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Wiring up a "tow haul" switch and using it as a drop gear button..

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Old 08-03-2012, 10:15 PM
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Default Wiring up a "tow haul" switch and using it as a drop gear button..

The truck scene does this a lot by making their tow haul switches a drop gear button for rolls...

on LS swaps i've used a momentary switch grounded to pin 71 on the blue connector...


any of you guys run a setup like this?
Old 08-04-2012, 05:51 AM
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Yep, shifts late, no clutch, more line pressure at low tps.
When I toggle it and the cutout it gets real loud.
Old 08-04-2012, 01:56 PM
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Originally Posted by greenvortec97

on LS swaps i've used a momentary switch grounded to pin 71 on the blue connector...

what is pin 71 ? I cant find any info on it.
Old 08-04-2012, 06:05 PM
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Empty slot in an f-body pcm, put a wire in it hooked to a switch
for momentary ground and you can use the performance trans tables
after it is enabled in the tune.
Old 08-04-2012, 09:25 PM
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Is that input for "tow/haul" mode specifically ?
Old 08-05-2012, 10:04 AM
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the way we always did it was setup erase the Tow haul transmission table and start with a Drop Gear one from scratch... doing it this way avoided having to manually drop a gear by the shifter.. The way the tables are setup are so that the PCM knows what gear to drop down to depending on what speed you're going.. 30 roll drops you down to first and so on..

it's pin 71 on the blue connector for the PCM. you wire up a momentary switch and have your tuner adjust the "performance" table for a drop gear table

i have a write up on it on a few sites.. here is the more detailed one.
Old 08-05-2012, 10:05 AM
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Originally Posted by oange ss
Is that input for "tow/haul" mode specifically ?
I've heard with a custom EFI live OS you can do much more than transmission tables.. Such as two separate tunes but i'm not too familiar with EFI live
Old 08-06-2012, 02:18 PM
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Would this work on my LSx swapped mustang? Because this would be fantastic!

What I would like is running 55 mph, hit the button, and bang, 2nd gear WOT powah to the ground. Or am I missing something?
Old 08-10-2012, 07:56 PM
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You got it bro, same thing as a downshift only with a button
Old 11-26-2012, 04:02 PM
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finally got around to doing this, it works and it helps alot with racing against m6 guys or any other manual transmission car. all you do is hit the button, give it a little bit more pedal, and the trans will downshift and hold the rpm until the pcm sees a 100% tps reading
Old 04-04-2020, 05:04 PM
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Originally Posted by greenvortec97
the way we always did it was setup erase the Tow haul transmission table and start with a Drop Gear one from scratch... doing it this way avoided having to manually drop a gear by the shifter.. The way the tables are setup are so that the PCM knows what gear to drop down to depending on what speed you're going.. 30 roll drops you down to first and so on..

it's pin 71 on the blue connector for the PCM. you wire up a momentary switch and have your tuner adjust the "performance" table for a drop gear table

i have a write up on it on a few sites.. here is the more detailed one.
Waking this post from the dead!!!

Tried to click the link and it doesnt work. Any info on how to do this or a link that works?
Old 06-20-2020, 10:00 AM
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Originally Posted by Nick Rutledge
Waking this post from the dead!!!

Tried to click the link and it doesnt work. Any info on how to do this or a link that works?

i used google to find several write ups
Old 06-21-2020, 11:46 AM
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Originally Posted by Nick Rutledge
Waking this post from the dead!!!

Tried to click the link and it doesnt work. Any info on how to do this or a link that works?
Here is one
https://ls1tech.com/forums/conversio...thout-bcm.html



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