2001 xtreme with a 5.7 vortec from an 2002 Express 1500 (and it's computer). Quick question, where does the purple gas gauge wire go to from the tank? And what wire goes to the gauge itself? I have the wiring diagrams, but it only shows the power feeds for the gauges. So sender to compute to gauge? When the battery was out for a couple weeks, the fuel gauge needle pegged itself pointing straight down first start up. So took the cluster out and spun the needle and it sat at 3/4 till I started it and moved and now stuck on E. And the low fuel light is on all the time. So the stepper motor is doing something. The other gauges work. I truly hate wiring on new cars... Thanks for any input.

 

I don't have a wiring schematic for the 5.7L computer but when your Blazer was stock, the purple wire goes into the "fuel level signal in" pin on the engine computer. The computer then aggregates that data along with other gauge functions and sends the info as serial data on the class 2 serial data bus to the IPC. The IPC then breaks up this serial data stream and drives the gauges.


George

 

Thanks for a direction to go in. Got half dozen trouble codes I'm working on, 2 are easy cam timing and abs speed sensor. Some I'll have to do more research U1000, U1016, U1096 and U1064. I'm the type to rip everything out and put a carb on it...
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Got it working, there was no wire going into pin 54 red on the pcm. Used a little jumper from pin 54 to the old sending unit resister, then other end of the sender to ground, gauge went near full float up all the way. Now just have to track down the purple 54 wire or just rewire it. Read another post saying it's comes up from underneath the brake booster from under the dash. Anyone reads this in the future, first find out what computer (and what it came out of), mine is the 0411l Scanner helps to id, either model or vin number. Pin 54 purple goes to the fuel sending unit, pin 38 purple goes to the gauge. Thanks again.

 

That carb refit is gonna make more codes. lol.


George

 

Looks like you have problems with the Class 2 CAN/J1850 bus.

That carb refit is gonna make more codes. lol.


George