T Wgproductions

[QUOTE=astmd1655;45767152]Just to confirm, your fans operate properly now with the other fan timer installed and the only issue left is the a/c not operating correct?
QUOTE]

No it's not working with the new timer or the new sensor..
the fans still aren't comming on when the car gets hot..
(only have replaced the therm a location)

the only thing that changed was the fact the ac fan spins now when i jump the therm a location

As far as the ac goes.. when i push the ac button on the dash.. no fans come on.. or the compressor.. (which is why i wondered whats the the connection from the dash to the compressor).. *if i jump the compressor the ac fan will come on *

astmd1655

[QUOTE=T Wgproductions;45767721]Ok. You have multiple issues like I did. Take it one issue at a time and you can get this taken care of. Your fans should operate like this:

Both fans on when warmed up.
Passenger side fan on when hot and car off.
Both fans on when ac on (work on later I think)

You said that you jumped both thermo switches and it worked. Check your thermo switches first since the fans operate properly when jumped. They should be open when cold and closed when hot. See what happens from there.

T Wgproductions

[QUOTE=astmd1655;45768108][QUOTE=T Wgproductions;45767721]
Both fans on when warmed up.
QUOTE]

ok i replaced thermo a.. which is supposed to control when the car is on and hot.. i just burped my radiator fluid.. and topped it off.. im about to go drive the car around for a minute and see if the new switch works..


update * new switch still fan doesn't come on.. to me that is a mystery.. tomm i am going to replace therm b switch.. put in a new thermostat.. and my car doesn't even show it's overheating.. is that the coolant temp sensor?

holmesnmanny

Are you saying the needle isn't moving at all ? If your system is working good and it's cold out and you're not driving it, there is a chance that the fans might not need to come on until driven, or atleast idled for a longer duration.

They call that the coolant temperature sender. The coolant temperature sensor is the one next to it that has a plug that tells the ecu what the temperature of the coolant is for air fuel mixture purposes. The sender has a gauge type. It sends the temperature to the dash, hence the name "sender".