use a DMM to test the radiator fan circuit passenger compartment under the dash is fuse 13 which should have a 7.5a. should be around source voltage. 12V under the hood fuse/relay box you need to check fuse 33 which has a 15a fuse, (12v) and tests the fans relay.(keep in mind just cus it clicks doesn't mean the relay is good) this will help you eliminate where your short, open, or high resistance may be. my best guess would be the fan motor GROUND wire needs repair if the relay/fuses check out. Disconnect electrical connector and remove relay. 2. Connect ohmmeter between relay terminals A and B, Fig. 10. 3. Meter should indicate no continuity. 4. Connect battery voltage across terminals C and D. 5. With relay energized, ohmmeter should indicate continuity between terminals A and B.
That happened on my cd5 Accord, car all hooked up for a dyno session and fan wont turn on. All it took was turn the heater all the way to hot to let water circulate and open the water bleed port and tuner was happy and tuning sessuon got started.
if you’re running a jumper harness from car to ecu check the pins in every wire, had a similar ect issue , replaced both sensors only to find one of the pins fell out like a week before. Ik you said wirings fine but worth a shot maybe
Don't put thread sealant on sensors that use the block as a ground, you are going to get a bad signal. But since u did do that, and in order to not take it apart again, try and touch a wire from the back of the sensor to either the block or the chassis. See if that does anything. Also are you sure u are bleeding the system correctly? if there is an air pocket behind the sensor, then it wont work. Take the sensor you took out plug it to the wiring and heat it up with either boiled water or a heatgun to see if anything happens. If the fans kick in then there is air behind the sensor and you need to bleed the system again.
You need to check the hose routing from the head. The thermostat switch doesnt see any hot coolant until the thermostat opens. And from what ive noticed on mine. It switches the fans on when the coolant temperature coming from the radiator is 196 F. The head (Where ECT sensor is) may get a bit hotter than that if the thermostat isnt open yet.
Both upper and lower hoses are super hot to the touch. New thermostat I installed opens at 170° F. Both hoses hot to touch and hondata telling me ect is at 200° F and the fans still dont kick on…. Ive check both fuses and the relay and replaced all 3 of those as well as all 3 coolant sensors/switches and it still doesn’t turn on even when its about to overheat. When I jump the connector that plugs into the thermostat switch the fans turn on instantly… im so confused bro😅
@kriskan8019 the fan works just fine i showed me testing it and i literally showed in this video me setting the temp for the fans to turn on in hondata still doesnt work bro idk
@@brashgarage I didn't catch it in the video but make sure the fanC output from your ecu is wired into your harness or else Hondata won't be able to turn the fans on.
Yessir im going to replace it to be safe but it clicks and tested okay from what I can tell but thats the only thing that hasn’t been replaced yet so ill grab a new one and try 👍
Sounds good ill look into that thanks man. Side note, wouldn’t that green wire be okay if the fans turn on when you jump the thermostat switch? Because as soon as I jump the connector for the thermo switch my fan turns on instantly…??
There's a fan fuse under the dash too
use a DMM to test the radiator fan circuit
passenger compartment under the dash is fuse 13 which should have a 7.5a. should be around source voltage. 12V
under the hood fuse/relay box you need to check fuse 33 which has a 15a fuse, (12v) and tests the fans relay.(keep in mind just cus it clicks doesn't mean the relay is good)
this will help you eliminate where your short, open, or high resistance may be. my best guess would be the fan motor GROUND wire needs repair if the relay/fuses check out.
Disconnect electrical connector and remove relay.
2. Connect ohmmeter between relay terminals A and B, Fig. 10.
3. Meter should indicate no continuity.
4. Connect battery voltage across terminals C and D.
5. With relay energized, ohmmeter should indicate continuity between terminals A and B.
Appreciate this thanks man
That happened on my cd5 Accord, car all hooked up for a dyno session and fan wont turn on. All it took was turn the heater all the way to hot to let water circulate and open the water bleed port and tuner was happy and tuning sessuon got started.
Dang did ur fans turn on throughout the session?
@@brashgarage After it was bled and got rid of the vapor locked. Worked out good.
if you’re running a jumper harness from car to ecu check the pins in every wire, had a similar ect issue , replaced both sensors only to find one of the pins fell out like a week before. Ik you said wirings fine but worth a shot maybe
No jumper harness just all OEM but ill check all the pins just to be sure thanks bro!
Don't put thread sealant on sensors that use the block as a ground, you are going to get a bad signal. But since u did do that, and in order to not take it apart again, try and touch a wire from the back of the sensor to either the block or the chassis. See if that does anything. Also are you sure u are bleeding the system correctly? if there is an air pocket behind the sensor, then it wont work. Take the sensor you took out plug it to the wiring and heat it up with either boiled water or a heatgun to see if anything happens. If the fans kick in then there is air behind the sensor and you need to bleed the system again.
Well shit 💩
There’s a switch right in the driver side wheel well and it’s the high/low speed fan control unit
Ill check that thanks
You need to check the hose routing from the head. The thermostat switch doesnt see any hot coolant until the thermostat opens. And from what ive noticed on mine. It switches the fans on when the coolant temperature coming from the radiator is 196 F. The head (Where ECT sensor is) may get a bit hotter than that if the thermostat isnt open yet.
Both upper and lower hoses are super hot to the touch. New thermostat I installed opens at 170° F. Both hoses hot to touch and hondata telling me ect is at 200° F and the fans still dont kick on…. Ive check both fuses and the relay and replaced all 3 of those as well as all 3 coolant sensors/switches and it still doesn’t turn on even when its about to overheat. When I jump the connector that plugs into the thermostat switch the fans turn on instantly… im so confused bro😅
Check your map, you can change the temperature at which the fans turn on. Also you can test the fan using Hondata it’s pretty easy
@kriskan8019 the fan works just fine i showed me testing it and i literally showed in this video me setting the temp for the fans to turn on in hondata still doesnt work bro idk
@@brashgarage I didn't catch it in the video but make sure the fanC output from your ecu is wired into your harness or else Hondata won't be able to turn the fans on.
I don't remember if you said you tried the fuse, and relay in the fusebox
Yes I checked both fuses and relay. They all looked good but I replaced them anyways and the fans still don't work.
I'd send the fan control circuit diagram
Did you check the fan relay?
Yessir im going to replace it to be safe but it clicks and tested okay from what I can tell but thats the only thing that hasn’t been replaced yet so ill grab a new one and try 👍
It’s your fan switch or relay
Fan switch is fine just replaced it and same with relay
Its one wire from the ecu to the fan control relay its green Draw out the Honda fan control relay on a white board its a very simple circuit
Sounds good ill look into that thanks man. Side note, wouldn’t that green wire be okay if the fans turn on when you jump the thermostat switch? Because as soon as I jump the connector for the thermo switch my fan turns on instantly…??
Shits not even low??
Its so low bro 😂 traction bars like an inch off the ground