Hazards not working when battery switch set to dual...

[harwoodr]

So, as the subject says - the hazards only flash when the battery switch is in the middle position (not dual and not mom of course), otherwise they just come on solid.  The turn signals work just fine.

I've looked at the wiring diagram for the 78s, but I can't find anything in there to do with the battery switch.  I guess that's because the diagram is for the chassis itself...

My wiring looks a little scary, but I may have to start tracing things to figure this out... unless anyone has a quick answer or has experienced this?

[Oz]

Very odd. Headlights, taillights turn signals and clearance markers are all part of the chassis electrical system. The mom switch just controls the linking of chassis and coach batteries. It sounds like a short between a wire from the mom switch against a turn signal circuit wire?

[Mlw]

This really is not to difficult. You sir, probably have another grounding problem . This said, Oz gives you a valueable tip about the short, but this means your PO was a wiring magician like mine was. Let's not go there yet an pretend the wiring is original 

The relays for the turn signals and the hazards are two different ones, so find your hazard relay and start there.

That you experience the problems by connecting the DUAL/MOM switch isn't very weird because the dual switch works on ground only controlling 2 relays.
Relay 1 connects your chassis and coach battery so both are charged by the alternator. (DUAL)
Relay 2 connects the batteries together for emergency starting. (MOM)

Because we are talking high current connections here the live wires of both batteries are connected to the live connections of the relay. Now to engage the magnet of the relay to connect the two batteries together you need the ground wire. To control this you need the dual switch. It really is as simple as that.

By engaging your dual switch you create a better ground but not to your blinkers. Let's not dig in this to deeply because it only creates confusion but because there is high resistance in your hazard ground  the electricity is going to flow the way of the least resistance, in this case created by engaging you dual switch resulting in dull flashing lights. Now as you say the turn signals work fine (with or without the dual switch engaged) you need to dig into the ground connection/wire of your hazard relay to your blinkers. If the grounding wire/connections aren'tthe problem then you need to check your hazard relay.


When your PO was a wiring magician.

https://www.classicwinnebagos.com/forum/index.php?topic=16254.0
https://www.classicwinnebagos.com/forum/index.php?topic=16311.0


An EXCELLENT explanation of the Winnebago coach electrical system by Dave:
http://dave78chieftain.com/ConverterInfo.html