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1g cooling fan mod - fans are buggy, won't always stay on

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ErikTande

Supporting Member
1,505
561
Dec 17, 2012
Centennial, Colorado
1st Gen Cooling Fan Relay Bypass Mod

I did this mod, and the fans will only come on with the key is turned on. The article says they should turn on no matter what.


I mention that because even when the car is turned on, jumping pins 1 and 3 USUALLY turn the fans on, but not always. If the car is cold, they won't turn on with a switch, and when it's warm the problem is intermittent.


Any suggestions on where to start troubleshooting this?
 
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I'm still having the same problem, the switch doesn't always work. Does anyone have a different way to wire a fan on/off switch?
 
That is one of the poorest mods I've ever seen.
1) The switch is handling the entire fans large current which is very dangerous (could start a fire)!
2) The switch only turns both fans to low speed due to the series condensor fan motor resistor. This is why they sometimes do not turn on in cold weather. The voltage drops in the switch itself and the switch wiring also make the fans run slower and possibly not turn on in the cold.
3) The proper way to wire the fans is to turn the original fan relays on using your switch. Although it would be wiser to turn them on whenever the key is on so you don't have to then always remember to turn them off. This can be done by a) wiring the condensor fan's blue wire with a 12 guage wire going to the radiator fan's blue/red wire and b) disconnecting the thermo sensor at the bottom of the radiator and put a piece of wire in the connector going from one terminal to the other. Both fans will now run when the key is on through the radiator fan relay.
 
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Add a 30-40 amp relay into the circuit and energize it with the toggle switch which should be wired into a "keyed" on source so they turn off when the switch is in the off position. Simple as that. and luv2rallye is trying to point out to use a relay also to take the load off of the switch which WILL burn out in a matter of time due to the load put on it. Electronics 101.
 
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Since the radiator's thermo sensor is what turns them on when engine is too hot (and only when the ignition switch is on), just wire a switch across it (but leave the thermo sensor still wired in). That way you have an override to force them on. When your switch is off they will operate normally. Also since one side of the thermo switch is already connected to ground (all black wire), one side of your switch should connect to the thermo's green/black wire and the other side of your switch to ground. On a 1g I'm told the thermo switch is at the bottom of the radiator (it's not the sensor on the thermostat housing).
 
There's no need to run relays or any of that. The easiest way to manually control the fan is to simply splice into the single wire that runs to the fan switch (As Gary mentioned above), and run it to ground. Put a toggle switch between where you splice in and ground, and boom, you have manual control. Not to mention, the circuit will function just like normal regardless of your toggle switch's position. In order for this to work, the fans need to be wired like stock, and functioning properly.

If you upgrade to ECMlink V3 full, you can run this ground wire to one of the ECU inputs instead of your switch. You can then program ECMlink to activate the input according to whatever parameters you want. You can also toggle it on and off manually via the menu in ECMlink.

The wire you're looking for should be the GB wire on pin 1 of the 4 prong connector A-40 ---> http://www.dsmtuners.com/forums/153372392-post13.html.

Here's the diagram: http://www.galantvr4.org/docs/1g_circuit_diagram.pdf

Page 8-84 CRCUIT DIAGRAMS - Cooling Circuit
 
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Since the radiator's thermo sensor is what turns them on when engine is too hot (and only when the ignition switch is on), just wire a switch across it (but leave the thermo sensor still wired in). That way you have an override to force them on. When your switch is off they will operate normally. Also since one side of the thermo switch is already connected to ground (all black wire), one side of your switch should connect to the thermo's green/black wire and the other side of your switch to ground. On a 1g I'm told the thermo switch is at the bottom of the radiator (it's not the sensor on the thermostat housing).


YES! Thank you! This worked like a charm! And way easier than anything else I've read. I'm sersiously stoked!
 
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