Bosch C1210ESC Technical Service Bulletin page 2

4 | A3 / E3 Error Code Troubleshooting
4. Remove control unit from heater and reseat wire connector on
circuit board:
a. Unplug heater's power cord.
b. Remove 3 screws attaching control unit to heater.
c. Turn control unit over.
d. Remove 6 screws attaching rear cover to control unit.
e. Remove rear cover.
f. Locate shorter of 2 multiple wire connectors on edge of
circuit board (Fig. 3, pos.1).
g. Remove and reinstall connector onto edge of board to
improve the electrical connection.
5. Ensure power cord is still unplugged or push power button to
"off" position. Disconnect jumper from connector and measure
resistance through jumper.
a. If less than 115 or greater than 125 ohms, jumper is faulty.
b. If between 115 and 125 ohms, contact Bosch Tech Support
for further instructions.
Data subject to change without notice | Printed in the USA | BTC 740002307 B | 06.2011
Figure 3
Technical Service Bulletin
Bosch Thermotechnology Corp.
50 Wentworth Avenue
Londonderry, NH 03053
Tel: 1-800-283-3787
Fax: 1-603-584-1687
www.bosch-climate.us
Bosch Thermotechnology Corp.