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Lq4 with 4l80e question

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Old Nov 18, 2020 | 10:06 PM
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Default Lq4 with 4l80e question

Working on completing my wiring for my 02 lq4 6 l conversion mated to a 4l80e. I've looked at a lot of DIY wiring tutorials feel pretty comfortable with what I'm doing but I have a question that no one seems to want to answer/or is unaware of actual operation. I want to run an aftermarket – cluster from Dakota digital in my 84 Caprice, the HDX series to be more specific. That instrument cluster has a nice gear indicator display in the center of the instrument cluster. Most of the DIY wiring tutorials say to remove most wires from the bigger of the two connectors on the PRNDL switch leaving the black wire. I want to complete this wiring loom with as least issues as possible and as complete as possible leaving a clean install. Do it once and get it right.
My main question is Dakota digital has a can bus adapter that will pull almost all info off an OBD2 connector to display on the dash without necessities like adding second sensors to the engine.

How does the LS ecu gather the information to decipher what gear the transmission is in? Is the information coming from the valve body or the PRNDL switch or a combination of both?

Setup:
6.0l Lq4 2002 ecm#12200411
4L80E Later version with rear cooler line connection.
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Old Nov 18, 2020 | 10:54 PM
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I could be wrong, but I think your going to need a Dakota Digital DSS unit.

DSS Unit

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Old Nov 18, 2020 | 10:57 PM
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Per the instructions page 13 for your dash...



GEAR (1 wire) The GEAR terminal is used for the gear shift indicator. The indicator is built into every system, but will not light up unless a Dakota Digital GSS gear shift sending unit is connected, telling the system what gear the transmission is in. The gear shift sending unit is not included with the system and must be purchased separately if desired. A BIM-01-x may also be able to provide gear indication if the vehicle has a compatible ECM and transmission. The GEAR terminal will connect to the FIRST terminal on a GSS-1000 or to the 1-WIRE terminal on a GSS-2000 and higher. Follow the instructions in the GSS manual for use with a single wire display system. When the gear shift sending unit is connected the gear indicator will be shown on the Home Screen. If a different Group Screen is being shown the gear position will light up temporarily any time the gear position changes.
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Old Nov 19, 2020 | 11:00 AM
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I have the HDX with the 4l80e and stock harness in my Nova. I plugged everything in like normal using the BIM module as well and everything works as it should, Shift indicator works perfect and I never bought the gear indicator from Dakota. Only sensor I had to install on engine was the oil pressure.
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Old Nov 19, 2020 | 12:14 PM
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Originally Posted by BillyFargon
I have the HDX with the 4l80e and stock harness in my Nova. I plugged everything in like normal using the BIM module as well and everything works as it should, Shift indicator works perfect and I never bought the gear indicator from Dakota. Only sensor I had to install on engine was the oil pressure.
Gear position is then coming over OBD. Does your PRNDL or neutral safety switch have one or two connectors. If it has two connectors, are you using all of the wires on the larger connector?
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Old Nov 19, 2020 | 01:21 PM
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I didn't use the external neutral safety switch on either of my LS swaps and the HP Tuners scanner is still able to see the position of the gear selector.
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Old Nov 19, 2020 | 01:40 PM
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Originally Posted by Ray Miller
Gear position is then coming over OBD. Does your PRNDL or neutral safety switch have one or two connectors. If it has two connectors, are you using all of the wires on the larger connector?
I'm not using the neutral safety switch.
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Old Nov 19, 2020 | 02:10 PM
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Originally Posted by BillyFargon
I'm not using the neutral safety switch.
Just so I understand, you are not using the PRNDL or "neutral safety switch" mounted on the driverside of the 4l80e transmission but are still receiving the gear selector position via OBD to the Dakota digital HDX instrument cluster? Sorry to break it down like that, just want to make sure.
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Old Nov 19, 2020 | 03:18 PM
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Originally Posted by Ray Miller
Just so I understand, you are not using the PRNDL or "neutral safety switch" mounted on the driverside of the 4l80e transmission but are still receiving the gear selector position via OBD to the Dakota digital HDX instrument cluster? Sorry to break it down like that, just want to make sure.
My transmission still has the factory electronics on drivers side of trans using the factory harness (probably why it works). I am not running any additional gear indicator from Dakota. I do not have the neutral safety wired up. I am only using the "BIM" module from Dakota.
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Old Nov 19, 2020 | 03:24 PM
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Originally Posted by BillyFargon
My transmission still has the factory electronics on drivers side of trans using the factory harness (probably why it works). I am not running any additional gear indicator from Dakota. I do not have the neutral safety wired up. I am only using the "BIM" module from Dakota.
That helps heaps....just going to leave the wiring harness alone that runs to transmission and will not "thin it out". I appreciate all that help, one less worry in my already busy head.
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