Fans wont kick on¿¿

[pullerfan]

ok so i put some fans from a 96 talon into my 98 gst both fans work just fine before i put them in, but they wont kick on and only one kicks on when i have the ac on, all my releys check out to be fine and when i messed with them by groundin them both fans would come on but they wont come on when i'm up to temp and drivin, could it be my thermostat? i'm not really sure where to check now, any ideas?

 

[nickclay9395]

check the t stat.. then re check your fans... there could have been a short after install... also recheck your fuses.. there should be a little white box on one of the fans thats the thermostat for the fans... check to see if that is still connected

 

[97gst_spyder]

I'm having the same problem with mine. Could you describe the box? The only weird thing is that the temp never goes higher than 1/2 the gauge. Is that possible or is something possibly screwed hardcore?

 

[97gst_spyder]

Here's the thing, i just replaced my thermostat, and upper/lower radiator hoses. All OEM parts. I've also bled the system a few times. The driver side fan will come on if i turn the AC on but thats it, and if i do the manual override in vfaq they both come on with no problem.

 

[pj91gsx]

thermostat, pressure cap, fuse or relay, or bad fan motor.

 

[97gst_spyder]

Ok, well i checked the fuse, and the relay. They're both fine. The thermostat is new, and the cap is 3 months old. Also, the fans both work when hooked up to a 12v source.

 

[97gst_spyder]

Anyone?

 

[djalogik]

It can also be a bad ECU since it tells the fans to turn on after a certain temp.

 

[cano86]

That really sounds like a relay even though you said is checked I've had that problem before as well.

 

[97gst_spyder]

Ok, I'll pick up another relay just to double check that. Now is there a way to test the ecu at all?

BTW, thanks for all the help so far

 

[luizdiefenbach]

its probably the ecu transistors / drivers that ground the fan relays on pin 20/21 on the ecu.
I am with the same problem, all is working fine, except the ecu don`t turn the fans on. The fans work when a/c is on and when I manually bypass the relay.

I think we can check this by testing continuity between the lo fan ecu pin and ground when ecdu sees coolant temp above 95C / 200F, so you need a logger and a multimeter.

I will do this test this afternoon, and post the results.

I already took pictures of the 98 GST ecu to someone can point where are the transistors/drivers for the lo / hi fan (pin 20/21)

SO please if you know can you point the fan drivers if the pictures above? most of the parts have a label, so you can just tell the label: ex. Q105, IC12 etc...

You must be logged in to view this image or video.

thanks for the help and the space

You must be logged in to view this image or video.

 

[luizdiefenbach]

well the ecu did not ground pin 21 like it sould above 200F , when I manually ground ecu pin 21 the fan work. It seems that the only problem is indeed the ecu transistors BUT I dont know where it is can someone help me? the pictures of the ecu is in the previous post.

thanks

 

[IEdroStarI]

if i were you i'd just ground them so the fans stay constant and you dont risk them not kicking in.... another option can be to wire them to a switch that will tap into pins 20 and 21.

 

[Rob10_99]

This Isnt a honda forum, stop with the bs in the titles.