4.9L Engines Only

Measure resistance between test pin No. 43 at the breakout box and battery positive side of the A/C cycle pressure switch.

If resistance are less than 5 ohms, EEC-IV system is not at fault. Repair or replace cycle pressure switch. If resistances are greater than 5 ohms, repair open circuit and remove breakout box. Reconnect all components and repeat QUICK TEST.