http://www.aa1car.com/trouble-codes/codes_199.htm Both heater codes. If I remember rite both heater circuits are wired together. You probably have one green wire one white wire (thy are use for the 02 signal) and 2 black wires thy are used for the heater tap into both of them on should have 12 volts just after you turn a key on. One should have 0 volts.

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