tow haul
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
So does this come on when it's pushed and go off when it's pushed again? I have the tow/haul hooked up on my '71 and looked into the latching relay thing, but couldn't get it to turn off when the button was pushed again.
Yes you can use the button to turn it on and off or it'll shut off when you turn off the ignition.
The root problem with a swap - in my humble opinion - is there is no way to know Tow Haul is truly active without the BCM or reading the data bus directly.
Building a latching relay setup that counts the button pushes as mentioned above is cool, but if it gets out of synch for some reason it isn't accurate. Still cool though.
Building a latching relay setup that counts the button pushes as mentioned above is cool, but if it gets out of synch for some reason it isn't accurate. Still cool though.
Idont want to hijack this thread so I made a tut on how I did mine. this also addresses the problem of it not latching. I have used it over 100 times this summer trying new shift points and it worked every time. https://ls1tech.com/forums/conversio...l#post19126277
I bought this,
http://www.ebay.com/itm/Bistable-Flip-Flop-Latch-Switch-Circuit-Module-Button-Trigger-Power-off-Memory-/201412532274?hash=item2ee51f5832
It uses a momentary negative to activate a relay, that momentary negative will also trigger the tow/haul mode on pin 71. the relay will activate a led. When power is removed, the ecm will go into non tow/haul mode and the relay will turn off.
I have not connected it to the car yet. But I fell it will work just fine. Plus it was $6
http://www.ebay.com/itm/Bistable-Flip-Flop-Latch-Switch-Circuit-Module-Button-Trigger-Power-off-Memory-/201412532274?hash=item2ee51f5832
It uses a momentary negative to activate a relay, that momentary negative will also trigger the tow/haul mode on pin 71. the relay will activate a led. When power is removed, the ecm will go into non tow/haul mode and the relay will turn off.
I have not connected it to the car yet. But I fell it will work just fine. Plus it was $6
Thread Starter
On The Tree
Joined: May 2012
Posts: 133
Likes: 1
ok - so I am working on my third truck harness
i personally pulled the pcms and harness from the trucks and know they had tow haul because i purposely checked
having said that - this is the third harness where Blue pin 71 has never been used meaning it never had a pin in it before- yet I am told here that Blue pin 71 is the right pin to use
how can that be when one of the original, already used pins has to be the tow haul pin
what am I missing? what pin did the factory use for tow haul and why are we not re-using it? or is this another one of those BCM deals which will prevent reusing tow haul without wiring in a BCM
these are 2003 and 2004 pcms and harnesses for vans/trucks blue green pcms
from what I have been googling - B-71 only works on red blue pcms
next question - we will be using 2002 programing as EFI Live COS files require that operating system to work properly
By switching to the 2002 programing - will that allow the use of pin 71?
thanks
i personally pulled the pcms and harness from the trucks and know they had tow haul because i purposely checked
having said that - this is the third harness where Blue pin 71 has never been used meaning it never had a pin in it before- yet I am told here that Blue pin 71 is the right pin to use
how can that be when one of the original, already used pins has to be the tow haul pin
what am I missing? what pin did the factory use for tow haul and why are we not re-using it? or is this another one of those BCM deals which will prevent reusing tow haul without wiring in a BCM
these are 2003 and 2004 pcms and harnesses for vans/trucks blue green pcms
from what I have been googling - B-71 only works on red blue pcms
next question - we will be using 2002 programing as EFI Live COS files require that operating system to work properly
By switching to the 2002 programing - will that allow the use of pin 71?
thanks
Last edited by Seeker1056; Feb 17, 2016 at 07:38 PM.
It firms the shifts, holds gears a little longer and keeps it from going into overdrive until you're at a higher speed. Pretty sure it can all be changed in the tune to be more aggressive, but this is what they do stock.