View Poll Results: Obs Cluster
Ls
0
0%
Gauge
0
0%
Cluster
0
0%
Voters: 0. You may not vote on this poll
OBS LS swap how to make gauge cluster work .
Thread Starter
Teching In
Joined: Mar 2021
Posts: 1
Likes: 0
OBS LS swap how to make gauge cluster work . Hello ,
Im currently in the process of gathering parts for my 6.0 swap into my 91 c1500 . I haven’t found much info on how to make the moon gauge cluster work . Does anyone have any info on how to make this work ? Im willing to pay for the info .
thanks
Im currently in the process of gathering parts for my 6.0 swap into my 91 c1500 . I haven’t found much info on how to make the moon gauge cluster work . Does anyone have any info on how to make this work ? Im willing to pay for the info .
thanks
Registered User
Joined: Dec 2024
Posts: 1
Likes: 0
I know this thread is 3yo but I wanted to help after my struggle! I found that the moon guages only work with the old vss wiring spliced in line with the ls swap vss sensor harness mine now works and its within 1mph accuracy
Last edited by kthompson1000007; Dec 10, 2024 at 08:50 PM.
Teching In
Joined: Jan 2026
Posts: 17
Likes: 1
Behold the answer to your question Alright, so having done my 6.0 lq4 swap in my 1990 k1500, this is all you need to know:
-Speedometer: Uses the VSS in your transfer case. (The VSS for your ECU is usefull if you have an automatic transmission (needs it to shift properly) or if you put an aftermarket or LS stock speedometer). If you're running a manual transmission you can discard the auto and VSS ECU plugs, but in all cases, you must plug in your old OBS VSS plug for the original speedometer.
-Tachometer: Tacho-who?
-Fuel meter: Works OEM - (BUT DONT FORGET: IT WONT WORK WITHOUT THE GROUND IN THE ENGINE BAY - DONT CUT IT, IT HAS OTHER INSTRUMENTAL GROUNDS ON IT).
-Voltimeter: Grounded and functions within the I/O panel, you can forget about it, it'll work.
-Temp: This ones the weirdest, but it's easy peasy. Basically on your 6.0, you have a temp sender (should be in your driver side head, but it could be over the 8th cylinder). This one speaks to your LS ECU. This one does not speak to your gauge and honestly don't try anything funky. Your 1990 cluster read temps using on singular wire on a temperature sensor. You must keep your old temp sensor and get an adapter on amazon that screw into the sender hole in the head. Basically you will have one temp sender on one side speaking to the LS ECU, and on the opposite side of the engine, theres a plugged threaded hole for the same sender where you will put the adapted OBS sensor. (LS heads are usually identical, but use one temp sender stock so the other side is plugged but functional. So you use one head normally for ECU and the other side for you old sensor for the cluster).
-Oil pressure: Also a little out of the ordinary, but simple: You just use your old OBS oil pressure sensor as the LS ECU doesn't need it and is also only cluster-bound. So again, amazon adapter, screw in where the LS one went, put the plug in. (PS: only one wire should remain. The 2 other wires were a fuelpump shut off switch in case of significant oil pressure loss. I mean you could still use it if wired properly, but cluster wise - it's only the middle wire that is required).
-Speedometer: Uses the VSS in your transfer case. (The VSS for your ECU is usefull if you have an automatic transmission (needs it to shift properly) or if you put an aftermarket or LS stock speedometer). If you're running a manual transmission you can discard the auto and VSS ECU plugs, but in all cases, you must plug in your old OBS VSS plug for the original speedometer.
-Tachometer: Tacho-who?
-Fuel meter: Works OEM - (BUT DONT FORGET: IT WONT WORK WITHOUT THE GROUND IN THE ENGINE BAY - DONT CUT IT, IT HAS OTHER INSTRUMENTAL GROUNDS ON IT).
-Voltimeter: Grounded and functions within the I/O panel, you can forget about it, it'll work.
-Temp: This ones the weirdest, but it's easy peasy. Basically on your 6.0, you have a temp sender (should be in your driver side head, but it could be over the 8th cylinder). This one speaks to your LS ECU. This one does not speak to your gauge and honestly don't try anything funky. Your 1990 cluster read temps using on singular wire on a temperature sensor. You must keep your old temp sensor and get an adapter on amazon that screw into the sender hole in the head. Basically you will have one temp sender on one side speaking to the LS ECU, and on the opposite side of the engine, theres a plugged threaded hole for the same sender where you will put the adapted OBS sensor. (LS heads are usually identical, but use one temp sender stock so the other side is plugged but functional. So you use one head normally for ECU and the other side for you old sensor for the cluster).
-Oil pressure: Also a little out of the ordinary, but simple: You just use your old OBS oil pressure sensor as the LS ECU doesn't need it and is also only cluster-bound. So again, amazon adapter, screw in where the LS one went, put the plug in. (PS: only one wire should remain. The 2 other wires were a fuelpump shut off switch in case of significant oil pressure loss. I mean you could still use it if wired properly, but cluster wise - it's only the middle wire that is required).