> Mike Esh wrote: > Current readings are at Mono valve are as follows: > 12 volts when system is off.
The monovalve is not controlled with a steady voltage. 12V is switched on and off rapidly, called pulse width modulation. That is, the more heat requested, the longer the OFF pulse and the shorter the ON pulse. > System on any of the 3 center buttons pushed: > 12 volts when temp wheel is set to full cool or full heat. > zero volts when temp dial is moved to any other position. A DC volt meter is not a very dependable way to measure the control signal. The measured voltage will depend on the specs. of the meter. An oscilloscope is best. I suppose a ignition dwell meter would work. Do you have one of those? > Zero volts when defrost button is pushed. Defrost is the fail mode. So when there is no power to the monovalve, and no vacuum to the servos the system will be in full heat, defrost mode. So this point is correct. > Is this correct? Any suggestions? Without an oscilloscope - or maybe a dwell meter - swapping out parts may be the best option. I saw an hardware kit that will turn an iPad into a oscilloscope... -- Philip _______________________________________ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
