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snkrichards · 11-19-2010, 01:00 PM

My service manual hasnt arrived yet so in the mean time I'm trying to figure out how it is that a 12v light fixture can show 13v but the light still doesnt work. All the lights work except the reading light by the bed and the bathroom lights. This thing blows up light bulbs like popcorn. does anyone know the wiring configuration. Thank you

wkerfoot · 11-19-2010, 01:20 PM

I hope someone has the answer, I have the same problem with the light over the door on my 1979 Safari.

Bill

Quote:

Originally Posted by snkrichards

My service manual hasnt arrived yet so in the mean time I'm trying to figure out how it is that a 12v light fixture can show 13v but the light still doesnt work. All the lights work except the reading light by the bed and the bathroom lights. This thing blows up light bulbs like popcorn. does anyone know the wiring configuration. Thank you

Inland RV Center, In · 11-19-2010, 02:15 PM

Quote:

Originally Posted by wkerfoot

I hope someone has the answer, I have the same problem with the light over the door on my 1979 Safari.

Bill

There can be 2 different answers, depending on if the light socket has 1 or 2 wires going to it.

Andy

snkrichards · 11-19-2010, 03:32 PM

the ceiling light and reading light have two wires. The light over the sink has three. Right now the only one showing any voltage is the light at the sink. It might be a flaky switch. Anyway your advice would be very valuable. thanks

wkerfoot · 11-19-2010, 03:39 PM

Andy,

I don't remember how many wires. What are the two answers?

Bill

Quote:

Originally Posted by Inland RV Center, In

There can be 2 different answers, depending on if the light socket has 1 or 2 wires going to it.

Andy

Inland RV Center, In · 11-19-2010, 03:45 PM

Quote:

Originally Posted by snkrichards

the ceiling light and reading light have two wires. The light over the sink has three. Right now the only one showing any voltage is the light at the sink. It might be a flaky switch. Anyway your advice would be very valuable. thanks

The light over the sink is controlled by 2 each 3 way switches. One is on the light and the other is by the entrance door.

Andy

Inland RV Center, In · 11-19-2010, 03:49 PM

Quote:

Originally Posted by wkerfoot

Andy,

I don't remember how many wires. What are the two answers?

Bill

Either 12 volts is fed to the lamp thru a switch, or 12 volts is always on the lamp, but the return circuit goes thru a switch to ground (two terminals).

The 1978 service manuals do not have a model specific wiring diagram. The only diagram is general in nature.

Andy

snkrichards · 11-19-2010, 04:07 PM

I just went out side and the light sink light magically came on? the other two are dead. no volts no nothin.

wasagachris · 11-19-2010, 04:13 PM

snkrichards both lights are on different circuits and the galley light is on a third circuit. If all fuses are good and all other lights work. Then either you have a broken wire to each light or as you say the sockets have two wires then you have no ground. If you keep poping bulbs I would suspect the sockets. Are you sure you have the right bulbs in them. The bulbs should be #1141 and only have one contact point at the bottom of the bulb.

snkrichards · 11-19-2010, 04:16 PM

thanks I'll check this out before I ask any more questions.

snkrichards · 11-19-2010, 05:35 PM

I have discovered several fuses with hots to the top and nothing coming out the bottom. seems odd. It looks like some of the other circuits have been wired into the main 50 amp hot. wiring mysteries are so much fun.

wasagachris · 11-19-2010, 05:41 PM

Snkrichards well if the fuses are "hot" on top and nothing on the bottom it's obvious that the fuses are blown. You should correct the other circuits that are wired into the 50 AMP hot because if you get a short to ground on those circuits the wires are too small to carry that much amperage and will melt and start a fire! You also have the potential of pulling that much amperage through an improper load(light, fan etc) and have the same result(FIRE).

snkrichards · 11-19-2010, 05:58 PM

I meant there was a hot wire to the top of three fuses; the fuses are good but no wire coming off the bottom of those three fuses.

snkrichards · 11-20-2010, 03:01 PM

Well I've isolated the circuits. The only thing not working now are the light on the bathroom ceiling and the reading lamp. If I can figure out where they originate I'll be set. Thanks

wasagachris · 11-20-2010, 07:45 PM

I'm looking at a 73 service manual so it may be different for your 78.
Circuit #1 the purple wire feeds the bathroom light. The 12VDC outlet in the bathroom is first in that circuit so check it for power. If it's dead then you have a broken wire feeding those two points. Next in that circuit is the overhead light in the bedroom and it ends there.
Circuit #2 the yellow wire feeds the bed shelf light and the 12VDC outlet there as well as the fan in the overhead bedroom light. Again check the outlet there. the last item in that circuit is the fan in the overhead light in the galley(kitchen).
Since your'e not blowing fuses then you do not have a dead short. I know it sounds stupid but did you check the bulbs in a working light to make sure the bulbs are not the problem. If the bulbs work then check the sockets with a multimeter. Positive probe to the wire and negative probe to the shell for a ground. If you have no power then a broken 12VDC+ is the problem. If you have power then the lamps are not getting a ground.

snkrichards · 11-21-2010, 05:24 PM

I hadnt seen your post until now thanks. I found that the yellow wire you're talking about had some corrosion so I took it off and squirted some wd 40 on the terminal then reconnected it. The light over the bed and the one in the bathroom overhead are on now. funny thing is the one over the sink suddenly quit working. Has 12v but won't light a bulb. The 12v outlet shows no voltage. I suspect I'll need to clean up additional fuses.

snkrichards · 11-23-2010, 08:45 PM

Ok I got them all fixed thankyou. It turns out that in front of the inverter and behind the fuse box is an opening to the outside. it must be some kind of access port of some sort. It appears that it once had been sealed. The sealing had worn out allowing water to get on the fuse box and rust it up worse than I thought. Anyway I cleaned it up and now all the lights work. On to the bathroom fan.