2G Cooling issue, plus wiring them up

[spooln4fun]

First off my thermostat housing has all new sensors(2) car starts drives fine......the rad. fan will not kick on what so ever. I have checked my thermostat, the relays, and fuses.
Any onehave any insight on how to correct my fan from not turning on.
OR does anyone know which wire on the fan is the hot wire so i could run it to accesory so it will turn on and off with the car?

 

[luv2rallye]

Let's say I wanted the A/C fan (driver side) running all the time, to help cool off the turbo / exhaust after a hard run and to keep the A/C fan blades from melting.

Essentially, I'd like the C-F position (toggle up) to override the A/C fan alone, and override both fans when in the A-D position (toggle down). Would swapping the pin 20 & 21 wire taps (as illustrated below) accomplish this?

Assuming you have factory fans and wiring, no. Swapping 20 & 21 taps will only power the passenger fan on medium speed when in C-F position.

Also this switch however wired, will only power fans while key is on, not when it's off (this for those who would forget to turn them off).

Actually I discovered after I wrote post 11 that the factory 2g fans work a little differently than the relays imply. Rad fan relay hi (or cond fan relay hi) by itself puts the fan on medium speed - not hi speed. It takes both hi and lo relays to put the fan on hi. [full explaination here: http://www.dsmtuners.com/forums/new...-issue-plus-wiring-them-up.html#post151311484 under "The speeds are..."]. So actually in my diagram the C-F position puts both passenger and driver fans each on medium speeds. A-D position puts passenger fan on hi and driver fan on medium. I just decided to leave the post as is however rather than really confuse people (especially since the relays are labeled hi and lo which is already misleading).

 

[Scott McIntyre]

Assuming you have factory fans and wiring, no. Swapping 20 & 21 taps will only power the passenger fan on medium speed when in C-F position.

Hmmm... Ok, maybe I'm over-complicating things.

I would like to be able to turn the factory A/C fan on medium speed with the flip of a switch (ignition on), while still allowing the ECU to control high speed operation.

Would simply grounding ECU pin 20 via a SPST toggle switch accomplish this?

Thanks.

 

[luv2rallye]

Grounding ECU pin 20 will force both the A/C fan and the radiator fan to be on medium speed. When the ECU decides to turn the radiator fan on medium speed it will ground pin 21, which now will actually turn the radiator fan on high speed because you have grounded pin 20. The A/C fan will stay at medium speed since to go on high speed it also needs the Cond fan relay lo (A-09) activated which only does so when the A/C switch is on (and cabin FIN thermo sensor activated which measures cabin temp).

A complete table that shows when the 2g ECU turns on the factory fans is shown here: http://www.dsmtuners.com/attachments/fan-operating-mode-2g-jpg.86862/. You can see it depends ECT, vehicle speed, and A/C switch.

 

[Scott McIntyre]

The A/C fan will stay at medium speed since to go on high speed it also needs the Cond fan relay lo (A-09) activated which only does so when the A/C switch is on (and cabin FIN thermo sensor activated which measures cabin temp).

I'm guessing the "cabin FIN thermo sensor" is the yellow wired one pictured below (from inside the A/C under-dash condenser box):

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My A/C is removed. So to achieve my goal of running the A/C fan at will, I'll just toggle the A/C button on and turn on the HVAC fan (after I put that thermo sensor back in ).

A toggle switch override would have been nice, but using the factory controls will suffice.

Thanks again.

 

[luv2rallye]

Actually just leave the Automatic compressor ECM (and FIN sensor) off and just connect that ECM's harness blue-black wire to it's green-orange one. But this still requires you to turn on both the blower switch and the AC switch. And without ECU pin 20 grounded you'll only get medium speed on the AC fan.

Instead I'd recommend installing a switch to connect ECU pin 20 to ground and then connect the AC fan's blue-white to it's blue (or on the fan side of it's connector, the blue-black to it's blue). This will make the AC fan go on high when you toggle the switch or when the ECU activates pin 20. [It also makes the radiator fan go on medium (or high if ECU activates pin 21) but I don't think you would mind as this solution is much easier.]

 

[TimF]

Well my turn to bring back this thread. I ran into the same problem on my 1ga Talon. Out of no were my fans stopped working (just so happned my first day of school) So when im at idle (redlights) or driving slow (under 30mph) my car slowly heats up. I have no idea why my fans just stoped working. I was pulled over and some guy pulled up to offer help and said that I should just connect my fans directly to my battery, or make a relay if i want to turn them on or of myself. Any help or opinions please?

 

[luv2rallye]

Don't just connect them to the battery unless it's through a relay with a fuse. But for a 1g why not just disconnect the sensor at the bottom of the radiator. Put a piece of wire in the connector going from one terminal to the other. This will make your fan run whenever the engine is running and will use the original fan relay. You can also wire both fans in parallel if you wish. Or you can try replacing that sensor which is probably the problem.

 

[TimF]

ok thanks i was not to sure on what to do, that wire set up is just something that guy told me, but i trust u guys over him So were exactly on the bottom is the sensor for the radiator, I dont remember seeing one when i was under the car yesterday.

 

[chrysler kid]

Grounding ECU pin 20 will force both the A/C fan and the radiator fan to be on medium speed. When the ECU decides to turn the radiator fan on medium speed it will ground pin 21, which now will actually turn the radiator fan on high speed because you have grounded pin 20. The A/C fan will stay at medium speed since to go on high speed it also needs the Cond fan relay lo (A-09) activated which only does so when the A/C switch is on (and cabin FIN thermo sensor activated which measures cabin temp).

A complete table that shows when the 2g ECU turns on the factory fans is shown here: http://www.dsmtuners.com/forums/attachment.php?attachmentid=86862&d=1219990229. You can see it depends ECT, vehicle speed, and A/C switch.

I'm bumping this because I'm trying to find the set parameters for 2g fan functions. Your link is no longer functional

Need to know specific times where fans turn off, on, high and low

If fans turn off over a certain observed speed, and if those settings can be observed and tested

My condenser fan functions on low when the AC is turned on and the compressor engages

my radiator fan functions only when vehicle is to regulating temperature to kick cooling fan on to lower coolant temp ( as far as I am able to observe)

I'm not able to determine if the radiator or condenser fans function at high setting, or what triggers high setting

Edit: car is a 1998 eclipse gst automatic. There is a bit of jargon back and forth about econ modes for fan settings, and then it gets murkier for a 2gb automatic

 

[luv2rallye]

Here's that link (when the factory 2g fans turn on - 2.0 turbo and 2.4): http://www.dsmtuners.com/attachments/fan-operating-mode-2g-jpg.86862/.

 

[chrysler kid]

Here's that link (when the factory 2g fans turn on - 2.0 turbo and 2.4): http://www.dsmtuners.com/attachments/fan-operating-mode-2g-jpg.86862/.

Thank you!

Both fans should run with ac switched on, so I have an issue with my radiator fan low setting or relay

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[chrysler kid]

Ok, so I've verified continuity from the center pins of the relay slots to the fan

I've verified the fan responds to voltage from the battery

However the fan low relay is only triggered when the condenser fan hi relay is triggered. So all 3 relays are energized at once

So my rad fan low is not being energized by the wiring. Unless condenser fan hi is on

Any suggestions? Car has 3 radiator fan relays

 

[luv2rallye]

The condenser fan high relay and radiator fan high relay are wired together (so activate together) and wired to ECU pin 20. The radiator fan lo relay (L01) is wired to ECU pin 21. Sounds like you may have an AT (or was originally) which has another radiator fan lo relay (L02) which goes on with the condenser fan high relay and radiator fan high relay and is also wired to ECU pin 20. Do you have an AT or was it originally?

If never was an AT perhaps the ECU pin 21 output transistor driver is blown, or it's wiring is not making good contact, or you don't have factory fans, or someone changed the fan wiring.

Note the speeds on the factory fans use combined voltages on their wires. See post #2 ("The speeds are...") for explanation.

 

[chrysler kid]

Always auto, 98 gst engine trans wiring with a 99 gst auto ecu (old ECU had been molested with evoscan)

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I swapped the relays last night in the box with no difference, left the car overnight and it drained the battery and when jumped this morning would not stay running

Came back on lunch after letting it charge all morning, and started it, and now the radiator fan works with the condenser fan, and the car does not have any charging issues

Most likely I have a bad relay, but none of them seem to be energized with key off. I have no idea why I swap the relays and 8 hours later it's dead and acts like the main alternator fuse is blown. All grounds are good and clean, I've added a few grounding points from engine to chassis as well over the years

So yeah the fan relay and the fan are working correctly and there are no more issues. I tested continuity to the fuse box and relays, it appears that what is now the headlight relay is extremely weak. I will have to do further testing to determine if I have a draw, or what possibly drained my 6 month old optima red last night

So yeah everything appears to be fine now. No charging issues and everything works properly.

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