GM Repair Problems? Ask GM Repair Expert Now.
Hello and thank you for using JustAnswer. My name is David and I will do my best to help you with your GMC problem.Did new fuel pump module come with a sending unit?
yes it was a oem module
Is fuel gauge inoperative with both the old and new sending unit?Did you have to replace the connector that goes to top of fuel tank module?
fuel gauge worked fine the the pcm B fuse blew and the pump stopped working I replace the module with a oem module the the gas gauge was not working so i put the old sending unit on the new module but it did the same thing. no i did not replace the connector that plugs into the module
so i have to drop the tank?
i have replaced all the stepper motors. could the fuel pump have burrned up something when it blew?
i have a new programmed pcm the harness to the tank looks good. can a fuel pump burn up the pcm?
so almost everytime i start the truck it will go to 1/8 to 1/2 tank of gas for 20 sec then drop to E and the low fuel light will turn on .....I restart the truck same thing .. ok so set the ohm meter to like 200k and check the reading across the purple and black wire? what are the wires at the pcm?
Yea, read at the tank module, then at the PCM with tank connector plugged in.The black wire is at PCM connector C1, pin 23The purple wire is at PCM connector C1, pin 54PCM connector C1 (blue)PCM connector C2
Yea, reading across the black and purple. If you are reading at the wires, make sure the connector is plugged in. 200 ohm setting would be best. Tank sending unit ranges from 0 - 90 ohms.
ok let me pull the cluster and swap the stepper moter
ok I got it. the plug on the new oem module was bad. I put the old plug in the new module and everything works. It was making a connection (hence the good ohm reading) but not good enough to support the gas gauge.
thanks for all your help.
Thanks for the update.