AllBay lights stopped working on 2006 Monterey Laguna IV

[David Stump]

Hey all!
I just had an electrical issue pop up and am wondering if someone might steer me in the right direction for troubleshooting.  Today I hit the master bay light switch at the entrance of the coach and the switch light up like normal.  Proceeded to the bays and found that none of the lights were working.  I am not sure of the correct procedure to troubleshoot the auto reset breakers in the electric bay.  Can anybody steer me in the right direction?  I put multimeter on the terminal for the bay lights and it read battery voltage.  There is another terminal on a strip to the far right in the bay also labeled bay lights and it too read battery voltage. For both of these tests I grounded to the metal strip on the bottom of bay between circuit breakers and the gang of 25 relays.  Not sure if this is correct procedure.  At first glance it seems that all is good in the electric bay so the trouble can't be far away if all are not working?  Also, just because the switch is lit does that mean is could still be bad?  Any nudge in the right direction will be greatly appreciated

[Joel Ashley]

Is your “salesman’s” switch on?  If it’s off, the bay lights might be one of the circuits it cuts, but I’m not sure you’d have power to the bay switch lamp.  And I haven’t had a chance to peruse the wiring diagram(s) for you yet.

Checking both sides of the bay lights switch for 12v would be a next move, but getting at the back of the switch may take some doing.

Joel

[David Stump]

Will double check that switch.  Everything in coach is working so pretty sure it is not that.  Also will pull switch plate off and see what bay switch looks like.  Do you know if the switch could be bad even if light on switch is on?

[Steve Huber Co-Admin]

David,
Switch is probably ok. I suspect you have a bad connection at a connector to the bay lights. I think the 12v is "daisychained" so if the connection at the first connector is bad, they all don't work. I'd look in the front 2 bays as they are closest the source.
Steve

[David Stump]

Thanks for the replies!  Did a more careful investigation today.
Tested circuit breaker.  Reads good battery voltage
Tested switch.  Is sending power to the appropriate wire behind panel.
Tested Terminal block on far left in elect. bay.  There is NO power there when switch on panel is engaged.

 I am not sure of the relationship between the terminal block and the circuit breakers but I suspect that I should be reading battery voltage there.  As a test I checked the terminal block for voltage for the (nearby) dock lights and it read 0 volts.  I then turned on the dock lights and it then read good battery voltage at the terminal block.  Any words of wisdom?

Also checked wiring as advised in all of the bays but nothing seemed damaged or amiss....

[Steve Huber Co-Admin]

David,
I'm a bit confused as to your terminal block locations. (Following refers to Coach Assist 2006 Monterey Wiring Diagrams, sheet 16). You should have voltage on the 2 posts on CB9, regardless of switch position. When switch is in On position you should have voltage on TB1, pin 11. TB1 is the first terminal block to your right (as you are looking at the bay) of the Circuit Breaker terminal strips (but not the right-most). If you don't have voltage there with the switch on there is an open between the switch and TB1, pin 11. There shouldn't be a fuse in line as the Thermal Circuit Breaker CB9 provides protection. However, I'd check any internal fuse panels (probably in bathroom or rear closet) just to be sure. TB1, pin 11 should have 2 or more wires on it, one from the switch and the other(s) to the bay lights. They are numbered and the one from the switch should have the same # as the one exiting the switch.
What terminal block/pin# do you not have voltage on? Your initial post said you did have voltage on the bay lights terminal (I'm assuming you were referring to TB1, pin 11).
Steve

[David Stump]

Steve,

I need to learn right from left.  I meant right side of bay, and it is indeed TB1, pin 11 that I checked, and there are two wires attached like you said. There is no power on TB1, pin 11 no matter what position switch is on.  Also, it is true that I have power on cb9 no matter what position switch is in.   My first post was in error, I must have been checking pin 12, the slideout, which always seems to have power on it.

So if I understand you correctly, there is an open between switch and TB1 pin11 and the switch.  So when I energize the bay light switch on the panel what exactly is happening?  What is the relationship between wire out from switch, the terminal block, the circuit breaker and the lights?  Am i sending power through the switch to the terminal block then through circuit breaker to the individual lights?  I appreciate your help!
 

[Steve Huber Co-Admin]

David,
CB9 supplies battery power to the switch at all times. (CB9 is a thermal circuit breaker that will open if it senses increased heat due to increased current flow caused by a short). When CB9 cools down it will close again). When you close the switch 12v is sent to TB1, pin 11 and from there to the bay lights via the other wire on it.

Check TB1-11 to be sure the crimp on the wire from the switch is tight by slightly tugging on the wire. It's also possible the switch is bad. Check to see if you have 12v at the switch output when it is on or remove the wire that goes to TB1-11 at the switch and touch it to the switch input pin where the 12v from CB9 comes in. If the bay lights come on, you have a bad switch. You can also simply use a wire to connect the switch input terminal to its output terminal to do this test.
Steve

[David Stump]

Steve
Excellent! great explanation.  I am starting to understand the concept behind electric bay lay out.  If I understand you completely...I now understand that the switch is powered by a properly working circuit breaker and that when switch is energized it sends power back to the terminal block then from the terminal block to the bay lights.  I understand that since there is no power at the terminal block that the problem must be somewhere between the circuit breaker to the switch and from the switch to the terminal block.  If i find power at the switch then I know we are good from CB to switch.  If i find power on opposite side of switch when it is on then obviously trouble is between switch and terminal block. 

So for future reference....I could jump battery power directly from circuit breaker to the terminal block and bay lights should work properly? 

[Fred Brooks]

   Dave,
You are well on your way to the joy of trouble shooting. Divide and conquer is fun! Fred

[Steve Huber Co-Admin]

David,
Yes, that would work but if lights come on it will only tell you that the circuit from TB1-11 to the bay lights is OK. You will still have to determine the cause of the problem between CB9 and TB1.
Steve

[David Stump]

Steve,

Yes, I understand that.  Just thinking that down the road if I have another issue somewhere that may help me narrow down a future problem.

Thanks again for your assistance.  I will update with solution when I find it!

David

[Joel Ashley]

David, I don’t see a Bay Lights fuse in the bathroom bunch, nor a relay identified in the electrical bay.  Wish I had more time to help track this down since we have similar rigs, but if you haven’t seen these images here before perhaps they’ll be of some help.

Joel

[David Stump]

Dave,

Thanks for the info.  I have an interesting (probably temporary) end to the story.  I was showing my wife my new found knowledge of the electric bay, explaining how the circuit worked.  Showed her how with the switch on or off I had power to the circuit breaker and none to TB1 pin 11.  Went on to tell her that if i jumped from CB9 directly to TB1 pin 11 I would be bypassing our trouble and the bay lights would work.  So far so good.....  So I jumped between those two and sure enough the bay lights lit up just fine.  Here is the kicker.... when I removed the jumper the lights stayed on.  "Well, that wasn't supposed to happen".  I went in and turned off bay lights switch off in the coach and lights went out.  Turned back on and lights on.  Repeated several times.  What the heck!!??  Pure guesswork leads me to believe I have a switch that is going bad.  All I can think of.  Most unsatisfying fix ever.  Thoughts?

Also.  You mentioned no relay for the bay lights.  My schematic does'nt show one either.  I wonder why the  porch light, which takes the same bulb, has its very own relay but the bay lights, all 9 of them, don't require a relay?

[Joel Ashley]

Yes, resistance somewhere.  Could be just a loose ground wire, or corrosion… things loosen up with time and vibration, and the inconsistent behavior is typical of such a malady.  The looseness may be at the switch or its internal rocker mechanics may be shot.  Check all ground connection nuts/buss screws for snugness and/or corrosion that may be resisting current flow.  Then consider removing the switch escutcheon to examine that switch. 

Others here may remember the brand and specifics for replacing it if you think it’s a rocker/contact mechanics issue.

Joel