Master Relay

[RV7Guy]

I'm helping my neighbor with this 7. He has the same engine, starter etc... We also have the EXP switch panels. I wired most of the plane and wired the Master Relay exactly as mine. When the Master switch is turned on we hear a click. On my plane when I hit the master switch I hear and pronounced "clunk" from the master relay. We don't hear that on his.

We are not getting power through the relay to the starter solenoid. Also the Master Relay is very warm to the touch.

I'm thinking the Master Relay is bad. Since there are only two wires to the Master Relay it is rather difficult to wire incorrectly. He wants to do a complete wire retrace and check. All continuity checks are good. I have suggested he tries another Master Relay.

Anyone have any other ideas?

[Gary Bricker]

Make sure you are getting 14V to the small connection that pulls the coil in that makes the two large battery cable connections connect.

[AltonD]

On the Van's master, you actuall ground the small connection on the relay. It gets its power from the battery side. Maybe, the EXP bus is not getting a good ground to the firewall.

[Rivethead]

When the small diameter terminal on the solenoid goes to ground the contactor becomes closed. Just connect a wire between that terminal and a ground point to test if the solenoid is working.

[MCA]

There's a document on our web site describing contactors that may be of help to you.

See Contactor Wiring doc on this page: http://www.verticalpower.com/documents.html

[647jc]

I don't have my plane or documentation close by but when you use an external Master Solenoid with the EXP unit you need to remove the onboard relay and replace it with a jumper device provided with the EXP unit. It's documented in the instructions. The small click you hear when you hit the master switch is probably the onboard relay that should be removed. I can't explain why your Master Solenoid is hot unless it is picked all the time. If it is picked, you should have power to your starter solenoid which you say you don't so you may have a bad master solenoid as you suspect. I'm only guessing here but I do know the EXP unit and Vans standard Master Solenoid will work together.