C5 Corvette Auto HVAC control moodule

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This page will help you repair the C5 automatic HVAC module. Electrolytic caps have a life span (very short if Chinese) MOSFET's go bad also. If the traces on the circuit board are burned, your motor may be pulling too much current. Some people have said you cant test the module out of the car. WRONG, you can. Some people have also said to test put voltage on the tan wire. DONT, This wire needs resistance, not voltage. See below for testing/ repair, info. I have fixed these units for $5 so give it a try.

 

Parts layout

If you have a soldering iron, know how to use one, buy the following parts from Mouser electronics

1. rectifier 863-mur1520g (1)

2. MOSFET 942-irf1010ezpbf (1)

3. 47 uf cap  598-476xm050m (1)

4. 4.7 uf cap 598-475ckr050m (1)

5. Cap 1200uf 35v 667-EEU-FC1V122B (2)

 

1. Using a 12vdc 3 amp power supply connect 12vdc to pin shown in top picture

2. Connect meter to blower pins, purple and black. Use a digital meter on dc volts, polarity does not matter

3. Connect resistor, 5k to 10k  to tan connector to neg on power supply. I used a pot.

4. Turn supply on and read volt meter, should be 12vdc.

 

The IC cant be sourced but is usually fine.

 use the ends of a clothes pin to get the clip back on semiconductors. then remove them with tweezers.