Section 47.1
SPN 599/FMI 4

This diagnosis is typically both Cruise Control switches, SET and RES, are shorted to ground.‪

Section 47.1.1
Short to Ground Check

Check as follows:‪

1. Turn the ignition ON (key ON, engine OFF) and place the Cruise Control Switch in the OFF position. DO NOT start the engine.
2. Check the driver console display.
   1. If Cruise Control switch status RES is displayed, go to step 3 .
   2. If Cruise Control switch status SET is displayed, go to step 4 .
3. Unplug the RES Cruise Control Switch.
   1. If RES status is no longer displayed, replace the Cruise Control RES Switch. Refer to "47.1.1.1 Verify Repairs" .
   2. If RES status is still displayed, repair the short to ground in the wire from the RES switch to pin 16 of the CPC #1 connector. Refer to "47.1.1.1 Verify Repairs" .
4. Unplug the SET Cruise Control Switch.
   1. If SET status is no longer displayed, replace the Cruise Control SET Switch. Refer to "47.1.1.1 Verify Repairs" .
   2. If SET status is still displayed, repair the short to ground in the wire from the SET switch to pin 12 of the CPC #1 connector. Refer to "47.1.1.1 Verify Repairs" .

Section 47.1.1.1
Verify Repairs

Verify repairs as follows:‪

1. Turn ignition OFF.
2. Reconnect any electrical connections that were disconnected to perform the diagnosis.
3. Clear codes with DDDL 7.0 or latest version.
4. Start and bring engine up to operating temperature (over 140°F/60°C).
5. Verify operation is satisfactory and no warning lamps illuminate. If warning lamps illuminate, troubleshoot the codes. If assistance is required, call the Detroit Diesel Customer Support Center at 313–592–5800.