I recently purchased a 1996 16x80 Belmont Mobile Home. The master bathroom has one GFCI outlet, lights over the sink, an overhead light, and a vent fan. Nothing was working in this bathroom when I purchased the home. The GFCI would not reset so I assumed it was faulty. Today I removed the GFCI and tested the bare wires: 2 sets of wires each with black, white, and ground wires. The GFCI is 15A and the breaker to this bathroom is 15A. With the switches for the sink lights, overhead light, and vent fan off (at least flipped in the down position) one set of bare black and white wires tested 85 volts and the other set was zero. When the sink lights are turned on (switch flipped up - remember they are not burning - nothing in the bathroom works) the original GFCI wires tested at 85 volts are now zero volts and the original set of wires which were zero now test 75 volts. My tester identifies outlets in other areas of the home which are working as 125 volts. It also test 125 volts at the 15A breaker when it is on and zero at the breaker when it is off. When the sink lights are turned off (switch flipped down) and the switch for the overhead light is flipped up (remember the overhead light does not burn) the same thing happens as what happened when the switch for the sink lights were flipped up. Any idea what could be causing this anomaly?

Sounds like a loose neutral wire. Are those switches actually marked with a small ON and OFF or are they blank

They are blank. So, there could be a loose neutral wire at the lights, fan, or switches causing the loss of voltage?

Blank switches are almost always a three way switches. Up does not mean ON and down does not mean OFF so be careful. The loose nuetral could be at the switch itself especially if they are back stabbed. You have to hunter th ecircuit with your tester starting from a point where you still get 120 vac

The only place I get 120 volts is at the breaker itself. Nothing in the master bathroom tests more than 85 volts. Any idea how mobile homes are normally wired? Are the bathroom lights and bathroom vent fans normally run through the GFCI?

So the wire coming to the box only shows 85 volts between the white and the black? Check all of the screws on the white wires in the box itself, put a driver on every screw and try to tighten it, shut off you main just to be safe when working inside the panel

I have completely removed the GFCI and only the bare wires are exposed. 85 volts register between the black and white wire on one set and zero on the other set. Then, when I flip the switch, that set shows zero and the other set now shows 75 volts. This would make me think the lights and vent fan are also somehow running through this GFCI outlet.

Sometimes its hard tp pcirture what folks are saying but I think you have a set of wires coming into the box from the panel, they are giving 85 volts. The other set is most likely the wires leaving to box heading to the light. Have you tightened the screws on all of the white wires in the panel yet?

Is it normal for the bathroom lights and vent fan to be connected to a GFCI in a mobile home?

Yes, in any bathroom

I am not actually at the mobile home now. I will try that tomorrow.

OK Ill be around tomorrow as will several others who know wiring.

Correct me if I am wrong but wouldn't the wire have to be running from the breaker to one of the switches, lights, or fan first and then to the GFCI in order for the wires to switch voltage since they are not physically connected to anything at the GFCI outlet box?

We are talking about a GFCI outlet receptacle right? http://www.westsidewholesale.com/leviton-7599-w.html?mr:trackingCode=DDD60BFC-0E09-E311-B773-BC305BF933C0&mr:referralID=NA&mr:device=c&mr:adType=pla&mr:ad=26456887525&mr:keyword=&mr:match=&mr:filter=35578079116&mkwid=WlktAIIH&pcrid=26456887525&pdv=c&gclid=COrexe3j_roCFSVgMgodJ00A-g

Yes, but like I said at the beginning, I removed the GFCI outlet thinking it was bad. After totally removing it (only wires poking out of the outlet box now) I tested the wires for voltage and learned of the low voltage.

First lets keep in mind that you never know who has done what to that home since 1996. Many diy projects go a liitle beyond code. Two wires, one white and one black, have to bring power from the panel to the GFCI, those are the ones you are getting 85 vac from. Very frequently two there wires, white and black, are attached to the other side of the gfci to provide power eslsewhere in the room and provide gfci protection.

Thanks for your help. I'll take a look at the connections at the switches and then lights and fan. I'll let you know the outcome tomorrow.

Thanks ballengerb1 for all of your help. Sorry I took so long to let you know the outcome. You indeed steered me in the correct direction. The problem turned out to be a neutral wire that had been cut. The previous homeowner had replaced a section of an exterior wall and had cut through a neutral wire. You saved me hours upon hours of not knowing how to correctly search for the problem. I am very appreciative of your help.

You are welcome and thank you for the tip.