MSefi.com read only forum (Jan.15,2018)

I'm about to wire an electrical fan to my ms2 v3 ecu, I don't use an idle stepper valve, so i'm thinking of using the FIdle wire to the fan , and ground the other terminal of the fan to the car chassis, or to the sensor ground, which one is better ???
And does it work ?

FIDLE will supply ground to turn on a relay, but you must use a relay to control the fan as they need a lot of startup current.

Do not ground a fan to the sensor ground under any circumstances. They can be grounded to the chassis or engine block.

Matt Cramer wrote:FIDLE will supply ground to turn on a relay, but you must use a relay to control the fan as they need a lot of startup current.

Do not ground a fan to the sensor ground under any circumstances. They can be grounded to the chassis or engine block.

Thanks for the info mate, yeah i forgot to mention about the relay, my question was just about the ground...
By the way, my sensor ground is on the engine block 15 cm next to the megasquirt ground both in the engine block

Matt Cramer wrote:FIDLE will supply ground to turn on a relay, but you must use a relay to control the fan as they need a lot of startup current.

Do not ground a fan to the sensor ground under any circumstances. They can be grounded to the chassis or engine block.

Then, how to wire the fan and the FIDLE cable to the relay, i mean i thought that the FIDLE was the positive and the fan ground the negative...
Can you clarify to me how to wire things to the relay( the bosch 4 pin one, i.e where every pin goes...), as i'm a newbie with this ...
Thanks

Matt Cramer wrote:FIDLE will supply ground to turn on a relay, but you must use a relay to control the fan as they need a lot of startup current.

Do not ground a fan to the sensor ground under any circumstances. They can be grounded to the chassis or engine block.

+1, can the megasquirt case touch the car's chassis or it must be insulated by using plastic screws?

dochka wrote:

Matt Cramer wrote:FIDLE will supply ground to turn on a relay, but you must use a relay to control the fan as they need a lot of startup current.

Do not ground a fan to the sensor ground under any circumstances. They can be grounded to the chassis or engine block.

Then, how to wire the fan and the FIDLE cable to the relay, i mean i thought that the FIDLE was the positive and the fan ground the negative...
Can you clarify to me how to wire things to the relay( the bosch 4 pin one, i.e where every pin goes...), as i'm a newbie with this ...
Thanks

Can i run a wire directly from the battery(12v), the FIdle as (-) to the relay empowering(coil symbol), and the 2 fan wires to the relay(interuptor)?

Google "relay wiring" and it will give you a generic diagram how relays are wired.\it is important that the 12v supply to the relay comes from the megasquirt power relay(eg fuel pump relay,main relay etc) as if it does not it can cause feedback which causes problems(i made this mistake and the engine would not turn off when the fan was running)Steve.