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Need help!! Fans not working unless jumped or A/C on (only for 1 minute)
Hi all,
I have read over and over again almost a hundred forums and I just can't figure this problem out. I have checked and change everything people have mentioned. 2002 Honda Civic EX Coupe.
I changed thermostat twice, coolant fan switch off the radiator hose 3 times, ect sensor twice, new fan, known relays (even bought new ones and tested with other relay slots like horn), all fuses are good, bled the coolant multiple times for over hours. Idk what the problem is. The fans DO work when I hit the A/C on or jump with a paper clip at the coolant switch coming off the thermostat housing. Problem too is when I hit the A/C button and the fans turn on, it only stays on for about a minute. Is it maybe a wiring issue?? Ground issue?
Any help would be super appreciated!! Thanks in advance.
Last edited by bladeserpent; Mar 20, 2024 at 11:06 AM.
Re: Need help!! Fans not working unless jumped or A/C on (only for 1 minute)
So if your temps are getting to the red, your fans are not going to help the issue. You should be able to drive highway speeds, without the fans going and not have overheating issues. Is your coolant overflow filled? I would seriously be considering a blown head gasket, if it's getting that hot.
Last edited by chozobody; Mar 20, 2024 at 11:17 AM.
Reason: spelling
Re: Need help!! Fans not working unless jumped or A/C on (only for 1 minute)
Originally Posted by chozobody
So if your temps are getting to the red, your fans are not going to help the issue. You should be able to drive highway speeds, without the fans going and not have overheating issues. Is your coolant overflow filled? I would seriously be considering a blown head gasket, if it's getting that hot.
It is a bit of a consideration, but the car does drive weeks on end just fine, highway included. Having the fans on seriously helps in bringing the temps back down when daily driving. It feels as though because the coolant is not being cooled efficiently cause of no fans, it overheats. And again, the fans are just not turning on regardless of the temperature
Re: Need help!! Fans not working unless jumped or A/C on (only for 1 minute)
Originally Posted by bladeserpent
It is a bit of a consideration, but the car does drive weeks on end just fine, highway included. Having the fans on seriously helps in bringing the temps back down when daily driving. It feels as though because the coolant is not being cooled efficiently cause of no fans, it overheats. And again, the fans are just not turning on regardless of the temperature
If I can ask, are you located in a warmer climate?
Re: Need help!! Fans not working unless jumped or A/C on (only for 1 minute)
Originally Posted by chozobody
If I can ask, are you located in a warmer climate?
I'm in Maryland, we get all 4-seasons, but it doesn't get that cold. lowest is 20 degrees, but it gets very hot here like 85+ humidity. Luckily lately it has been cool, but i can imagine i'll have overheating issues in the summer again.
Last edited by bladeserpent; Mar 20, 2024 at 12:53 PM.
Re: Need help!! Fans not working unless jumped or A/C on (only for 1 minute)
Do you have to keep topping up the radiator? I don't want to keep pointing to the head gasket but it's a very common issue with these engines.
You can drive around all you want with no fans and will only have overheating issues when idling for a long time or while in slow traffic. At least as long as there's no head gasket leak.
Re: Need help!! Fans not working unless jumped or A/C on (only for 1 minute)
Originally Posted by BrotatoChip
Do you have to keep topping up the radiator? I don't want to keep pointing to the head gasket but it's a very common issue with these engines.
You can drive around all you want with no fans and will only have overheating issues when idling for a long time or while in slow traffic. At least as long as there's no head gasket leak.
That is exactly what is happening. It will start to overheat randomly after awhile.
Re: Need help!! Fans not working unless jumped or A/C on (only for 1 minute)
I didn't make myself clear. I'm saying you should basically never overheat even if the fans are not working. The airflow through the radiator while driving is better at cooling than the fans could manage anyways. So, as long as you're not in standstill traffic or idling for 10+ minutes, it won't overheat without fans.
The radiator fan switch is located on the coolant neck, passenger side of the cylinder head. It should close to turn on the fans when coolant reaches 199F (93C). You've replaced this already?
If there is air in the coolant system (like from a leaking head gasket or from coolant being low) it can prevent the fan switch from working. If you really think this is a fan issue, jump the fan switch with a paperclip and leave it in. Fans will run continuously with ignition on. I bet it still overheats after a while.
Fans only running for ~1 minute with A/C on is likely a separate issue with your A/C. I assume it stops working after ~1 minute as well?
Re: Need help!! Fans not working unless jumped or A/C on (only for 1 minute)
Did you ever find your issue?
I have a similar situation. Mine won't overheat but I had the car running at a high idle to cycle an engine cleaner through before a recent oil change. I noticed the temp get over 210F without the fans coming on. Paperclip jumped it just fine. Replaced the coolant temp sensor and the fan switch and still no fan on over 210F. I burped the system as well.
Not trying to hijack here, just have very similar symptoms and I can't figure it out. The first time I had the car at a higher temp some coolant bubbled over and now there's foam through the overflow tank. I wonder if that foam/goop is clogging the water jacket and not allowing the fan switch to function properly.
