Operation CHARM: Car repair manuals for everyone.
Home >> Chevrolet >> 2008 >> Impala V8-5.3L >> Repair and Diagnosis >> Technical Service Bulletins >> Customer Interest >> Cooling System - MIL ON DTC P0480/P0481 (Police Veh) >> Correction >> Part # 1

Part # 1

A revised engine cooling fan relay and harness assembly has been released, to reposition the cooling fan relays for increased air circulation.

1. Turn OFF the ignition, all electrical components, lamps, accessories and the scan tool.
Open the hood.





2. Remove the RH front fender upper diagonal brace bolts (1). Release the retainer that secures the wiring harness from the bottom of the brace (2), then remove the upper diagonal brace.
3. Loosen the negative battery cable terminal nut and remove the battery cable terminal from the battery. Refer to Battery Negative Cable Disconnection and Connection in SI.
4. Open the positive battery cable terminal cover, loosen the battery cable terminal nut and remove the battery cable terminal from the battery.





5. Remove the battery insulator.





6. Remove the battery hold down bolt and the hold down.

Note
Do not tip the battery more than 40 degrees during removal.

7. Remove the battery.
8. Release the inner RH headlamp retainer by pulling the retainer upward.
9. Remove the RH headlamp assembly bolt.
10. Pull the headlamp from the outboard edge in order to release the lock pin from the fender flange retainer.
11. Disconnect the electrical connector before removing the headlamp from the vehicle.





12. Remove the fuse block underhood electrical center cover (1).





Note
Observe the positions and orientations of the forward lamp battery supply harness terminal and the fusible links on the studs before removing.

13. At the top of the fuse block disconnect the two fasteners on the fuse block battery studs and remove the forward lamp battery supply harness terminal and the fusible links. Remove the fasteners (1) securing the electrical center board (2).
14. Unlock the tabs on the electrical center board, then evenly lift up on the board in order to remove it.





15. In the illustration above observe the orientation of the schematic for the fuse block. Identify the location of connectors X1 and X3.

16. Locate and mark for reference, the following circuit terminals:

- Connector X1, Circuit 473, 0.35 D-BU, Pin C7, High Speed Cooling Fan Relay Control
- Connector X1, Circuit 335, 0.35 D-GN, Pin H7, Low Speed Cooling Fan Relay Control





17. Locate and mark for reference, the following circuit terminals:

- Connector X3, Circuit 409, 3 L-BU, Pin D1, Cooling Fan - Right Supply Voltage
- Connector X3, Circuit 532, 3 GY, Pin E1, Cooling Fan - Left Low Reference
- Connector X3, Circuit 504, 3 WH, Pin F2, Cooling Fan - Left Supply Voltage





18. Remove both fuse block engine harness connectors X1 (1) and X3 (2) from their respective cavities.

1. Release and remove the bottom cover on both connectors.








2. Examine the X3 connector pins (1) and connector wiring (1) for evidence of overheating as shown.

^ If evidence of overheating is observed, continue with this repair.
^ If evidence of overheating is not observed refer to the appropriate DTCs in Engine Cooling or Symptoms - Engine Cooling in SI.





19. Position a ruler on the top of the upper radiator support (2) as shown. Align the ruler with the arrows (1) and mark the 165 mm (6.5 in) area with a paint stick or suitable marker.





1. Position the inboard edge of the cooling fan relay bracket (3) that was supplied with the revised harness assembly, 22 mm (0.86 in) from the outboard edge of the RH engine mount strut and tightly against the back edge of the radiator support.

Note
Align/adjust the ends of the bracket (3) over the radiator (2) slightly if necessary so that the holes in the bracket DO NOT sit over any spot welds (1).

2. Mark the location of the holes in the bracket on the upper radiator support. Drill the holes using a 5 mm (3/16 in) drill bit.

20. Secure the bracket and relay assembly to the radiator core support using the rivets that were supplied.
21. Remove the screw from the top of the windshield washer solvent container filler neck at the RF fender flange in order to provide additional clearance for routing the revised harness.





22. Route the revised harness (1) out from the engine compartment through the opening.

Note
Route the maxi fuse leads one at a time through the fender flange opening.

Route the harness back into the engine compartment between the windshield washer solvent container filler neck (2) and the RF fender flange.





23. Verify the proper routing of the harness as shown.





24. Using a suitable tool, open the engine harness conduit (3) for the X1 connector approximately 100 mm (4 in) from the entry point at the fuse block and extract the:

- High Speed Cooling Fan Relay Control Circuit
- Low Speed Cooling Fan Relay Control Circuit





25. Using a suitable tool, open the engine harness conduit (4) for the X3 connector approximately 100 mm (4 in) from the entry point at the fuse block and extract the:

- Cooling Fan - Right Supply Voltage Circuit
- Cooling Fan - Left Low Reference Circuit
- Cooling Fan - Left Supply Voltage Circuit

Important
Examine the cooling fan supply voltage and low reference circuit wires for discoloration, loss of insulation and brittleness in order to determine a good point to cut and splice.

26. When performing the following steps, adjust the location of the cuts at least 40 mm (1.5 in) apart in order to allow the splices to lay end to end.

1. Cut both of the fan supply voltage circuits approximately 100 mm (4 in) from the entry point at the fuse block or at a point where the insulation and flexibility of the wire appear normal.
2. Cut the fan low reference circuit approximately 100 mm (4 in) from the entry point at the fuse block or at a point where the insulation and flexibility of the wire appear normal.
3. Cut both of the fan relay control circuits approximately 100 mm (4 in) from the entry point at the fuse block.

27. Strip approximately 7.5 mm (0.313 in) of insulation from each of the five wires to be spliced.

1. Do not nick or cut any of the strands. Inspect the stripped wire for nicks or cut strands.
2. If the wire is damaged, repeat this procedure after removing the damaged section.

Note
Adding heat shrink tubing to the wire before splicing is advised in order to protect the integrity of the DuraSeal splices.

28. Compress handles until the ratchet mechanism automatically opens the J-38125-8 Splice Crimp Tool. Place a green DuraSeal splice sleeve in nest (1) as indicated above. Position the sleeve so that the crimp falls midway between the end of the barrel and the stop. Close the tool handles slightly in order to firmly hold the splice sleeve in the proper nest (1).





29. Insert the D-BU High Speed Cooling Fan Relay Control circuit wire (1) into the barrel (2) of the splice sleeve until the wire hits the barrel stop (3).





30. Compress handles until the ratchet mechanism automatically releases in order to obtain a secure crimp.
31. Repeat steps 29 and 30 for the opposite end of the splice.





32. Use a heat torch to apply heat to the center area of the sleeve while rotating and gradually moving to the open ends of the tubing. The tubing will shrink completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinkage has occurred.
33. Repeat steps 28 through 32 for the D-GN Low Speed Cooling Fan Relay Control Circuit wire.

Note
Adding heat shrink tubing to the wire before splicing is advised in order to protect the integrity of the Dura Seal splices.
pro multis · About Operation CHARM