
Originally Posted by
jojiesal
One side of the relay coil is connected in series with the thermostat, a/c switch, and fan motor speed control switch. The common terminal of the fan motor switch is grounded and there is a + 12v ignition switched connection going to the fan motor, the thermostat and the a/c switch which all seems fine. However, I traced the other side of the relay coil going to a small black box labeled WL81 located under the glove box compartment of my 2002 2.9L XL ranger. I don't know what exactly this box is for but it contains a small printed circuit board about the size of a cigarette pack. Is this an engine control unit and could this be the source of my problem. Could anyone tell me what this black box is?
Is there a reputable auto a/c electrical shop that could readily analyze my problem and not do guesswork on my a/c problem.