ROD A 0768269 - Caterpillar

September 9, 2001
U-243
A-164
before or
after failure PRODUCT SUPPORT PROGRAM FOR REPLACING THE 1894920 RELAY TIMER USED IN THE HYDRAULIC FILTER BYPASS CIRCUIT ON CERTAIN 420D AND 430D BACKHOE LOADERS
1408 5068 PS40690 This Program can be administered either before or after failure. In either case the decision whether to apply the Program is made by the dealer. When reporting the repair, use "PS40690" as the Part number and "7755" as the Group Number. If adminstered before failure, use "56" as the Warranty Claim Description Code and use "T" as the SIMS Description Code. If adminstered after failure, use "96" as the Warranty Claim Description Code and use "Z" as the SIMS Description Code.
The information supplied in this service letter may not be valid after the termination date of this program. Do not perform the work outlined in this Service Letter after the termination date without first contacting your Caterpillar product analyst.
TERMINATION DATE
September 30, 2002
PROBLEM
The 1894920 Relay timer used in the hydraulic filter bypass circuit needs to be replaced on certain 420D and 430D Backhoe Loaders equipped with the ?Deluxe Cab? option. The 1894920 Relay timer is used in the hydraulic filter bypass circuit to eliminate hydraulic pulses from activating the plugged filter warning lamp. Early D series machines built with the 1849738 Cab Group - Deluxe may have a defective relay, which causes the circuit to work incorrectly. The defective relay does not allow the relay to switch to ground and illuminate the warning (alert) indicator should the hydraulic filter get clogged.
AFFECTED PRODUCT
420D BLN1-1650
FDP1-2606
430D BNK1-0915
BML1-1070
PARTS NEEDED
1 - 1894920 Relay Timer
ACTION REQUIRED
***** Parts Stock *****
Remove all 1894920 Relay Timers not stamped with a Revision 3 (Rev 3) or higher from parts stock. If no change or revision level is indicated on the relay, it should be considered defective.
***** Affected Product *****
Check to see if the machine has this attachment by turning the key switch to the "ON" position to see how many warning lamps (alert indicators) on the side instrument panel illuminate. If the machine has 7 lights and is in the serial number range, it needs a new relay. If the machine has 4 indicators, it is not affected. Turn the key switch off.
This rework affects machines with cabs only. Machines with canopies are not included in this program.
Replace the relay by loosening the 5 - 9X2045 Fasteners (Torx T30) which secure the 1678283 Side Instrument Panel to obtain access to the wiring underneath.
Locate the 1894920 Relay. It is connected to the electrical system with a 1944414 Harness, which has 4 wires (G423 pink, 200 black, 113 orange and 455 brown). It may be necessary to remove the 1846430 Cover to gain access to the relay.
Install a new 1894920 Relay. Make sure that the new relay has a "Rev 3" or higher stamped on it. If no change or revision level is indicated on the relay, it should be considered defective.
SERVICE CLAIM ALLOWANCES
***** Parts Stock *****
Submit one claim for all 1894920 Relay Timers not stamped