'85FC31 Security Light issue... update!

[James]

Thanks to all for the advice and I have an update on the issue as it
is not solely associated with just the security light switch.

1) I have narrowed the cause of the problem to just the front and rear
landing lights. I was incorrect in my original diagnosis when I said I
could toggle all of the lights individually. Driving lights and rear
parking lights toggle without issue. However, both the front and rear
lights trigger the issue.

2) To answer Jim's question, the issue occurs on battery power, when
using the generator and when plugged into shore power. All batteries
were replaced with mew Trojan T-105 in Nov '07. All individual
batteries check out with 6V+, system is 12V+ and the grounds are
solid. Even when I lose power, the batteries meter out a solid 12V+,
almost like they're isolated from the whole issue.

3) As Bill suggested, I tried removing the relay for the front landing
lights (both solenoid and relay located in the left rear load center
above driver's side bed), toggled the dash switch and lost power
throughout the coach again.

4) Gregory asked about the possibility of the issue being a duplicate
of the results from triggering the AT switch. However, the AT switch
does not kill the coach lighting system and I am able to start and
operate the engine without problem.

5) Here is a list of other things within the coach that work and don't
when the issue is triggered: Top two A/C packs are inoperative;
Water-pump is inop; Dash radio is inop; Microwave works; Engine,
headlights and driving lights work; Digitell works. Everything that
is inop when issue is at hand comes back to life when the system
"resets" itself.

6) The lights are OEM and were never upgraded to a brighter set.

I am not an electrician, nor did I sleep at a Holiday-Inn Express last
night. I can scan in my load center schematics if that would help
anyone who is.

The rear landing light solenoid and relay are located in the left,
front load center (mid-coach, over the driver's side couch, next to
the Master Electronics shut-off switch) which raises a question. The
chances of having two relays or two solenoids being bad at two
different load centers seem to be statistically very small.

Therefore, is there a common power feed to the landing light sets that
might be grounding? If so, where might it be? Basically, what is
causing the instant power kill and then the time delay before it
resets? Alternatively, where else could my Gremlin be living?

Thanks to everyone,
Please call me "JR"
'85FC31-SB aka: "The Short Bus"