DIY mod: Aux Fan sensor and wirings

**miked** · January 25th, 2011 02:34 PM

present setup is 80 Watt aux fan does not come on when the temp rises to, let's say 100C. it comes on only when A/C is on.

got some electrical know-how (not that expert enough) and copied a wiring schematic for a cooling fan and is basically the same for all vehicles...temperature switch activates cooling fan via a relay and so on.

sorry no drawing but let me illustrate it "in words"..just use your imagination.
we have a control circuit and load circuit.
Control circuit: Batt + to inline fuse to control circuit of relay then manual switch then ground. got it? will use AWG 18 wire for this one.
Load circuit: Batt + to load circuit of relay to cooling fan then ground. will use AWG 10 wire here.

Here is my planned set-up and take note i will be using a single 80W fan to cool A/C condenser and engine coolant temperatures.

1. I will tap the radiator cooling circuit to the 80W A/C fan installed at present, since the addition of another fan is impossible due to space availability.
2. I will not tap to the "ON" of the starting switch. instead, i will tap at battery positive and put a dedicated switch at ground side for the radiator cooling circuit.
3. 80 watts / 12 volts = 6.667 amps say 7 amps draw by the fan. would a simple splice of a AWG 10 wire to the A/C circuit going to the cooling fan be enough?
4. judging from the amps value, a 30 amp 4pin or 5 pin relay will do.

anybody done this? comment please before the summer season kicks in. TIA

**gremz** · January 26th, 2011 01:55 PM

Originally Posted by miked

present setup is 80 Watt aux fan does not come on when the temp rises to, let's say 100C. it comes on only when A/C is on.
TIA

..tol,

di kaya busted lang yung thermo switch mo? ang therm0 switch kasi eh usualy between 80~85C, then yung thermostat naman eh nasa 82C. Compatible dapat yung thermo switch at thermostat ng radiator.

hope i can help

gremz

**jick.cejoco** · January 29th, 2011 05:50 PM

Originally Posted by miked

present setup is 80 Watt aux fan does not come on when the temp rises to, let's say 100C. it comes on only when A/C is on.

got some electrical know-how (not that expert enough) and copied a wiring schematic for a cooling fan and is basically the same for all vehicles...temperature switch activates cooling fan via a relay and so on.

sorry no drawing but let me illustrate it "in words"..just use your imagination.
we have a control circuit and load circuit.
Control circuit: Batt + to inline fuse to control circuit of relay then manual switch then ground. got it? will use AWG 18 wire for this one.
Load circuit: Batt + to load circuit of relay to cooling fan then ground. will use AWG 10 wire here.

Here is my planned set-up and take note i will be using a single 80W fan to cool A/C condenser and engine coolant temperatures.

1. I will tap the radiator cooling circuit to the 80W A/C fan installed at present, since the addition of another fan is impossible due to space availability.
2. I will not tap to the "ON" of the starting switch. instead, i will tap at battery positive and put a dedicated switch at ground side for the radiator cooling circuit.
3. 80 watts / 12 volts = 6.667 amps say 7 amps draw by the fan. would a simple splice of a AWG 10 wire to the A/C circuit going to the cooling fan be enough?
4. judging from the amps value, a 30 amp 4pin or 5 pin relay will do.

anybody done this? comment please before the summer season kicks in. TIA

please identify your vehicle. it might already have the infrastructure for what you intend to do

**miked** · January 31st, 2011 12:29 PM

Originally Posted by gremz

..tol,

di kaya busted lang yung thermo switch mo? ang therm0 switch kasi eh usualy between 80~85C, then yung thermostat naman eh nasa 82C. Compatible dapat yung thermo switch at thermostat ng radiator.

hope i can help

gremz

paps,

i have the Circuit Thermo Switch MB 660663. internet data says 80-85C range. my question is di naman kaya wala nang pahinga yung fan kung 82C tsat? thermostat was removed by previous owner and i want to put one back. 4d56 turbo. one manual says 76.5C and the other manual says 82C. confused a bit here.

to clear things up, there is no previous setup for the cooling fan circuit...i'm planning to add one.

thanks

**miked** · February 2nd, 2011 03:25 PM

What should be the best tstat-thermo switch combination then?

A. 82C tstat + 80-85 C thermo switch
B. 76.5C tstat + 80-85C thermo switch
C. 82C tstat + 90-95 C thermo switch
D. 76.5C tstat + 90-95C thermo switch

Present your answer in 3...2...1....time's up!

hehe..quiz contest na to!