Rolls Royce HVAC bad
Posted: 14 Apr 2020, 04:05
Hello hoping someone can help read hvac control unit ecu. (LITTLE BACK GROUND) Customer brought car blower motors not working, its been to 2 other shops before coming to me. Customer said first shop said hvac unit was bad sent in for repair and got lost in the mail. Second shop ordered a new hvac control unit and could not get it to work (would not give car back to customer for 2 weeks?) Finally customer brought it to me. Checked all wires and relays all ok, looked at the hvac unit plugs on the unit could be swapped which would send alternator voltage to ground pin. started checking components on the hvac unit found dead darlington array, ordered spare replaced but while replacing overheated and blew the capacitors, installed similar caps. relays started coming on and off stays on for a bit clicks off. found that old PIC16F74 (PLCC 44PIN) has 10ohm between vcc and vss. Orded new PIC16C74A installed rail voltage stays at 4.9 volts. But the board is not powering the relays now.
Ok is it possible to read PIC16f74 using Orange5 and transfer the data to the new PIC?
Thank you sorry for the long write up.
Ok is it possible to read PIC16f74 using Orange5 and transfer the data to the new PIC?
Thank you sorry for the long write up.