8206noco.fm Page 193 Thursday, July 2, 1998 1:19 PM
SYMPTOM RELATED DIAGNOSTICS ENGINE BRAKE VERBAL COMPLAINT (continued) Test 32
Test 34
Checking for voltage at the relay pin 30
Checking for an open wire or switch connection
Figure 312 — Voltage from Pin 30 to Ground
1. Reconnect the V-MAC II module connectors. 2. Turn the ignition key to the ON position. 3. Measure the voltage from pin 30 of the brake relay connector to a good ground.
If the voltage on pin 30 is approximately 12 volts, repeat the test for all the remaining engine brake relay connector. If all of the test results return to this step, proceed to Test 64. If the voltage on pin 30 is 0 volts, there is a short to ground or an open between the relay and the circuit breaker, or the circuit breaker has tripped. Find and repair the problem. Retest to be sure the problem has been corrected.
Figure 313 — Continuity between Pins 85 and 86 and the Relay Side of the Dash
1. Check for continuity between the relay side of the dash switch connector and pin 85 and 86 on the brake relay connector which had no continuity to ground.
If there is continuity, the switch connection was bad. Check the switch for good connections. Retest to be sure the problem has been corrected. If there is no continuity, the wire leading from the switch to the relay has an open. Locate and repair the open. Retest to be sure the problem has been corrected.
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