Weird Radiator fan

[smufguy]

Okay here is the deal fellas. I have a 89 Efi.

My car fast idles and warms up real nice. But the fan does not turn on by itself for a long ass time. What happens is that, the temp needle goes up midway then only ONE fan (the tranny side, small fan) kicks in, but not the AC compressor side BIG fan. If u unplug the clip from the thermosensor on the bottom of the radiator, and jump it, both the fans kick in.

My car is set to run all the time cuz i jumped the stupid Wire clip for the thermosensor on the bottom of the radiator. Its fine, i got no problem with it, but as u all know the Efis have the fan control module that lets the fan run for 15 minutes after the car is shut off and i want that. also i want the car to run normal, not ghetto rigged, not anymore.

DOes anyone know why this is? Is the sensor bad? if it is, why does only one fan come on? Its just puzzling.

[Blkblurr]

Does the second fan come on when you turn the ac on? That's what the second fan is for.

[accordlxi2.0]

the efi came with a separate module, did u get that when u did the swap?

[smufguy]

the efi came with a separate module, did u get that when u did the swap?

yeah, its the black box under the passenger seat. I got that and two more spare ones too. It also comes with a Subcooling fan relay under the Hood fuse box and i got that too. And the relay and everythign works, but im still stumped.

Blkblurr, I dont have AC, I took it off. Cuz it needed new O-rings and i did not bother cuz it was getting to be winter back then. But i was thinking about just getting my carb wire for the fans, cuz when i had the carb, the fans ran in parrallel wire off of each other so everytime the left came on, the right came on too. SO i was thinking of just doing that.

But i was wondering what it might be. Thanks again fellas. :D. I jsut love when you guys reply in a flash. Makes me feel special. :tongue:

[Blkblurr]

Your one of the guys we listen to. It great to be able to help the regulars and the true honda 3geez people.

[accordlxi2.0]

um . . . .don't mean to sound noob. . . . .but does the fan turn on when the engine off and hot, if not it may b that round gray thing from the fuse box in the engine bay. . . . . .

[Mac]

Well if you jump out the thermosensor at the bottom of the radiator and they come on, it's a good chance that is the problem. If you have a multimeter you can check it by putting temp switch in boiling water and you should get continuity between the 2 contacts. You can also put a thermometer in with it to see at what temperature it closes.

The temp switch applies a ground to the coils of the relays. So when you jump it out that kind of tells you that your fan motors and relays are all working.

Just a heads up: if the temp switch is bad, beware of aftermarket ones. I've mentioned this before. I had a bad temp switch awhile back and went to a few auto stores and their switches never worked. I installed them and the problem was still there. Then I did the boiling water test and they all failed. So if you do buy one I suggest that you test it before you install it.

[smufguy]

Your one of the guys we listen to. It great to be able to help the regulars and the true honda 3geez people.

That means a lot bro. I am glad i can help people to the best i can. besides, my list goes on forever about people i have to thank for getting me to where i am today. Its because of people like carotman and Jim and other caring people on the board like yourself and many others, i was able to do the things i have done to my car and still am driven to come up with new things. this is like a family where everyone gets helped out and criticized if they are acting stupid. i can never be in a better place in cyberspace than 3geez. Its my cyberhome you could say.

[smufguy]

Well if you jump out the thermosensor at the bottom of the radiator and they come on, it's a good chance that is the problem. If you have a multimeter you can check it by putting temp switch in boiling water and you should get continuity between the 2 contacts. You can also put a thermometer in with it to see at what temperature it closes.

The temp switch applies a ground to the coils of the relays. So when you jump it out that kind of tells you that your fan motors and relays are all working.

Just a heads up: if the temp switch is bad, beware of aftermarket ones. I've mentioned this before. I had a bad temp switch awhile back and went to a few auto stores and their switches never worked. I installed them and the problem was still there. Then I did the boiling water test and they all failed. So if you do buy one I suggest that you test it before you install it.

i will do that my man. I got a spare one from the junkyard, i will test that one out according to the shop manual over this weekend and let u guys know how this thing goes, I might get a new radiator anyways, mine is kinda rusting on the bottom.

OH just making sure, the carb and efi underhood fuse boxes are the same despite the code on the cover right? i asked Carotman about it a while back and i vaguly remember him saying it was the same. but i just wanna clarify it again. Thanks again fellas.

[Mac]

Something else to think about. The temp switch (A) on the bottom of the radiator turns on both fans at about 195 deg. The temp switch (B) in the thermostat housing turns on the condenser fan at about 226 deg.

Now if the your radiator has some build up of rust and sludge laying on the bottom, the switch (A) might not be getting hot enough to close.

And if your thermostat is not working properly, again switch (A) might not be getting hot enough to close but switch (B) might be.

Just some thoughts.

[smufguy]

Something else to think about. The temp switch (A) on the bottom of the radiator turns on both fans at about 195 deg. The temp switch (B) in the thermostat housing turns on the condenser fan at about 226 deg.

Now if the your radiator has some build up of rust and sludge laying on the bottom, the switch (A) might not be getting hot enough to close.

And if your thermostat is not working properly, again switch (A) might not be getting hot enough to close but switch (B) might be.

Just some thoughts.


The thremostat is brand new and its OEM replacement. If what u said about Switch (A) is right, then both fans should come on like u said. BUt only one comes on, on mine. but when i jump it both come on, it makes no sense. :(

sounds like i am gonna be replacing my radiator sooner than i thought. Well what are spring breaks are for right? Thanks fellas. I will test em out, change my radiator in march. man...... what would i do without you all. :cheers: :)

on the side note. What if i changed my Switch (B) with Switch (A) and run the fans out of em? It should work right? Cuz i have a Spare Switch(A) :D

[Mac]

I'm not saying to change your radiator, just that you mentioned it is old and starting to rust. Just something else to check, that's all. Like you mentioned, only one fan comes on but with switch A jumpered they both come on. That kind of tells me that either switch A is bad or it's not getting hot enough to turn on. I would either check or change with a known good one before pulling the radiator.

As far as replacing switch B with switch A that might be an idea but I'm not really sure if they mount the same without looking at them. Again switch A mounts in the radiator and switch B mounts in the thermostat housing. Not sure if they are the same thread size.

[smufguy]

they are the same size i guess. but i am not gonna worry about it. I need a new radiator anyway, cuz when i got mine, it was from the junkyard for the swap. so yeah, it was rusted when i got it, but i needed it and it was the only good one. besides, its only 95 bux from autozone for a direct replacement so i am not worried, Thanks for the tip about the switches tho, i will do that. besides, i need a coolant change anyway, been running with rusted coolant from the radiator, might be. :D