Test U: Dual Generator Lower Fault Detected (P1148)

PINPOINT TEST U: DUAL GENERATOR LOWER FAULT DETECTED (P1148)

U1-U4:

U4-U6:

U6-U8:

Normal Operation
The generator output is determined by the voltage of the A circuit 35 (OG/LB). The A circuit voltage is compared to a set voltage internal to the voltage regulator and the voltage regulator controls the generator field current to maintain the correct generator output. The set voltage varies with temperature and is typically higher in cold temperatures and lower in warm temperatures.

Possible Causes
- Lower generator C1251a disconnected
- B+ circuit fusible links
- B+ circuit 2037 (RD) (lower) open
- A circuit 35 (OG/LB) open, short to ground, or high resistance
- I circuit 1185 (YE)/1183 (WH/YE) open or short to ground
- Lower generator