What was found
STARTER VALVE OPEN LIGHT ON AT ROTATION. LEFT PACK OFF. 3 ENGINE LIGHTS FLASHED DISCONNECTED CONNECTOR DP1202 AT START VALVE, START VALVE LIGHT STILL ON. DISCONNECTED FIREWALL CONNECTOR D30234 START VALVE STILL ON. REMOVED DEU-1 WITH DEU-2 STILL POWERED START VLV LIGHT STILL ON. REINSTALLED DEU-1. REMOVED DEU-2 WITH DEU-1 STILL POWERED START VLV LIGHT STILL ON. REINSTALLED DEU-2, REF AMM 31-62-21. REF WDM 80-11-11-1 PG1 CHECKED FOR CONTINUITY FROM PIN 38 ON D30234 TO GROUND HAD 2.2 OHMS, SHOULD BE OPEN. WENT TO REMOVE ACAU REF AMM 21-51-02 WHILE TOUCH LH ACAU SHORT ENT AWAY, SUSPECT K20 IN ACAU WIRE NOW SHOWS OPEN. REINSTALLED ACAU AND POWERED UP A/C START VLV NOW SHOWS CLOSED. REMOVED ACAU AND BOTH DEUS AND DID MERGER CHECKS FROM CONNECTOR DP1202 PIN 4TO K12 ON D3973B & D3975B & D458A PIN 5. NO SIGN OF SHORT. REINSTALLED BOTH DEUS REF AMM 31-62-21 & REPLACED LH ACAU REF AMM 21-51-02 DUE TO SUSPECTED BAD K20 RELAY, OPS CHECKS GOOD. ACP ENGINE RUN REF AMM 71-00-00-700-801-F00 START VLV INDICATION NORMAL. A/C OK FOR SERVICE.