evoluti0n12

when i hook it up to the battery straight from the fan, it works, but then when i have it plugged into harness it doesnt work, relay has been changed. Any ideas of what it could be or best way to hard wire to a switch?

thanks in advance

Former User

The fan switch (thermoswitch) is located on the thermostat housing. Unplug the 2P connector and install a jumper wire between the two terminals of this connector. The fan should now run continuously when the key is in ON(II). If so, replace the switch.

civic_driver

I think it runs all the time, even when the key is out. Not sure, forgot to test it last time I was working on the fan.

Former User

Power that activates the radiator fan relay is supplied through the ignition switch.

civic_driver

You're right, I just tried it. I was mistaken with my Renault which runs even when the key is out. I thought it was the same for the civic.

Kista20

9.5 out of 10 times the fan switch relay is bad.

evoluti0n12

i tried that but yet nothing. not sure what it could be

evoluti0n12

thanks btw

civic_driver

When you go to jump that connector there are 4 holes. Two are for the locking mechanism of the plug and the other two are for the wires that go to that plug. You need to jump the two with the wires in them in order to test it appropriately.

When I went to test mine I plugged the jumper in the wrong two because it was dark and I was wondering why the fan doesn't run, even though I knew it worked. So I put up some light to it and figured I jumped the wrong two holes. When I jumped the correct holes, the fan span like it should.

Hopefully that's your problem.

Also, you have to make the car overheat slightly in order for the fan switch to engage and the radiator fan to come on.

evoluti0n12

alright i will try that tomorrow thanks

but right now i just tried to hard wire (ghetto rigged). i got the positive n negative n ran the neg to the neg on battery and ran the positive to heater motor fuse n from there to the switch, then grounded thje switch to chassis. it blew like 4 different fuse. a 7.5, a 15 and 2 20's. did i do something wrong?

civic_driver

Yeah, you overloaded a circuit. It's best if you don't run it straight to a switch and leave it the way it is. Just find what the problem is and fix it.

evoluti0n12

ya, one more question. if i go with a test light, should there be power to the plug for the fan coming from the car?

evoluti0n12

o and i forgot to throw in that sometimes my temp gauge goes passed hot but its not overheating because the plugs aren't melted and it doesnt shut off. when i redline it, then it drops back down. playing with the gas makes it go up and down. i think its the coolant temp gauge. could this be causing it too

Former User

Top off the radiator with coolant and then bleed the cooling system.

What year Civic?

Tell us exactly how you jumped the 2P connector for the fan switch. Pictures would help.

Don't play around like this. You risk causing serious damage to your electrical system by rewiring it without some understanding about the circuits.

evoluti0n12

i havent had time to try and jump the connector, so i will do tomorrow and will show pics if it doesnt work. thanks for the help btw

and its a 2000 LS

jtmartin96civic

i just had this same problem and that scat and jumping the 2wire plug made me realize it was the thermoswitch... thanks for posting this info

SGT_Manny

Ok so I have changed the radiator, Changed the hoses, Changed the thermostat for a failsafe one. Changed the motor on my fan now.

And my fan is still not turning on.

Originally My fan was working then when I changed the entire radiator system and the fan stopped working so I changed the radiator fan motor. (Which damaged my new radiator some!!!!!! -_- But only a few dings which only aggravates me but I know shouldn't do anything really)

I have a new relay for the fan on its way because my with the new motor the fan isn't turning on either.


Now I keep hearing about being able to have the fan run continuously with the ignition key. But I don't know exactly what everybody is talking about. I know there the thermostat housing is and I know what I am looking at but I don't know this switch thing to make the radiator turn on and remain on with the ignition of the car.

I was hoping somebody could help me.

I found this peice online on this website that advertises something similar. Would anybody verify if that switch would do just that and kick in my radiator fan upon ignition key?
The switch piece advertised

jarchul2

Did you find the problem yet because no joke... I've done almost everything you did with this problem only mines a 98 civic.

chope045

just wire a switch in thats always solved my problem

apexi_rsx

^~~ do this or jump the connector and play with ur wires going to the fan. if u have melted wires u should replace it. u could be causing more issues. i know i jumped the thermo plug with the key on and i just had a poor connection or short in my wires near the fan. you should never feed power to the fuse box its already powered from the battery.

jaytiffanys

hey im having the same problem atm with my 2000 ek. ive changed out the thermostat switch and the thermostat it self and everything but the fan still wont turn on. if i stick something like a hair pin down the plug thats suppose to go to the switch it'll turn on can someone help?

btekkkk98

1. Did you check the radiator fan by jumping it with a pin or wire?
-If the fan turns on, replace the thermoswitch (aka cooling fan switch). If the fan does not turn on, replace fan or radiator fan relay.

2. After doing this, try driving it around for 10-15 mins.. After driving it for that time, let it idle and wait for the radiator fan to turn on. Make sure the car does not over heat.

I had this issue because I thought my radiator fan was broke. I jumped the cable that connects to the thermoswitch and the fan turned on. I replaced the theremoswitch because it was old. I drove the car for 10-15 mins, let it idled and watched the fan turn on. The fan will only go on for less than 10 seconds.

It takes a while for the fan to turn on. Be patient and and watch water temp on the gauge. I was freaking out because I was used to my previous car (WRX, RDX, Pilot, 240SX) radiator fan always turning on. I bought a project Civic last summer and I'm now dealing with all issues.

jaytiffanys

yeah ive replaced the thermoswitch already, but it still wont turn on. when i stick a pin into the plug thats suppose to go to the switch itll turn on. so what should i do? my dad think its the plug itself..

btekkkk98

How long did you let the car run for? You know your fan is running and you already swapped the switched.

tim73

Not trying to hijack the thread, but I am having a similar situation. My fan will not start, but I know it works ok, checked relay, fuse and finally jumped harness to switch, which made it start(So I suspect the cooling fan switch). So am I to understand there are three different temperature sensors? One for the ecm, one for the gauge and a switch for the fan? The engine got up to 218(while idleing), which is quite warm, according to my code reader. When I drive, temp runs around 190. Which is ok for alot of cars, but I was under the impression hondas run cooler, say 180? The really crappy part is the stupid gauge never barely budged. The needle sat right beneath the little thermometer picture.

I flushed my coolant today, and the inside of the switch and the inside of the plug is wet. I guess I will try and get my hands on a switch tomorrow. Suggestions?