tow/haul mode?

[THEFERMANATOR]

What are others doing as far as tow/haul mode on engine swaps? I know GM hooked the switch to the BCM and then transmits it over the class 2 data bus to the ECM or TCM to engage it it. Has anybody found a way to engage it without the BCM? Is there a simulator or something out there that will act as the BCM? I have everything worked out on my DURAMAX/allison swap except for this roadblock and I am trying to get past it.

[THEFERMANATOR]

Does anybody know of any companies out there that can make a box that can simulate a class 2 data bus signal to mimic what the BCM would send to engage tow/haul? I've found one, but it is pretty pricey and I don't know if it would interface with my ECM and FICM.

[THEFERMANATOR]

I finally got it to work, and was able to get an indicator as well. After some fiddling I got the BCM wired correctyly and it engages tow/haul just fine.

[joecar]

Good job... ...I was following along, but I didn't know any answers.

[dbunyip]

Do you have any info on how you got this to work?

[THEFERMANATOR]

I ended up wiring in the BCM and it's power and ground circuits. Hooked in a momentary switch to ground and installed a resistor in the PASSLOCK side. I also took my old cluster and cut the logic module out of it and hooked it up to an LED to have an indicator for tow/haul mode.

[Cougar281]

If you where to run a 01-02 TCM OS, you could run a momentary contact button to the TCM and a LED, and do without the TCM....

[THEFERMANATOR]

On an 01 you use the momentary to the TCM for overdrive lockout, but you still need the BCM for tow/haul mode no matter what year ALLISON your working with.