I have a 8965 WFCO converter and a Onan 3600 generator for my horse trailer living quarters. Here are my symptoms. When running the gen all the 110 side works but not the 12V side. The 12v only is working off the battery. When I cut the gen off and plug in to shore power nothing works. When plugged in to shore power I get 110 to all my breakers in the converter but none of the 110 plugs, the ac or microwave work. When I call wfco they tell me the 110 shore power does not go through the transfer switch and don't understand why nothing is working on the 110 side if I am getting 110 at the breakers. I also discovered that with my GFCI in the bathroom (which is next to the converter) that when the gen is running the gfci works as well as everything 110 and I have 110 on the black wires and nothing on the whites (when metering the white and ground BUT when I am plugged into shorepower I get 110 on all four wires. Blacks and ground 110, whites and ground 110 and the gfci does not work. Banging my head on this one so any help is greatly appreciated.

Are you plugged in at home? Is it a regular 110v outlet or is there a chance you plugged into a dryer outlet?

Is this a NEW problem?Has 110V AC worked on shore power and from gen in past?Has 12V DC worked when on AC power and when not on AC power before?Horse trailer...is this a 'commercial install' or a 'home install'?AC shore power comes into one side of 'transfer switch'Gen AC power comes into one side of 'transfer switch'AC power to rigs AC Panel comes out other side of 'transfer switch'(Transfer switch flips from one input source to other)AC Panel (with circuit breakers)Power comes from transfer switch to MAIN CB (30A or Double 50A0Hot Bus feeds individual CBs to A/C, Microwave, outlets, 'converter'Converter takes 110V AC power input and converts to 12V DC outputBattery cables connect to converter busBus feeds individual fuses to lights, water pump, furnace, fridge/water heater controls etc.Converter supplies DC system when on AC power sourceBattery feeds DC system when not on AC powerSo if gen feeds AC Panel----then converter should be feeding DC System unless converter has failed OR AC input CB has trippedWhen swapped over to shore power.....either you have AC power from transfer switch or you don't.Can't have AC power at AC Panel and not thru individual CBs unless MAIN CB has tripped (or individual CBs are tripped)DC System is feed from converter or from battery...unless battery is dead, disconnect switch is OFF or 'reverse polarity' fuses on converter have blownStart with just battery....no AC and check that DC System worksThen check with one AC source and check voltages on both AC/DC SystemThen swap to other AC source and repeat checks.One system at a time....

Thanks Old Biscuit, more detailsFactory installed living quarters. This is a new problem, everything has worked fine for 4 years until now. It is a 110 system. We took the trailer out in July and noticed the lights would dim and go bright several times an hour. e thought maybe it was because it was a full campground on the 4th of July weekend. Then the next time we used the trailer which was this week we were plugged into just a 110 for lights and tv and bam, tv goes off and micro clock goes out and we were back on dc battery power.

Why is the 110 side working on gen and not the shore side and why is the gen power going to 110 but not sending power to 12v stuff

Randemgun wrote:when I am plugged into shorepower I get 110 on all four wires. Blacks and ground 110, whites and ground 110 and the gfci does not work.This sounds like 220 or bad polarity.Ground to neutral should be very close to zero volts in all conditions.Is this a 30 amp or 50 amp RV?

WFCO 8965 converter | Good Sam Community

12 Replies

Old-Biscuit
Explorer III
Oct 12, 2014
Is this a NEW problem?
Has 110V AC worked on shore power and from gen in past?
Has 12V DC worked when on AC power and when not on AC power before?

Horse trailer...is this a 'commercial install' or a 'home install'?

AC shore power comes into one side of 'transfer switch'
Gen AC power comes into one side of 'transfer switch'
AC power to rigs AC Panel comes out other side of 'transfer switch'
(Transfer switch flips from one input source to other)

AC Panel (with circuit breakers)
Power comes from transfer switch to MAIN CB (30A or Double 50A0
Hot Bus feeds individual CBs to A/C, Microwave, outlets, 'converter'

Converter takes 110V AC power input and converts to 12V DC output
Battery cables connect to converter bus
Bus feeds individual fuses to lights, water pump, furnace, fridge/water heater controls etc.
Converter supplies DC system when on AC power source
Battery feeds DC system when not on AC power

So if gen feeds AC Panel----then converter should be feeding DC System unless converter has failed OR AC input CB has tripped

When swapped over to shore power.....either you have AC power from transfer switch or you don't.
Can't have AC power at AC Panel and not thru individual CBs unless MAIN CB has tripped (or individual CBs are tripped)

DC System is feed from converter or from battery...unless battery is dead, disconnect switch is OFF or 'reverse polarity' fuses on converter have blown

Start with just battery....no AC and check that DC System works
Then check with one AC source and check voltages on both AC/DC System
Then swap to other AC source and repeat checks.

One system at a time....
time2roll
Nomad
Oct 12, 2014
Are you plugged in at home? Is it a regular 110v outlet or is there a chance you plugged into a dryer outlet?

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WFCO 8965 converter

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