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Hello -
my fan used to stay/come on when the engine was turned off until it cooled down, usually about 30 seconds.
It no longer does this. The fans still comes on if you turn on the a/c, or if it gets hot enough during regular
driving.
Can anybody tell me the location of the sensor that controls this?
Thanks for any info.
2000 Accord SE 142,000 miles and at the moment, suffering p1486 code
There is a thermal switch on the thermostat housing, but this seems to control the fan while the engine is running -
this works, if I leave the engine idling the fan will cycle on eventually.
But if I turn off the engine when the fan is running, the fan cuts out immediately, where as before it used to stay
on and cool the engine down further.
How is this supposed to work then?
There is another switch under there that controls running the fan (as needed) when ignition is off, but I don't know where it would be on your Accord.
Years ago, I needed Thermoswitch A, but my problem was opposite yours.
Probably, if you use the advanced search here for some keywords in thread titles, you will find some posts that point you to the switch you need. Also, keep in mind that there may be a relay involved. Once you locate the switch under there, you can confirm it't not the relay by putting a jump wire on the connector for the switch.
There is a switch/sensor that I can see under the distributor, maybe that's it, but I thought that one sends a signal for the temp. gauge.
(I could be wrong)
17 is for the ecu, 14 is for the gauges but it was annuled on later cars.
Ok. So it seems the details of how the fans are powered after turning of the engine
and why it is no longer working is, so far, a mystery.
I've pulled off part 15 while the engine is running and jumped the connections and the fan comes on.
But this only works while the engine is running
I'll have to investigate further... Thanks
The fans can be controlled by the radiator fan switch or PCM/ECM.
On a 2000 Accord, the PCM gets it signals from the ECT sensor for various functions, including fan operation and the temperature gauge. The temperature gauge sender on 98-99 Accords was deleted starting with 2000 models.
I have not replaced the thermostat, but I suspect it is involved because the engine takes longer to warm up.
I'm in Los Angeles the ambient temps are about 65f. I would say when all was well within 1 or 2 miles the temp
gauge was steady, in the middle. Now it takes 5 or 6 miles.
Another thing today after about 6 miles of driving, I turned the heater on full to check if it was working normally.
I was not as hot as I remembered; I left it on for a few minutes and the temp gauge dropped back from it's normal position
in the middle back towards the cold mark - I've never seen that before.
I thought perhaps there was air in the system, but the bleed procedure didn't show anythng wrong.. I loosened the bleed valve
at the thermostat housing and the fluid was right there
My neighbor has recommended a mechanic to me, tomorrow or Monday I should know more.
Thanks for the posts, I'll update when I get more info
The problem is finding the switches on these cars.
The thermoswitch should be on the left side of the cylinder head, and I think it has at least one green wire going to it. It may be hiding up under there so look around under the distributor area. It will be inserted horizontally. Sometimes the plugs on those switches completely shroud them, so until you pull the plug off, you cannot see that there is a thermoswitch under it sticking into the engine block.
Pull the plug on that switch and put a jumpwire on it. Engine temperature doesn't matter, since you are bypassing the thermoswitch. Do it with the key on (engine not necessarily running). If the fan starts when you turn the key off, you know the fan relay is good, and of course that the fan is good. So you know the switch is the problem. If the fan doesn't come on, suspect the relay in the under dash fuse box and check it for continuity with a multimeter.
If it's the switch, replace that switch. Unfortunately, the name sounds the same for all of the thermoswitches in Accords. You won't find "Thermoswitch A,B,C or D," when shopping for them. But make sure they know its the one the grounds the fan when the ignition is off and block temperature is 225° or higher. At least that is the engagement temp on my 4th Gen Accord.
Important to jump the switch to rule out the relay in the under hood fuse box not being what is not signaling that fan when ignition is off and the engine block is still super hot.
Because plugs have places where there is nothing but plastic, I have had mixed results with paperclips, so I snipped some metal off of the type of little 4-inch 18-gauge wire connector shown here. It has prongs that make a solid jumped connection.
The problem is finding the switches on these cars.
The thermoswitch should be on the left side of the cylinder head, and I think it has at least one green wire going to it. It may be hiding up under there so look around under the distributor area. It will be inserted horizontally. Sometimes the plugs on those switches completely shroud them, so until you pull the plug off, you cannot see that there is a thermoswitch under it sticking into the engine block.
A 6th generation 4 cylinder Accord doesn't have two thermoswitches like the 4th and 5th gen.
I'm thinking back and this problem with the fan not running at all after switching off the engine, I first noticed it
shortly after the original radiator was replaced 3 or 4 years ago. (To a Denso 221-3215)
However this work was done at a body shop and not the dealer.
Perhaps something was overlooked.
Unfortunately I did not put 2 and 2 together and follow up like I should have
Last edited by davexnet; 03-31-2019 at 11:30 AM.
Reason: info
I'm going to get the thermostat changed today. The mechanic I spoke to said 80% of the time
this code is caused by the thermostat so we're going to try that first.
Thermostat changed, code vanquished. The mechanic showed me a chart on his computer which showed 80% of the time this code's appearance
is resolved by changing the thermostat.
Regarding my fan's inability to stay on after the engine is shut-off, this page mentions "outside air temperature sensor." at the bottom of the radiator.
I don't see that on mine; someting forgotn during my radiator sway 5 years ago? They specifically mention it applies to the 1990 - 2002 models. https://honda-tech.com/how-tos/a/hon...ned-off-376309
Thermostat changed, code vanquished. The mechanic showed me a chart on his computer which showed 80% of the time this code's appearance
is resolved by changing the thermostat.
Regarding my fan's inability to stay on after the engine is shut-off, this page mentions "outside air temperature sensor." at the bottom of the radiator.
I don't see that on mine; someting forgotn during my radiator sway 5 years ago? They specifically mention it applies to the 1990 - 2002 models. https://honda-tech.com/how-tos/a/hon...ned-off-376309
Some of the statements in that link is erroneous.
1. No, the outside air temperature sensor would not apply to 1990 - 1997 models.
2. Even on 6th generation Accords, only Accords with climate control had that the outside air temperature sensor (e.g., EX-L V6, etc.). So, no your SE and other trim levels equipped with manual HVAC would not have that sensor.
3. Think about that link's statement, "It's called the "ambient air temperature sensor" or "outside air temperature sensor. Both sensors read the temperature of your engine's coolant." That is contradictory.
4. The outside air temperature sensor is related to 6th gen Accords for the HVAC climate control system.
I see your point, that it relates to climate control only. How can a sensor that measures the air temperature be on the radiator?
Perhaps there is sensor there that actually controls the fan? I was kind of hoping that since it was in this website,
there might be something to it. Oh well.
I'm back to square one, the car is running fine, no codes now, yet this missing functionality persists.
It seems I may have to contact the dealer. If I find out anything interesting I'll
update the thread. Thanks everybody for suggestions and advice so far
Q1: I see your point, that it relates to climate control only. How can a sensor that measures the air temperature be on the radiator?
Q2: Perhaps there is sensor there that actually controls the fan?
A1: The outside air temperature sensor is not on the radiator like what the link stated. It is located between the area of the radiator and the bumper where air can flow.
A2: From previous post #8 above.
Originally Posted by tech8
The fans can be controlled by the radiator fan switch or PCM/ECM.
On a 2000 Accord, the PCM gets it signals from the ECT sensor for various functions, including fan operation and the temperature gauge. The temperature gauge sender on 98-99 Accords was deleted starting with 2000 models.
If the car is not overheating, there doesn't appear to be an issue.
If the car is not overheating, there doesn't appear to be an issue.
Yes, yourself and others have said this, but I have tested it further. I have let the vehicle idle
until the fan turns on, then immediately turned off the engine. The fan dies immediately.
This is *not* normal operation
However, during normal driving, the car is not overheating so perhaps you could say the whole thing is moot
03-28-2019, 11:21 AM
fan switch location
