LS swap into a GMT400

[tefzel]

Hi guys,

i have swapped a 6.2 L into my GMT 400 suburban.
i bought an aftermarket harness .

i am facing some issues with the harness output wires - the 1996 gauges don't read them, thus i don't have - oil pressure, temp , tech , speedometer , error signals .'

here are the ways i was thinking of solving this :
replacing the LS engine sending units to the old ones - doesn't help tech , speed and signals
putting a double sending units - doesn't help tech ,speed and signals
putting the original dash cluster from the 2011 Denali -i don't know if it works
buying a digital dash - expensive
finding an electrical adapter that reads LS PCM and "translate" t 1996 gauges

please share your experience

Thanks

 

[Gnasty1521]

I found all of the wires to the into from the old harness except coolant temp and oil pressure.

I used a 3 wire temp sensor with the new green lead going to the old gauge.

For oil pressure I used the old sensor with a brass adapter, obviously the gauge will still read and 40 is still excellent on the LS.

Sent from my Pixel 2 XL using Tapatalk

 

[brianmcb]

I did same as that guy above me. Gmt400 oil psi sensor with an adapter, and a 98 camaro 3 wire temp sensor.
I made the harness myself out of the ls harness, took some poking around with a meter to find where to tie into the tach, speedo, and check engine light

95 rcsb, L33 5.3, hot cam, frost tune, 5spd, 4/6

 

[Steve A]

Check LT1Swap.com for wiring diagrams and tips about aftermarket harnesses.

 

[Gnasty1521]

I used current performance for mine, then guess and check for hooking it all up.

Wiring it yourself would be a huge undertaking if this is your first time.

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[vr1967]

It is only about 10 wires that need to be added to the original Vortec harness and a few plugs (and the 2 80 pin connectors) that need changed.

Then just some time to re route / clean up the harness

 

[Supercharged111]

OP what transmission did you go with?