[InfiLights]

There are other threads that talk about this...but I think the answer is mixed into other thoughts....so here goes...

The merge switch activates a relay in the rear electrical panel.  Its purpose is to merge the house and engine batteries.  It needs to get power to do its thing.  That power can come from either the engine batteries or the house batteries.  The switch lets you choose between the two.  In one position, the power comes from the house battery, in the other from the engine battery.  I am not sure how your switch is wired so trial and error is the way to get it to work.

You may wonder why?  In one case, you leave the key on and kill the engine battery....you need to activate the merge using the house voltage.
In another case, you drain the house batteries by leaving TVs on over a long period.  In order to start charging the house batteries, you can merge with the engine batteries (hopefully with engine running)...obviously using the engine batter to operate solenoid.

Newell has recommended to me to leave the batteries merged all the time.  I cannot bring myself to do that.  I usually only merge if it is really, really cold outside and want some extra power to start the engine.

Finally, the merge solenoid is a known failure spot.  Newell recommends changing the solenoid on a regular basis (like annually or bi-annually).  The thinking is that we need to change the solenoid before it fails.

Hope this helps.
bill

Thank you Bill. I understand the logic of the merge and agree with the intended function.

My question is.....why does the switch have 3 toggle positions ?
In the middle position, the power comes from the house - all good.
In the down position it merges the house with the Chassis banks to aid starting and viceversa- solenoid engaged, all good working fine- banks merged.
In the up position .....can't seem to find it does anything ??? Am I missing something ?

This switch is like the Tag switch. in the middle is normal. push it in up position it air up the tag more and pushes it down to increase weight carrying capacity. Flip the switch now in the down position and it lifts the tag to make turning easier.......so , 3 way...

The Merge switch I am talking about is 3 way as well and the up position seems to do nothing....should it be a normal switch instead of the 3 way ?