Power Steering Oil Pressure Switch

Fig. 4 Pressure Gauge & Ohmmeter Installation:

The following procedure require the following special tools to complete. An oil pressure gauge assembly tool No. MB990662-01, a power steering oil pressure gauge pump side adapter tool No. MB990993-01 and a power steering oil pressure gauge hose side adapter tool No. MB990994-01.
1. Disconnect pressure hose from oil pump then connect special tools as shown, Fig. 4.
2. Bleed air from system as outlined under MAINTENANCE PROCEDURES/BLEEDING SYSTEM, then turn steering wheel from stop to stop until fluid temperature in reservoir is 122-140°F.
3. Start engine and allow to idle.
4. Disconnect connector of pressure switch and place an ohmmeter in position.
5. Gradually close shutoff valve and increase hydraulic pressure and record pressure when switch activates.
6. Pressure should be 213-284 psi when switch activates.
7. Gradually open shutoff valve and decrease hydraulic pressure and record pressure when switch deactivates.
8. Pressure should be 100-171 psi when switch deactivates.
9. Replace switch if not as specified.
10. Remove special tools and bleed system.