W DOC AIRBUS | TSM A320F

Brake Fans Inoperative on All the Wheels

TASK 32-48-00-810-804-A
Brake Fans Inoperative on All the Wheels

1. Possible Causes
  • wiring between the BRK FAN pushbutton switch (4GS) pin A/B1 and the first terminal block
  • LGCIU-2 [5GA2]
  • wiring from the LGCIU2 (5GA2) pin AB/6F to the first terminal block
  • BRK FAN pushbutton switch (4GS)
  • wiring from the BRK FAN pushbutton switch (4GS) to the circuit breaker (3GS)
  • C/B-HYDRAULIC/BRK/FAN/CTL [3GS]
  • P/BSW-BRK FAN CONTROL (4GS)
  • CONTACTOR-BRK FAN,l (5GS)
  • CONTACTOR-BRK FAN,R (6GS)
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
AMM 32-31-71-000-001
Removal of the LGCIU
AMM 32-31-71-400-001
Installation of the LGCIU
AMM 32-48-00-710-001
Functional Test of The Brake Cooling System
ASM 324801
3. Fault Confirmation
Subtask 32-48-00-710-056-A ** ON A/C NOT FOR ALL
A. Test
   (1) Do the operational test of the brake cooling system AMM 32-48-00-710-001.
     (a) If the circuit breaker (3GS) trips:
  • Refer to Para. 4.A.(2).
   (2) Make sure that the fans do not operate on the four wheels.
4. Fault Isolation
Subtask 32-48-00-810-053-A ** ON A/C NOT FOR ALL
A. If the test confirms the fault:
  • Do a check of the circuit breaker (3GS) status:
   (1) If the circuit breaker (3GS) is closed:
  • Do a check for 28VDC at pin A/B1 of the BRK FAN pushbutton switch (4GS) (P/BSW (4GS) pushed) ASM 324801.
     (a) If there is 28VDC:
  • Do a check of the wiring between the BRK FAN pushbutton switch (4GS) pin A/B1 and the first terminal block ASM 324801.
       1 If there is no continuity:
  • Repair the related wiring.
       2 If there is continuity:
  • Do a check for a ground signal at pin AB/6F of the LGCIU2 (5GA2) ASM 324801.
         a If there is no ground signal:
         b If there is a ground signal:
  • Do a check and repair the wiring from the LGCIU2 (5GA2) pin AB/6F to the first terminal block ASM 324801.
     (b) If there is no 28VDC:
  • Replace the BRK FAN pushbutton switch (4GS).
       1 If the fault continues:
  • Do a check of the wiring from the BRK FAN pushbutton switch (4GS) to the circuit breaker (3GS) pin A/B3 to pin 2 ASM 324801.
         a If there is no continuity:
  • Repair the above related wiring.
         b If there is continuity:
  • Replace the C/B-HYDRAULIC/BRK/FAN/CTL [3GS] .
   (2) If the circuit breaker (3GS) is open:
  • Close it.
     (a) If it trips:
       1 If the fault continues:
  • Do a check for a short to ground at:
    . the wiring from the circuit breaker (3GS) to the BRK FAN pushbutton switch (4GS) pin 2 to pin A/B3
    . the wiring from the BRK FAN pushbutton switch (4GS) pin A/B1 to the first terminal block
    . the wiring from the LGCIU2 (5GA2) pin AB/6F to the first terminal block ASM 324801.
         a If there is a short to ground:
  • Repair the above related wiring.
         b If there is no short to ground:
  • Replace the C/B-HYDRAULIC/BRK/FAN/CTL [3GS] .
     (b) If the circuit breaker stays closed and if the fault continues:
  • Replace the P/BSW-BRK FAN CONTROL (4GS).
Subtask 32-48-00-710-057-A ** ON A/C NOT FOR ALL
B. Test
  • Do the test given in Para. 3.A.
[Rev.8 from Aug 2018] 2026.04.04 04:31:47 UTC
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