Wierd Dash and Lights

[pdub]

Hello gurus of Sunfire land, Im new here and joined to get some feedback on trying to fix my sons 2005 Sunfire. It currently has 111k miles and runs just like a top. Cant even feel the engine when its running. My problem is the dash gauges. When I instert the key the chime starts to alert me the key is in the ignition. Got it. When I turn the key to the run position it will either put all the lights on and they will go out as they pass the Power on self test. great so far. I can start the car and the gauges are just perfect. no failures. As soon as I step on the break pedal, I see both turn signal on dash just flicker as the break lights I assume come on. After I switch to Reverse, all the gauges light up (failures, trac loc, abs, check engine etc). At the same time the fuel gauge goes from full to completely empty as with the tach, the and the odometer goes to error. the only way to reset this state on the dash is to put the vehicle in park and actually turn the key as to almost engage the starter and I hear the stepper motors reset the gauges and then the problem is sometimes cleared. Im going to post a couple of pictures to help your trouble shooting. I have no idea what I can do: short in brakes, ignition switch, BCM, I guess I may actually have to go to the dealer, if I cant figure this out. its a great little car. your help is appreciated in advance. pat

 

[melsg5]

how about some background? Did you just get this car? if you did just get this car, any evidence of it being in an accident? any modifications to the car including a non-factory radio? have you had someone watch the brake lights to see if they come on and the correct lights come on, not the turn signal?

 

[pdub]

thank you for reply

I figured out the problem and glad it may help someone in the future. Un beknowst to me. My step son replaced the neg battery cable to fix the car" and I didn't notice that he failed to connect the battery box cable to the neg battery terminal. I ran a new wire from the neg terminal of the new cable on the the battery (neg) and hooked up to the chassis and sure enough the problem was solved. I had a feeling it was a floating ground and I knew it wasn't the instrument cluster. As soon as I pressed the brake pedal and no lights came on I knew I fixed it. Thank you for your reply and this may help someone in the future. The chassis ground is completely different from the Engine Ground and must be looked at when troubleshooting a problem with lights, gauges and such. Good luck with your Pontiacs. Pat

 

[melsg5]

thanks for the update