37A00-1 Troubleshooting


New Member
Hi All,
I recently bought a house which has an old OmniPro II (circa 2003) installed and have been slowly resurrecting it. This forum has been invaluable for this hobby and I sincerely thank everyone here who has provided content and answers over the years!
The light switches in the house used to run on an X10 network, but many had failed over the years so I have been slowly replacing with UPB switches. So far, everything has worked really well and setup has been a breeze. I do all of my configuration through PC Access (dealer edition).
However, I've now started upgrading the 3-way switches and ran into some seemingly odd behavior. Each 3-way has 1 Leviton 35A00-1 600W Dimmer and 1 Leviton 37A00-1 Aux.
The dimmer works as expected: Single Tap Up turns lights on while Single Tab Down turns lights off, Hold Up brightens while Hold Down dims, and the blue LED lights when the switch is off.
The Aux switch is different: Single Tap Up does nothing while Single Tap Down turns lights off, Hold Up brightens ONLY IF the light is on while Hold Down dims, and the blue LED lights when the switch is ON. 
I thought that the Aux switch was supposed to mirror the Dimmer. I've double checked the wiring, and assured that the Yellow wire is connected on both ends. My electrician also checked my work and stated that the wiring looks good, though he doesn't expect the house will pass inspection because the Aux switches won't turn the lights on by themselves. We've installed multiple pairs now, and all function the same way.
Is this how the Aux switches are intended to work or did I miss some configuration somewhere?
Thanks in advance! 
That doesn’t sound correct. It looks to me like they both behave the same here, although the blue led stays on all the time. I forget if that is configurable.

You don’t say exactly what you upgraded from in these locations? The Leviton 3-way setup requires ground and neutral at the slave location. It is common in house installs to not run an extra wire for normal 3-way circuits. Are you familiar with the difference when installing a Leviton 3-way UPB switch? (I apologize if you checked this already, but you didn’t mention it.)
Here are a couple of wiring diagrams.
Here never purchased UPB Aux switches for my three way set ups rather used regular UPB switches for my 3 ways.
Mostly used the hot / neutrals that were in all of my light switch boxes and did steal use of the traveler wires (typically not black here but yellow or blue) for hot or neutral if they were not in the light switch box.
Note that all 3-4-5 way switches always have two traveler wires.  Personally would always test and label the traveler wires with a VOM cuz sometimes they used same colors or just black wires.
Thanks guys! 
You don’t say exactly what you upgraded from in these locations? The Leviton 3-way setup requires ground and neutral at the slave location. It is common in house installs to not run an extra wire for normal 3-way circuits. Are you familiar with the difference when installing a Leviton 3-way UPB switch?
I upgraded from a Leviton HCM06 Dimmer and a Leviton MS00R-1 Aux switch. Ground and neutral wires are available at both locations, and wired into the old switches.  
The MS00R-1 had blue and yellow wires; blue was line while the yellow was control. The MS00R-1 didn't use a neutral.
When installing the 37A00-1, I followed the diagram pete_c posted above with the result of:
Black - Line
Green - Ground
Yellow - Control (pairs with yellow on the dimmer)
Blue - Neutral (lights up the Blue LED)
Gray - Capped
I double checked all of the connections and these all seem to be right. The dimmers work 100% as expected, but all of the Aux switches I installed (3 total as part of 3 3-way pairs) operate in this "broken" fashion.
Any thoughts? 
Aux UPB switches are junk. They don't feel or look like regular UPB switches, and they are very overpriced for what is actually in them. Instead just use any UPB switch with a link to control any other UPB switch.  It won't control a load, but its MUCH more flexible.  At anytime, you can change links and have you switch really control any in the house, not just the one its wired to.  More expensive, yes, a real switch is more expensive than the "remote" switch, but it the long run, you may be happier.  For me, look and feel and flexibility was worth the added cost.
It sounds like there is a wiring problem. The giveaway is your blue led behavior on the slave switch. I looked at mine this morning, and the Leviton slave led is always lit (I actually switched to SA switches for slaves because of this in other locations.)

So if your blue led is going on when you switch the master, it means your Line connection is probably a switched output (load output from the master) rather than Line (always hot) to the slave.

So if you power on the circuit, normally all leds will light, both slave and master. If you then press on at the master, the master led will go out, but slave leds will stay on. If not, the slave wiring is incorrect.
You can check the line (hot) versus load (lamp) at the master switch box with a VOM. 
Just put the leads of the VOM between the metal box (if conduit is used) or the neutral lead (white typically) and check for 120VAC on the two leads in the master switch box.
Note if you are not comfortable doing this then I would call an electrician.
1- shut off the breaker for the circuit in question
2 - pull all of the wires out of the switch box
3 - separate them well and remove the caps: if the leads untwist and come apart use a pair of pliers to twist them back together.
4 - turn on the breaker for the circuit in question
5 - do not touch the wires while testing the leads with the VOM.
I have seen here sometimes both line and load are black wires but most of the time they are blue or yellow wires here and neutrals are all white here.  For 3-way wiring my travelers were orange (two orange wires).  Double checked all of the wiring with a VOM and labeled it any how.  Low on the WAF as I pulled a few wires out of a few switches and left them that way for a couple of days of testing.
Thanks, folks! It was a wiring problem (load was connected instead of master). It also explains why some of the old X10 Aux switches don't work. I swapped the wires and now everything works correctly.
Great! I figured that was the problem when I saw my aux switches have their blue LED always on.
I noticed there was alot of discussion last month on the 3-way Aux switch issue.  I would like to add my 2 cents worth.
I agree with Ano.  I never use the Aux or Remote switch.  I always use another 600W dimmer at the "remote" location with link control.  I call it a "pseudo 3-way".  The main advantage is that you can sync the LED control, same color at both switches.  And the feel of the switch in the same.
Good point about changing the link.  You could control a different switch or device down the road.