Alternator wiring is messed up when i bought my truck 89 silverado 5.7liter 350. I need help with wiring and i'm not sure if its the right alternator.I Switched out alternator still wont hold a charge. HELP!!!

Get yourself a schematic for that vehicle.

something is shorting, make sure your hood is not touching positve side of battery, or battery is secured and not moving around and touching something

I assumed full size truck?


1989 Chevrolet Truck Stereo Radio Wiring Diagram

Car Radio Constant 12v+ Wire: Orange
Car Radio Switched 12v+ Wire: Yellow
Car Radio Ground Wire: Black
Car Radio Illumination Wire: Gray
Left Front Speaker Positive Wire (+): Tan
Left Front Speaker Negative Wire (-): Gray
Right Front Speaker Positive Wire (+): Light Green
Right Front Speaker Negative Wire (-): Dark Green
Left Rear Speaker Positive Wire (+): Brown
Left Rear Speaker Negative Wire (-): Yellow
Right Rear Speaker Positive Wire (+): Dark Blue
Right Rear Speaker Negative Wire (-): Light Blu

Check belt, as well as voltage of battery when sitting and turned off, and voltage when running. Running voltage should be higher, showing charging, if not have alternator tested. Most big parts places will test that for free I believe. Don't forget to clean all your connections well while your at it.

You didn't mention fuel filter in your list. That would be the first thing to change.

Try a new distributer cap and rotor button,these are notorious for wearing out the carbon pick-ups and leaving carbon tracks in the cap which messes up the fireing order.If that does'nt fix it try plugs and wires.

CODE 43 IS ELECTRONIC SPARK CONTROL -.KNOCK SENSOR.LOOKS LIKE ALTERNATOR NOT PUTTING OUT ENOUGH VOLTS TO CHARGE BATTERY.YOU NEED 13.5 TO 14.5 VOLTS.CHECK ALTERNATOR FUSE AND ELECTRICAL WIRES.MAKE SURE BELTS NOT SLIPPING.IF ALL IS GOOD.REMOVE ALTERNATOR.LET AUTO ZONE CHECK IT.TO MAKE SURE.TURN OFF RADIO BEFORE MOVING BATTERY CABLES.SO YOU WONT LOSE RADIO CODE.YOUR CAR IS NOT GOING TO RUN RIGHT IF THE ECM DONT RECEIVE 12 VOLTS OR 13 VOLTS.

I can help regarding the polarity on my GMC 2500 Van alternator....
Facing the rear of the alternator, the red wire attaches to the screw terminal on the left. The black (grd) attaches to the screw terminal on the right. The top has a connector with 2 spade terminals. - one (left tab) is the "r" or relay terminal and the right one is the 'f' or field terminal.

Does this help... Red on left and blk on right....
-Jim

These trucks do have a regulator. But most importantly check all of your grounds. One bad ground can mess up an entire electrical system. Especially the charge.