[s-cars] 93 S4 heater issues

[Sam Clarkson]

Team
No heat, winter approaching here on the top side of the planet. I've  
pulled off and sucked on the vac line to the water tap and its moving/ 
working fine. There is good vac to the solenoid that controls the  
tap, even when the engine's been off for hours, so no vacuum issues.  
Can I swap that solenoid with the other one (what does it do) to  
test?. Can I test voltage to it, what readings am I looking for at  
hot and cold? What else?
Love you always


Sam Clarkson