DME 7.8 DME 7.8 0 · 0-77P0481

DME 7.8 DME 7.8 0 0-77P0481 495 Fan output stage 2 - open circuit Diagnosis conditions • Engine running • Battery voltage greater than 7 V • Medium pressure switch (air conditioning) active or engine tem- perature greater than 105 °C • Air conditioning switched on and off once Note! The triggering wire for relays stage 2, terminal 85, is monitored Possible fault cause ♦Open circuit ♦Relay faulty ♦DME control module faulty Affected terminals Terminal IV/20 Diagnosis/troubleshooting Work instruction Display OK If not OK 1 Check both relays ♦Remove relay Approx. 75 Ω Replace relay ⇒ Step 2 → End ♦Measure resistance between Pin 85 and Pin 86 2 Check wiring from DME ♦Connect special tool 9637 to Repair wiring har- control module, plug IV wiring harness (DME control ness Pin 20, to relays for conti- module plug) → End nuity ♦Remove relay stage 2 of coolant fan 1 ♦Remove relay stage 2 of coolant fan 2 ♦Measure resistance between 0 - 5 Ω special tool 9637 plug IV Pin 20 and relay slot of coolant fan 1 plug Pin 2 1908 P0481 0-77 page 1 Printed in Germany, 2000 p0481