LQ9 swap...gauges dont work

[wesleyland]

Did a LQ9 swap into a 2000 silverado single cab. It originally had a v6. Engine is in and running good all sensors hooked up. But none of the gauges work, any suggestions or thoughts? isnt there a small module under dash?

[tfi racing]

What is your new harness out of?It may not be communicating with the BCM,that wire may have been missed.

[wesleyland]

wire harness is off of 2000-02 5.3 tahoe.

[kewljay223]

not sure how much i can help as i dont have the newer style gauges but what exactly do you mean they dont work? as in absolutely nothing is working or they just arent reading or not reading correctly?

im pretty sure you have a little lcd area for messages correct? does this light up? does anyting light up? do the gauges/lights do any kind of movement when you turn the key?

if nothing is happening at all i would assume you have no power to them. i would start with fuses and see if any are blown. if so then you may have connected a wire wrong somewhere. if fuses are good but still no power then maybe you forgot a wire to power them.

if you get lights and/or movement but the gauges just dont show readings then i would assume you have a problem with the cluster not communicating with the pcm/vcm/bcm so i would check those wires. i got you some diagrams from your truck that may help a bit.




looks like thae data lines i would start with to trace are the gray going to A5 lt grn going to C1 or the dk grn going to C4 since you said you had the 4.3.... hope this helps a bit. i can get you some other diagrams if you need.

[wesleyland]

yea my gauges light up, the message center flash battery and stuff but disappears. The LCD display that shows PRND12 doesnt light up though. Then the needles dont work.

[kewljay223]

sounds like data. like i said, try tracing those wires out maybe. or maybe one your control modules isnt getting power? you just gotta start tracing. but i would start with fuses first. easiest thing to get to and usually first place you should always start when diagnosing a non functioning electrical part.