cooling fan switch

[Marks04DSG]

Couple questions about the cooling fan switch mod. ( new to me)

1) Can it be used anytime you feel like you need more fan (even while drriving?) Will control be given back to pcu when switch is turned off without messing any of the ecu fan settings up?

2) Does using it effect in anyway the thermostat or flow of coolant?

3) When the switch is used what speed will it be (the high or low)

Thanks

[Angus66]

Originally Posted by Marks04DSG

Couple questions about the cooling fan switch mod. ( new to me)

1) Can it be used anytime you feel like you need more fan (even while drriving?) Will control be given back to pcu when switch is turned off without messing any of the ecu fan settings up?

2) Does using it effect in anyway the thermostat or flow of coolant?

3) When the switch is used what speed will it be (the high or low)

Thanks

YES

NO

HIGH

[Marks04DSG]

Originally Posted by Angus66

YES

NO

HIGH

Thanks Angus, just got my *** reemed for 14.00 on a foglite switch for the project, what the hay it's worth it for those real hot days (and track if I ever make it there)

[machery]

What is the mod? I went the route of installing a relay in the low speed wire with a switch on the dash. I used a relay to interupt the circuit when I turn on the switch, as not to back-feed any current into the ecu when I have my switch in the on position.

[Marks04DSG]

Originally Posted by machery

What is the mod? I went the route of installing a relay in the low speed wire with a switch on the dash. I used a relay to interupt the circuit when I turn on the switch, as not to back-feed any current into the ecu when I have my switch in the on position.

I just wanted to install the optional switch to turn the cooling fan on for extra cooling like at the track in between runs or just for extreme heatsoaked days, So are you saying we need to wire in a relay also so it doesn't feedback current into the ecu? Could you put it in simple terms please

The post I read about doing this mod referred to the hi-speed wire I think, don't remeber reading about a relay though?? Just said to wire in an inline 1/2 amp fuse to ground is all. Not doing the electric wp yet, just the hi-speed fan switch.

[hawk]

If you wire in a switch like I've seen referenced for this mod, (http://www.svtcobraclub.com/TechAppl...fan_switch.pdf)
All you are doing is grounding the PCM signal to the CCRM for the high-speed line. That is the same thing the PCM does. You are not back-feeding any current to the PCM.

I checked out the schematic for ours, and yes, the wire you want is the Light green with violet stripe, coming off pin 46 of the main PCM connector (C175).

Grounding that wire will engage the high speed fan relay regardless of the PCM signal. So wire a switch from that lead to ground.

You can turn the switch "on" and the fan will run at high speed as long as the ignition is turned to "run". If the switch is "off", the PCM again controls the fan.

Sounds like machery is doing something different, since he is using the low speed circuit.

[machery]

Originally Posted by hawk

If you wire in a switch like I've seen referenced for this mod, (http://www.svtcobraclub.com/TechAppl...fan_switch.pdf)
All you are doing is grounding the PCM signal to the CCRM for the high-speed line. That is the same thing the PCM does. You are not back-feeding any current to the PCM.

I checked out the schematic for ours, and yes, the wire you want is the Light green with violet stripe, coming off pin 46 of the main PCM connector (C175).

Grounding that wire will engage the high speed fan relay regardless of the PCM signal. So wire a switch from that lead to ground.

You can turn the switch "on" and the fan will run at high speed as long as the ignition is turned to "run". If the switch is "off", the PCM again controls the fan.

Sounds like machery is doing something different, since he is using the low speed circuit.

Hey fellows, I'll explain later today when I get home from work!

[machery]

OK, I did not know about the trick of switching the wire from the main harness at the time, so I just simply installed a heavy duty relay into the low speed circuit of the fan (just before the large resistor mounted at the top passenger side of the fan housing). I think it was the red wire. I fed the relay (Normally open terminal) with a #10 wire and 30 amp fuse holder from the main post on the fuse block in the engine compartment. The wire to the fan went to the common terminal on the relay and the feed from the ecu went to the normally closed terminal. As far as the other 2 terminals on the relay which operate the relay coil, one gets grounded, and the other goes to a on/off switch. The other teminal on the switch gets hooked up to the fuse box inside the car. I hooked it to the accesory side of the fuse box so that the key at least has to be in for it to work. There I can manually turn it on with the electric water pump at the track for quick cooling when the engine is not running. I chose the low speed so that it is less current draw on the battery, especially while the engine is not running. I will admit that the other method is 10 times easier and requires a lot less wiring. If someone knows what wire in the ecu harness activates the low speed on the fan, I would like to know.

[machery]

Originally Posted by hawk

If you wire in a switch like I've seen referenced for this mod, (http://www.svtcobraclub.com/TechAppl...fan_switch.pdf)
All you are doing is grounding the PCM signal to the CCRM for the high-speed line. That is the same thing the PCM does. You are not back-feeding any current to the PCM.

I checked out the schematic for ours, and yes, the wire you want is the Light green with violet stripe, coming off pin 46 of the main PCM connector (C175).

Grounding that wire will engage the high speed fan relay regardless of the PCM signal. So wire a switch from that lead to ground.

You can turn the switch "on" and the fan will run at high speed as long as the ignition is turned to "run". If the switch is "off", the PCM again controls the fan.

Sounds like machery is doing something different, since he is using the low speed circuit.

does this mod work when the key is turned to the accesory position, such as for running the fan while the engine is not running like at the track for cool-down between runs? or does the key have to be in the ignition position? Need to know!

[YellowMenace]

The key has to be on

[macher03]

I'm not a gearhead, and I did the mod with little effort and expense. FOLLOW THE DIRECTIONS. Just be careful with that &*#) little wire when stripping it. The mod works great!

[3150Mach1]

Originally Posted by macher03

I'm not a gearhead, and I did the mod with little effort and expense. FOLLOW THE DIRECTIONS. Just be careful with that &*#) little wire when stripping it. The mod works great!

I agree, I did the Hawk mod as well. I used a tap for the ecu wire so did not have to strip. Second time I was into the ecu. First time was the Nitrous window switch.

[97on22s]

does it make any difference in performance running it in staging??

or after you run?