Help with electrical problems

02 trailblazer with the blower motor not blowing and the e brake and the abs light is on. We had a bad battery and it ate up the positive connector so I changed the battery and the dealer changed the cables now they say they still have no idea what the problem is. They say it is throwing 23 codes so there is a communication problem and want to change the ignition switch first then the dmu or umd or cmu box, I don't know what they called it. Sounds like a lot of money with no promisses in sight. Any thoughts are appriciated.

TB's do some crazy things when the ignition switch goes bad, but you usually get a no-start condition along with it. Some vehicles will light up the E-brake and ABS lights when the alternator is not putting out enough juice & you will loose hi amp draw items like fans and blowers. Be sure to verify ~14VDC across the battery leads with a hand-held voltmeter on an idling truck. You cannot go by the dash gauge for this. Anything less than 14VDC on the truck at idle means something is up with the charging system.

G/luck
Joel

It was the ignition switch, thanks for the advise.