Hello All-

I am having prob. with my heater on 2000 S-type 3.0L. I have purged air from system, bench tested heater valve. It is testing OK; in other words, solenoids engage when voltage applied. Checking the wiring harness, I have live middle red wire whether or not car is on or heater is on. I have open circuit to outer 2 wires on either side of the red power wire. This leads me to believe there is a relay or other module/circuit interupting the feed back to the chassis ground. Your input is greatly appreciated. If relay, do you know where it would be located? My manual makes no mention of heater valve relay.

Thanks -

mtfife