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Discussion Starter #1
so my daughters mom rear ended someone about a year ago. we fixed the '03 crv as cheaply as possible. unfortunately i didnt notice the radiator fan was damaged. well recent the blade fell off the fan, popped the 20 amp fuse, and radiator gave out due to over heating.

so we bought a new radiator and fan. i put in in her crv yesterday. today, i filled and bled the cooling system. car is over heating due to the fans not working. A/C fan isnt coming on when the A/C is on either.

fuses are good. relays are good as well. unfortunately, i didnt hook up either fan to a 12v source to test them before installing them. i will do that tomorrow.

Umm, weird thing is, temperature is only climbing about 1/3 up the gauge and stops. is this the reason the fan could not be kicking on? the relay isnt getting a signal from the temp sensor at the bottom of the radiator?

excuse my anatomy of a honda crv, i'm not familiar with this vehicle. is there more than one temp sensor in the cooling system?

thank you for any clues or ideas regarding this. just hoping someone will have experience with this. i'll be going over to her house tomorrow afternoon with the proper electrical tools since i didnt have them with me today.
 

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Hi maachine when the AC cycles both fans should come on no matter what the temp is. Hook up 12 volts to each fan and see if they work. Good luck !
 

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Discussion Starter #3
yeah i'll report back tomorrow and let everyone know what i find. just hoping someone has a little electrical troubleshooting advice.
 

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Discussion Starter #4
ok so i hooked both fans up to 12v power. new radiator fan does work, condenser fan does not

time to order a condenser fan

both fan plugs have 14v going to them when a/c is on. i messed with the contacts in the radiator fan connectors and it does come on now when a/c is on. but it does not come on at all when car gets hot.

the temp gauge in cabin does not go higher than 1/3rd of the way.

so now i am thinking what ever temperature sending unit or sensor is not telling the fan to come on.

i'm aware of the sensor at the bottom of the radiator. is there any other sensors?

anyone have an electrical schematic of the cooling system?
 

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Discussion Starter #6
hey thank you for that. i always forget that the manufacturers have schematics on their websites.

i hooked up my OBD computer to the car and ran it. it's obviously not reading correctly.. it stops at 183* F and doesnt climb any further. this was running the engine around 1800 RPM. so i think i found the culprit.

i'll look into the sending unit and see if something is off. is it plugged into the back of the block? schematic wasnt very clear on that.
 

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Make sure from the pictures that the dead fan is the cooling fan. The shrouds and motors are different. What is the outside temp, with the hood open you may not get the fan to come on with just running the car at a fast idle.
 

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Discussion Starter #8
outside temp was about 70-75 degrees today. the motor is getting hot though. steam is coming out of the radiator cap

i pulled the temp sending unit out, wiped it off, and made sure it was getting a good connection. i put it back in and ran the car one more time with my OBD computer hooked up. i got the engine temp to almost 210* according to my OBD reader. fan still didnt come on. steam started to come out of the cap.

so my daughters mom went ahead and ordered a new condenser fan motor (i do know the difference between the 2, thanks for the heads up though), new temp switch, and new sending unit. it was 70$ for all 3 on rockauto.com including shipping costs. local parts stores wanted 70$ just for the motor and 30$ for each sensor.

by the way, temp sensor is on the side of the motor under the air cleaner housing.
 

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Discussion Starter #9
got the parts in today. will probably work on installing them monday. i'll post back to let you know if it makes any difference.
 

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Discussion Starter #10
so i havent finished the install of the new sensors yet. its been raining all day but i did get the radiator drained and got the new temperature switch installed. i ohmed out the new and old switch, 0 ohms resistance on the new switch and up to 25 ohms resistance on the old one. so i'm guessing that is the problem. gonna install the condenser fan and temperature sending unit tomorrow, burp the system, and report if the cooling fan is working as it should.
 

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I believe that there are two temp sensors, one turns on the radiator fan at around 190F -194F and the other one turns on the condenser fan around 200F. Not sure. They both control relays. So, if neither fan turned on and the fans are good, there is a bigger problem.
Buffalo4
 

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Discussion Starter #12
yeah you know, on some other cars i've worked on, you have a single 2 speed hi/lo fan. so my thought was that with the dual fan setup that this car has, one would act as a high speed fan and the other would work as a low speed fan. i'll test it out tomorrow. shouldnt take me long to get the other parts installed.
 

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I noticed in an earlier part of this post, that you said steam was coming out of the radiator cap. That should not happen even when it gets hot, steam should come out of the overflow tank cap, but not the radiator cap. Perhaps your radiator cap is not holding the pressure it should.
Buffalo4
 

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I was mistaken about the temp at which the rad fan turns on and also about the temp the condenser fan turns on. The
On a 2000 CRV the radiator fan switch is on the thermostat housing and turns on at 196-203F and goes off between 5-14F lower than when it goes on.
Both the rad fan and cond fan relays are powered by fuse #17 (7.5A) in the under-dash fuse/relay box . The radiator fan power is through fuse #57 (20A) and is located in the under-hood fuse/relay box.
Fuse #56 (20A) located in the under-hood fuse/relay box is for the condenser fan.
Fuse #25 (7.5A) in the under-dash fuse/relay box is for the 'coolant temp sending' unit.
There is another sensor ,engine coolant temp (ETC) sensor, unit next to the above one that sends info to the computer, I believe. I think they are near the water pump.



If you cannot get the condenser fan to run (and it is good), try switching the rad fan relay with the condenser fan relay in the under the hood fuse/relay box.
I 'think' the engine computer turns on the condenser fan at a certain temp if the rad fan is not sufficient. I 'think' that it also turns on both fans when the AC is turned on.

Perhaps you can find a free or low cost dl of the service manual for your yr CRV or at least the part you need. I found one for $11 in pdf form and perhaps you can do better. I know I found a free one for a 2000 a couple of years ago.

Buffalo4
 

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Discussion Starter #15
it may have been steam coming off the radiator itself, from spilling coolant. i wasnt 100% sure. i'm trying to burp the system now.

i'll look at the water pump and see if i can find that sensor. and i think your fuse locations are wrong for this 2003 CRV. they must be different cause all the fuses are underhood, not under the dash. i've tested the relays. they are good. i'll report back once i get the system burped and let everyone know if the fan is working or not.
 

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http://www.autofuseboxdiagram.com/wp-content/uploads/2012/09/2003-Honda-CRV-Fuse-Box-Map.jpg
It looks like fuse #1 (20A) is for the Condenser fan, etc and fuse #4 (20A) is for the Radiator fan.

That's why I emphasized the 2000 model. :)

There is an under-dash fuse/relay box and also a under-hood fuse/relay box in the 2003 CRV and they are well described in the Owners Manual (free dl online in case you don't have it).

It also appears that the Radiator fan switch is near the bottom of the radiator and not on the thermostat housing like it is on a 2000.

Overall, you can buy a downloadable .pdf of the Honda 2003 CRV Factory Service Manual for around $10 and get it instantly. Well worth the price which is probably less than a pitcher of beer. :eek:

Buffalo4
 

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Discussion Starter #18
ok so i couldnt get the radiator fan to come on after running the temp up to about 210*. checked fuses and relays, all good.

finally said f it and was gonna run the temp up to 225* to see what happened. BOTH fans kicked on at 217*. did it again and both fans came on again 213* the second time. shut off around 195*. seems strange that both fans would kick on. seems like the radiator fan would kick on before the condensor fan would. can anyone verify that this is correct?
 

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Discussion Starter #19
thanks a ton buffalo4. you've been helpful. i will probably buy the FSM after dealing with this mess.

right, i understood that you emphasized. just not sure of the generation changes and what not so i went outside and looked just to make sure. and yeah i have the owners manual. i double checked that too, after i couldnt get the fans to kick on again.

i hope that this thread will help others in the future. oh and to say, i also ohmed out the temperature sending unit, old and new, they were the same so the old one was fine. 1.756 ohms is what i got at around 80* outside temp.
 

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I believe you could just jumper the radiator fan temp switch connector (at the bottom of the radiator) to see if it turns on the radiator fan. If it does, then the new switch is bad (if that fan doesn't go on when it should while connected and the temp calls for it). If it doesn't turn the radiator fan on, then the circuit is open back to the radiator fan relay.
If both fans come on when it gets hot, I believe that means that both relays are working properly.
The computer will attempt to turn on both fans (regardless of AC or any other settings) when the coolant temp reaches a predetermined max temp.
Do both fans come on when you turn the AC on?

I wish I had an electrical schematic of the 2003 CRV radiator and condenser fan controls. :(
On my 03 Ody, the rad fan can even speed up if needed by having the ground circuit bypass all resistance, if the engine gets too hot.

OK on the test of the temp sending unit. At least now the OBD2 temp readings are probably accurate.

Buffalo4
 
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