Ford Workshop Manuals
E 150 V8-4.6L SOHC VIN W (2004)
Engine, Cooling and Exhaust > Cooling System > Heater Core > Component Information > Technical Service Bulletins > Customer Interest for Heater Core: > 06-21-19 > Oct > 06 > A/C - Heater Core Electrolysis/Leakage > Page 3471
Voltage less than or equal to 0.4 V OK
If greater than 0.4 V, turn off one item at a time until V drops to less than or equal to 0.4 V. Repair ground to the accessory just identified.
Recheck voltage less than or equal to 0.4 V
Turn the DVOM to AC volts.
Check for ANY AC voltage greater than 0.4.
If any AC voltage is present then try turning off each accessory one at a time including blower motor and any fan motors.
If AC voltage is still present then shut engine off and remove B+ from the alternator and tape it up then retest.
If voltage drop is gradual to less than or equal to 0.4 V, the ground straps may simply be overloaded by added accessories. Test by using
If vehicle is equipped with electric cooling fans, be sure they cycle during this testing and monitor voltage when they are on and when off.
DO NOT GROUND HEATER CORE. IF THE HEATER CORE IS GROUNDED, YOU HAVE PROVIDED THE ELECTROLOSIS A PATH
Refill the engine cooling system, reference Workshop Manual, Section 303-03.
IF THE HEAT OUTPUT IS INSUFFICIENT, OR THE ENGINE DOES NOT REACH NORMAL OPERATING TEMPERATURES, VERIFY
WARRANTY STATUS: Eligible Under Provisions Of New Vehicle Limited Warranty Coverage
BASIC PART NO.
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