View Single Post
Old 03-14-2019, 12:57 PM   #11
FAKKY
Registered User
 
Join Date: Sep 2016
Location: Redington Beach
Posts: 1,312
Re: Depinned engine harness --- now ... ??

Quote:
Originally Posted by e015475 View Post
You're making this way too complicated.

To turn on the fan to cool the engine, the PCM grounds a external relay based on a temp selected in the PCM tune.

The trinary switch can also ground the same relay when the head pressure gets too high and the fan needs to come on to cool the ac condenser and bring the pressure down.

The fan shouldn't run all the time. It should be modulating the temp in the radiator as required, or be on when the head pressure is high in the ac. The fans shouldn't be running at highway speeds at all, and if they are, it can be an impediment to cooling.

You can disable the PCM stuff in HPTuners and shove a temp bulb into the radiator (or a thermo switch as shown in your drawing) for a stand alone control and wire your trinary switch to ground pin 85, but why when you have HPTuners? It's like killing ants with a hammer - it works but it isn't a very elegant solution and it is just another system to fail.
I know - Ive been accused of that a few times before. I think its just how my brain works (or doesnt). Pretty sure ls1nova71 said exact same thing in my last post he responded in.

So basically ....... if I have it [now].

1) Delete FAN 2 in PCM as I dont have it.
2) Use wire 42 on C1 to ground the relay to activate FAN based on engine temps input from PCM.
3) From the AC system - use a trinary switch. The 3rd wire will also ground to active FAN if AC pressure gets to high.

that it ?
__________________
FAKKY 57 PANEL BUILD
FAKKY is offline   Reply With Quote