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HR2004 · 03-13-2018, 10:25 AM

2008 pheaton. Qth
What is this plug and receptical for. It is not the block heater. The heater is a labled cord and plug. Inside the junction box this plug comes from is a relay. ????
There is no power in the receptical. Is there a switch for it?
Thanks for your help

**Lt Dan** · 03-13-2018, 11:28 AM

Try turning on the block heater switch on the dash then see if the outlet has power. The block heater outlet is normally controlled by a 12v relay and switch. I know you said it's not the block heater, but give it a try as that is usually a relay controlled outlet.

HR2004 · 03-13-2018, 01:38 PM

Thanks. Will check that out after lunch. I'll post what we find out

HR2004 · 03-14-2018, 09:15 AM

Nope. Not the block heater. It is another outlet and working fine off the dash switch. The relay in the picture is in a clear box and the contacts do not move when heater is activated. So it is working off another relay. Guess he will find out what this other plug and dead receptical are for when he goes to Red Bay. . It is not shown on the factory provided schematics.

burfurd · 03-15-2018, 07:28 AM

Suspect anything! The block heater plug and relay was NOT even installed on our Phaeton. The block heater was plugged into another 110 receptacle and was on all the time. The wife kept noticing the floor was warm over the engine. Got to checking and found the problem. Tiffin rep at Lazy Days had to install by running wiring from across to other side of motor home where switch control terminated.

Do not think any two are built the same!

I would suspect that the plug and relay were installed with no wires ran across the frame to wire up the relay to the switch. Your block heater switch may be working including lighted indicator but not be switching the relay due to missing wire.

Are you absolutely certain your block heater is on when you switch it on?

burfurd

ernieh · 03-15-2018, 03:43 PM

Can't say for sure on your 2008, but on my 2012, there is a "always hot" outlet in the electrical bay. A short cord from the relay box plugs into the "always hot" outlet and the block heater cord plugs into the relay controlled outlet.

There is a virtually identical setup that provides 120v to the water heater. On my coach, the water heater relay is in the box with the heater, but I believe that some TMH coaches had the water heater relay in the electrical bay.