Tom, The signal going to thru RPM relay is in the form of a pulse. You can see it on an oscilloscope, but if you don't have that just check the ohmage of the pulse coil which should be around 600 ohms cold. If that is there then the RPM relay should activate when you start cranking over the car. If you take the black or green box off the relay you would see and hear the relay inside open and close. Hope this helps. John Hervey -----Original Message----- From: dmcnews@xxxxxxxxxxxxxxx [mailto:dmcnews@xxxxxxxxxxxxxxx]On Behalf Of Tom Tait Sent: Saturday, July 02, 2005 4:17 PM To: dmcnews@xxxxxxxxxxxxxxx Subject: [DML] RPM Relay/ECM/Pulse generator Diagnostics Is there a procedure available to test the signal going to the RMP relay? Can the relay itself be tested with a 12 VDC power supply or do I need an alternating/pulsing current? To address comments privately to the moderating team, please address: moderators@xxxxxxxxxxx For more info on the list, tech articles, cars for sale see www.dmcnews.com To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnews Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/dmcnews/ <*> To unsubscribe from this group, send an email to: dmcnews-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/