1 Lower temperature Fan Relay Mod Wed May 07, 2014 1:57 am
wmax351
active member
Cross post from motobrick.com: http://www.motobrick.com/index.php?topic=5640.0
The title says it all. I it is very possible to modify the fan relay such that it activates the fan at a much lower temperature, perhaps even an adjustable one.
I will need to look at the other side of the relay board (I think I may have and extra one at home). Basically, the MC3302P is a standard quad comparator. It supplies +12v via a bias resistor for the coolant temperature sensor, and compares the voltage from in between the bias resistor and the CLT sensor, to one in between each of two pairs of resistors that are equivalent to the bias resistor/CLT sensor at 103 °C and 111 °C. These activate the fan and the idiot light, respectively.
I could alter the resistor for the fan switch, to set it to come on sooner, perhaps 95 °C. This would be a trivial modification to anyone with decent soldering skills. I can do them for people as well. I'll do the rest of this once finals are over next week, and post updates.
The title says it all. I it is very possible to modify the fan relay such that it activates the fan at a much lower temperature, perhaps even an adjustable one.
I will need to look at the other side of the relay board (I think I may have and extra one at home). Basically, the MC3302P is a standard quad comparator. It supplies +12v via a bias resistor for the coolant temperature sensor, and compares the voltage from in between the bias resistor and the CLT sensor, to one in between each of two pairs of resistors that are equivalent to the bias resistor/CLT sensor at 103 °C and 111 °C. These activate the fan and the idiot light, respectively.
I could alter the resistor for the fan switch, to set it to come on sooner, perhaps 95 °C. This would be a trivial modification to anyone with decent soldering skills. I can do them for people as well. I'll do the rest of this once finals are over next week, and post updates.
Last edited by wmax351 on Thu May 08, 2014 12:50 am; edited 1 time in total