Ls with 4wd wiring
 

Good morning all.
My LS swap is going on a 4x4 and am trying to figure the wiring for the 4low circuit.
The exam has a 4wd circuit and a axle switch. Pins 2 and 3

I can’t seem to find the schematic for a 2008 gen4 with e38 ECM/ 4l60e transfer case wiring.

Do they just need a ground? When in 4low? Not in 4low?
Do they need to have 12+?
Do I need both? Just 1? Which 1? Etc.

I have email Brendan at lt1swap but have not heard back.
What have you guys done?

Thanks

Re: Ls with 4wd wiring
 

Anyone?

Re: Ls with 4wd wiring
 

Cheers

Re: Ls with 4wd wiring
 

I assume you're basing this on lt1swap.com's e38 diagram.

He mentions that some models used those pins. If you look up the two RPO codes he mentions, they both refer to a vehicle with a manually shifted transfer case.

I have an alldata subscription for a 2010 Tahoe. It says that pins 2-8 are not used. Which stands to reason, since the tahoe would never have had a manual t-case.

I question if you need those pins, since they probably only re-calibrate the speedo and shift points while in low range, and who needs that?

If you have to use those pins, I'd find a friendly mechanics shop who has an unlimited alldata subscription. Tell alldata that you want to look at a very bare bones silverado 1500. And look for the transfer case wiring diagram.

Re: Ls with 4wd wiring
 

My swap is in a 4x4 so the ecm needs to know it’s in 4 low so it can adjust shifts and speed O

Re: Ls with 4wd wiring
 

What I meant, was speedometer doesn't matter in low range. At least, it never did for me. When I'm in low range, I'm more focused on not sliding this pickup full of firewood into that tree. I'm not watching the speedometer. Also, the shift points wouldn't change much. All the old autos shifted exactly the same whether in hi or low. That's why I questioned if you actually needed to get that info to the ecm.

Re: Ls with 4wd wiring
 

No Because i have the same problem 2wd and hi 4wd and auto work ok but not 4wd low range there is because the pcm send the signal throughout the network because the speed sensor is hard wired to the pcm not to the transfercase controller there's not hardwired from pcm to transfer controller im work with transfercase controller to found how i can get the signal with a can bus simulator to get what is it address on can bus network.

Re: Ls with 4wd wiring
 

The original transfer cases have a contact for 4low I think in the push button 4wd maybe to the BCM. My transfer case only has a Contact for 4x4 light. I was thinking of adding a contact to close when the shift lever is in 4 low. So I will have a 4x4 light and the ecm will know it’s in 4low. I understand you may not look at the speed o but that doesn’t mean I can’t have it wired fully.

Does the 4low terminal need 12+ or a ground when in 4low? Anyone know?

Re: Ls with 4wd wiring
 

According to my schematics pin 2 needs a ground in 4lo. Pin 3 is for the front axle actuator so you probably don't have that.

Re: Ls with 4wd wiring
 

Perfect. That’s what I needed to know. Ground in 4Low.
Thank you.