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radiator fans....

Posted: Mon Jul 09, 2007 5:30 pm
by lvlistchif
ok well im doing a srt-4 swap and im wondering with my radiator fans sence im going to be using the stock 2.0's im wondering instead of buying the adapter plug am i able to just plug a power and ground up to it and just always have it run or even throw in a toggle switch so i can turn it on and off and just not plug the harness in it? or does like the ecu need to be able to read that its there because something will go wrong if i dont? also im running megasquirt so ill already be throwing tons of codes as it is.

Posted: Mon Jul 09, 2007 6:01 pm
by Canada

Posted: Mon Jul 09, 2007 6:53 pm
by lvlistchif
thats how to run it after its already hooekd up im trying to do it so i dont even have to hook the wiring harness up thats so if the wiring harness is hooked up u can turn it on whenever u want and overrun the computer... i want it so the computer dosent even read it and its not plugged up to the harness.

Posted: Mon Jul 09, 2007 7:08 pm
by turbodudey
Why not just hook it up to the fan output from MS? Then you can program it to automatically switch on and off and whatever temp you want, and you don't have to remember to flip a switch.

Also, the PCM won't care at all if the fan is plugged in to it or not...

Posted: Mon Jul 09, 2007 7:48 pm
by lvlistchif
do i connect the MS to the power or ground on the radiator fan?

Posted: Mon Jul 09, 2007 7:50 pm
by Canada
Ground :lol:

Posted: Mon Jul 09, 2007 8:07 pm
by turbodudey
lvlistchif wrote:do i connect the MS to the power or ground on the radiator fan?
Ground. Always ground. Everything MS does is accomplished by grounding the circuit.

There are several ways to hook it up though. You can't ground the fan directly to MS, as it cannot handle that much current. You'll need to ground the fan control relays. There is a high output relay, a low output relay, and a control relay.

If you don't care about retaining the high/low feature of the fan, then you can just hardwire the fan to the control relay and then used MS to switch it on and off.

If you want to keep the high/low functionality, it would get slightly more complicated...

Posted: Mon Jul 09, 2007 8:15 pm
by lvlistchif
im confused on what you mean by the high low control relays... were are these at? in the fusebox? how do i even hook those up to the MS im so confused on what you just said by that


edit

i forgot to say that im using the stock 2.0 radiator/fans

Posted: Mon Jul 09, 2007 9:10 pm
by turbodudey
Ah. Oops.

The 2.4L has a two speed fan, but the 2.0L just has a single speed fan.

So, there are no high/low output relays to worry about then. :)

There is just one relay in the PDC that you would hook up to MS. All you do is wire the ground pin of the excitation coil in the relay to MS instead of the PCM.

Posted: Mon Jul 09, 2007 10:01 pm
by lvlistchif
ahhh ok i see another question is is the throttle position sensor the one on the top or bottom of the throttble body?

Posted: Tue Jul 10, 2007 1:17 pm
by turbodudey
lvlistchif wrote:ahhh ok i see another question is is the throttle position sensor the one on the top or bottom of the throttble body?
TPS is the only sensor on the TB.

It's on the side of the TB...