Can anyone tell me what the ground wires at the back of the drivers side head on a 90 LB9 are for? Two years ago when I did my head rebuild these 2 ground wires broke and I had to repair them. About 3 weeks after I got it all back together I've had stumbling problems. Two weeks ago my car started throwing code 43. It did this several times so last Tuesday I replaced the Knock sensor. Saturday night it threw a code 43 again just after the car became very sluggish. A mechanic friend of mine said it might be a bad ground. Also, I had to replace the Alternator(The old one cracked) and now when I touch the brake pedal all of the lights in the car dim? My battery is a delco, the green light on it is black but it still starts the car. Could this dimming issue be the signs of a weak battery?I checked the ground wires and they are in tact? How would I tell if they are bad or not?

 

You might want to see if one of those wires was a brown one that leads to the ESC.

The battery, I'd have tested somewhere that does it for free (i.e. Autozone, etc...) and make sure you have a good battery to chassis ground.