12V trigger for thermostat?

[BastardS4]

Any idea what wire i could use on the thermostat connector that would trigger my EFK?

Currently triggering off the AC fan but its pretty much on all the time this way. Id rather have it pop on and off when needed.

Tried off the unused fog light switch but no power to it.

[jaybquick@JHM]

Any idea what wire i could use on the thermostat connector that would trigger my EFK?

Currently triggering off the AC fan but its pretty much on all the time this way. Id rather have it pop on and off when needed.

Tried off the unused fog light switch but no power to it.

I am putting it in my FMIC vid on how to do it. But I do have the word doc that Mike @ VAST sent me a long time ago here --> http://jhmotorsports.com/tech/VAST_E...ied_by_JHM.doc

Read the side notes on page 3. Quite a simple hookup. That wire will switch to ground at 95c and when the A/C kicks on. Simple wiring on the relay. Been running around for over a year with it that way on my car and setup all my customers cars that way. All automatic and not ghetto like when you have to manually turn it on.

[BastardS4]

ha... i have that doc, but didnt read the notes carefully enough... hehehe could have saved me a vampire tap. :)

hmm. do they mean just put the #86 12V trigger line onto the thermostat wire?

Or put #86 to the 12V hot side, ground the negative terminal of the fan and use terminal 85 as the line to the thermostat?

[BastardS4]

and man.

two out of the three bolts holding the old fan clutch to the block were seized.

the one behind the pulley i got out just as the thing was rounding out, the other i had to hammer a T70 into. Thank god that one wasnt behind the pulley. Or it would have been drill time.

These DIY jobs were probably a lot easier when the cars had less than 80K on em. These days things are getting tougher.

[jaybquick@JHM]

ha... i have that doc, but didnt read the notes carefully enough... hehehe could have saved me a vampire tap. :)

hmm. do they mean just put the #86 12V trigger line onto the thermostat wire?

Or put #86 to the 12V hot side, ground the negative terminal of the fan and use terminal 85 as the line to the thermostat?

You hook terminal 86 to battery +. Then tap into the brown green wire and run that to Terminal 85. It switches to ground so you just need battery plus on 86 and allow it to ground to control the circuit.

and man.

two out of the three bolts holding the old fan clutch to the block were seized.

the one behind the pulley i got out just as the thing was rounding out, the other i had to hammer a T70 into. Thank god that one wasnt behind the pulley. Or it would have been drill time.

These DIY jobs were probably a lot easier when the cars had less than 80K on em. These days things are getting tougher.

Yeah I think it has to do with the snowy climate. I see California cars all the time with over 100k and we never have siezed bolts. The only cars that have bolt issues are cars that came from snowy states.

Yeah it is going to be tougher and tougher as they age, especially in snowy climates.

[BastardS4]

Yeah so i wired the sucker up as you and the diagram suggested. an as soon as i plugged the relay back into the pigtail harness, the damn afterrun coolant pump started running.

I thought i had done something wrong, so i yanked it back off. still running. pulled the terminal off the battery, put it back on, still running. Now i was getting worried, turned the ignition on and off, still running.

Now REALLY worried. Suddenly, stopped on its own.

Apperently i had wired everything just right, and for some reason this happens when you first connect it. Bloody bizzare.

Oh and it doesnt work as well as i had hoped, if the AC is on the damn fan runs just as it did when i had the trigger off the AC fan.

But apperently it will at least trigger with the AC off, and if the temp climbs above 95C or whatever.

I guess thats the best i can hope for. Ill tell you, that stupid pump coming on gave me that lovely sinking feeling of "what fucking 600$ part did I just short out?"

Needs a better writeup for sure.


PS mike and the boys say stop breaking your fans.

[jaybquick@JHM]

Yeah so i wired the sucker up as you and the diagram suggested. an as soon as i plugged the relay back into the pigtail harness, the damn afterrun coolant pump started running.

I thought i had done something wrong, so i yanked it back off. still running. pulled the terminal off the battery, put it back on, still running. Now i was getting worried, turned the ignition on and off, still running.

Now REALLY worried. Suddenly, stopped on its own.

Apperently i had wired everything just right, and for some reason this happens when you first connect it. Bloody bizzare.

Oh and it doesnt work as well as i had hoped, if the AC is on the damn fan runs just as it did when i had the trigger off the AC fan.

But apperently it will at least trigger with the AC off, and if the temp climbs above 95C or whatever.

I guess thats the best i can hope for. Ill tell you, that stupid pump coming on gave me that lovely sinking feeling of "what fucking 600$ part did I just short out?"

Needs a better writeup for sure.


PS mike and the boys say stop breaking your fans.

Yeah they always do that when you hook them up. The darn computer sees the relay and it temporarily back feeds the wire on that circuit. So the computer says turn pump on. So it is not a problem.


Sounds like you got it right. The fan will work when the A/C is on and also when the A/C is off above 95c. You need the airflow for A/C so the condensor gets enough airflow to work properly and doesn't overheat and cause the A/C high side pressure to get too high and trigger the cutoff switch and kick the A/C back off. Since your stock fan always ran, it would help with the A/C. Since you don't have that mechanical fan anymore you must have the hi flow fan running.


Only other option is some kind of aftermarket variable speed fan control unit. Look up "delta fan controller" online. They made some killer ones I would use with Mustangs, not sure if they are still around.

[BastardS4]

Ah well, ill get used to it I guess. Wonder if it will help with oil temps at all.


dunno why these DIY type mods never go smoothly for me.

[PhunkFX]

Do you guys ever notice any difference in how the car runs without the old stock fan clutch?

[Matt@JHM]

Do you guys ever notice any difference in how the car runs without the old stock fan clutch?

After we installed my FMIC and EFK I could definitely notice an increase of power. Although I'm sure 90% of that increase was from colder IATs.

[PhunkFX]

Right, nobody installs just the EFK alone haha. I am going to be doing that. Though I did have friends with the same cars, with the same exact mods, both stage 2+ except one had an EFK, and it was just quicker than the other for some reason... quicker than some stage 3 cars... It sounds trivial... and the car could have just been a freak or been running better... but it sounded logical to us. It seems like an engine efficiency factor.

[BastardS4]

Right, nobody installs just the EFK alone haha. .

I did. But my old clutch fan bearing was shot.

[PhunkFX]

I did. But my old clutch fan bearing was shot.

Mine doesnt sound so good either.

[BastardS4]

update.

good long run last night. no issues. oil temps seem to be down a tiche, and coolant temps rock solid.

Im running ER intercoolers so there is plenty of airflow in the first place.