GUARD AS 2840638 - Caterpillar

Illustration 1 g00722721
Rear view of the PRCM (1) 40-pin connector (2) Relay module
Table 1
Load Specifications For the Internal Relays of the PRCM    
Relay Module and Number     Ratings For Resistive Loads     Ratings For Inductive Loads    
"K1"     7 milliamperes to 1 Amperes (24 DCV)     None (1) (2) (3)    
"K2", "K3", "K4", "K5" (terminal 24), "K6" and "K7"     0.5 to 10 amperes (24 DCV)     0.5 to 10 Amperes (24 DCV) (3)    
"K5" (terminals 23 and 36)     0.5 to 10 Amperes (24 DCV) and 0.5 to 10 Amperes (24 ACV)     0.5 to 5 Amperes (24 DCV) and 0.5 to 7.5 Amperes (110 ACV)    
( 1 ) Do NOT connect inductive loads to these terminals.
( 2 ) The contacts of the relay that is connected to terminals 13 and 14 are gold flashed. The gold socket contact provides a source of low impedance for a low current resistive load. Loads that draw higher currents, currents that are of similar levels as terminals 23 and 36 in table 1 can be applied. However, if heavier loads are applied, the gold flashing will be permanently burned. This will eliminate the gold flashing from the contacts. This does not result in damage to the relay contacts, but the contacts can no longer be used for low current loads.
( 3 ) "K1" (terminals 13 and 14) is not fused.
Illustration 2 g00709866
The Connections for the PRCM to the Relay ModuleThe PRCM provides the internal relay outputs for customer's use. All relays are located in the relay module on the rear of the PRCM. If the CAT data link fails, the relay remains in the state required by the last valid input state. The relay may also be programmed to reset to the OFF position. Refer to Systems Operation, "Setpoint Viewing and Programming".The Possible cause of a CID 0478 FMI 04 is a short circuit of the "K2" relay coil. Clear the diagnostic code from the fault log when the troubleshooting procedure is completed.
Do not apply AC voltages to any relay module terminal other than terminals 23 and 36 of K5 and terminals 13 and 14 of K1 or permanent damage to the relay module will result. All other terminals have flyback diodes connected to them that increase relay life when driving inductive loads; however, this limits their use to DC voltages.
Note: All 3K-8782 Fuses ("AGC-10") in the relay module are rated at 10 Amperes DCV. Test Step 1. CHECK THE STATUS OF THE DIAGNOSTIC CODE.
Turn the ECS to the OFF/RESET position and then turn the ECS to the STOP position.
Press the "MODE" key until the diagnostic code viewing/clearing menu appears.
Observe the upper display. Check that the CID 0478 FMI 04 is active.Note: The "DIAG" indicator will be flashing and the CID 0478 FMI 04 will be present on the display if the diagnostic code is active.Expected Result:A CID 0478 FMI 04 is displayed as an active diagnostic code or the diagnostic code is inactive.Results:
OK