I am currently doing the wiring for a 6.0L LQ4 swap in a 2005 4x4 blazer (it had the 4.3 v6 before). The harness I am using doesn't include wiring for the fuel gauge and I would like to avoid repinning the PCM connectors if that is possible. I have the purple and black wires coming from the fuel sender assembly and the resistance reading is about 135 at half a tank of gas. Is there any way that I can use these wires to connect to the gauge directly? If not does anyone know which wires need to be connected to the PCM in order to get the stock fuel gauge working? Any help would be appreciated.

 

Purple goes to PCM connector C2, pin 54. Black goes to PCM connector C1, pin 23.


George

 

The instrument cluster gauges incuding speedometer are all stepper motors run by the PCM over a single communications wire. So no direct connection for any of them.

Here's someone who has done it.

https://blazerforum.com/forum/builds...-blazer-94742/

 

To expand on what George posted - that gets the fuel gauge signal to the PCM. To get it out of the PCM it needs to go through serial data to the instrument cluster. Here's the schematic for that (attached).

Better I think to get the specific pre-wired PCM and wiring harness like ChunkNTruck did.