07-05-2015, 10:07 AM
Join Date: Sep 2014
Location: Santa Cruz
Total Cats: 0
so i can't just do this with the iac2 wire? i have to build a little transistor circuit?
IAC Spare Ports
The following IAC outputs are capable of driving over 0.5 Amp directly, sufficient for most automotive relays. You can connect to them using the IAC pins on the DB37 (25, 27, 29, and 31). Also, note that IAC1A and IAC1B are inverted relative to each other, as are IAC2A and IAC2B.
IAC1 - PT6,
IAC2 - PT7.
The IAC pins come out at:
(1A)JS0 to IAC1A - DB37 pin 25,
(1B)JS0 to IAC1B - DB37 pin 27,
(2A)JS0 to IAC2A - DB37 pin 29,
(2B)JS0 to IAC2B - DB37 pin 31,
Be sure to install a jumper from the hole marked S12C to the hole marked JS9 (+12C).
NOTE: PT6 (IAC1) and PT7 (IAC2) setting are reversed in MegaTune 2.25 (as of May 15, 2006), so PT6 in MegaTune actually affects IAC2, and vice versa. This will be corrected, so later versions of MegaTune may be correct. As always, you should TEST your configuration before using it in a car.
Also, after setting the second condition's value, you may have to hit the 'Tab' key to get the value to register.
The two spare port "T" pins (PT6 and PT7) are normally used to drive the stepper motor chip (IAC1,2). When you set pin PT6 high, it will make 1 of the 4 stepper output pins high and the other low, and no effect on the last two - which are controlled in the same way by pin PT7. So, by picking 2 of the 4 IAC outputs, you have two 12V spare pins that will directly drive about 0.5 Amps with no transistor needed. This is more than enough to drive a relay directly. If you are going to use port PT6 or PT7 as spares (IAC1,2), be sure not to set the idle control algorithm to any of the stepper control options (''IAC Stepper Moving Only', 'IAC Stepper Always On', or '15 Minute IAC'). This will keep the the stepper chip 'always enabled' and not turn it on and off, which would prevent the port from working as intended.