Fuses for interior lights keep blowing

[menoco]

When my 2002 Hawk was hooked up to shore power, the interior lights would not come on. Had worked week before. Went to change fuses, and 3 in a row blew out. I could hear and sometimes see the fuse go. A spark as fuse going in. Unplugged from shore power, and still blew out 2 more fuses. That used up entire box. The only change I can think of is that 3 days ago, I installed a new battery in truck, not the camper.
Unfortunately I'm hitting the road for the desert today - winter has come to Wyoming - so any repair must be done on the road. But then, I'm well set up to camp w/o interior lights.
Frankly don't even know what other facts might be relevant to solve problem. Hope it isn't anything as substantial as post from FWC. http://www.wanderthewest.com/forum/topic/8948-tech-tip-service-bulletin-camper-to-roof-wiring/?hl=%2Bfuses+%2Blights
Only thing I would add is that although we love our FWC camper, the electrical system has been problematic. Can't thing of a single trip where something in electrical system didn't go wrong.
Any help welcome
Armando

 

[highz]

Unfortunately, the wires shorting behind the lift panel are a likely cause...

It isn't that hard to repair them, though.

 

[NorCalSteve]

I would start by removing the bulbs and hope the fuses stop blowing. If it does, you probably found your problem. Not sure if you would have LED bulbs or not. After that, it is visual inspection time. I think the roof issue is usually a broken wire and not a short. But there could still be issues in that area.

Cross your fingers.

Steve

 

[camper101]

FYI if it is the wiring behind the panels I would grab a packet of butt splices (yellow for #12 wiring in my case) just in case you find yourself with some time to kill.

It is a bummer to have to make the repair, but it's not too difficult. There was plenty of extra wire behind my panels, and you might not NEED to add extra wire if you just want to get through this trip with lights.

[On preview: I see that highz says roughly the same thing...]

You could do a more permanent fix when you get home. I ended up leaving the wires off to the side (not taped behind the lift panel).

In fact, I'd almost hope that's the problem -- anything else could be more trouble.

 

[esimmers]

Sounds like the problem's either 1) a shorted wire between the fuse and the lights (most likely) or 2) one of the light fixtures or bulbs is defective (unlikely). Turn off the on-fixture light switches (best) or remove the bulbs (assuming they're incandescent, if they're fluorescent then make sure you turn off the fixture switch since just removing fluorescent bulbs still leaves the ballast in the circuit).

If the fuse still blows, then, like another person said, there's a short somewhere where the + wire, (black is ground) is contacting a ground wire or the aluminum frame that is itself connected to the ground somewhere. As stated before, it's probably behind the front lift panel where the wires flex every time you raise or lower the roof.

 

[menoco]

Sorry I had not responded to thank folks for the advice. As I had said, I was on the road, unable (unwilling) to attempt repairs. Survived fine with battery-powered lights.

Now that home, I started with the easiest suggestion: take out bulbs and re-insert a fuse. Fuse didn’t blow. Put bulbs back in, and now the lights work! Both DC and AC power.

Don’t think I fixed anything. In fact, does this make a short more likely? I’ve raised and lowered roof, driven on 4W roads, and maybe a shorting wire has shifted? I had not tried lights with fuse in until after removed/replaced bulbs. Could well have worked before I tried to insert fuse w/o bulbs.

Of course, something else now doesn’t work: a familiar problem for my Hawk. A furnace fan that will not turn off. In past, I had to pull the furnace fuse. Turning to lowest setting, and shutting gas wouldn’t stop fan. But this spring, I got a new thermostat from FWC with an ON/OFF setting, and it has worked until today as I was testing the lights. Now, with thermostat in OFF position and gas off, as soon as I plugged in on-shore power, furnace fan came on and stays on. (perhaps fan had run until camper battery too low, and that’s why it came on when plugged in AC?) Now fan will run on DC or AC when I insert furnace fuse.

Could these be related problems? Some mistake installing thermostat is the source of lights shorting out?

Armando

 

[camelracer]

I don't think the problems are related. I would suspect that the lighting problem is caused by the wires behind the lift panel shorting. These wires move slightly each time the roof is raised or lowered so the short can come and go. Pull the wires out and check them out. It's a poor design using the wrong type of wire.

I don't have a heater schematic but I would guess that there's a fan control relay on the control circuit board that's hanging up. The thermostat doesn't directly control the fan.

 

[menoco]

Thanks, Camelracer. That's good information. I couldn't think of any way the lights and furnace fan problems are related.

 

[Beach]

Earlier post about wiring: http://www.wanderthewest.com/forum/topic/8948-tech-tip-service-bulletin-camper-to-roof-wiring/?hl=%2Bwiring+%2Bbehind+%2Blift+%2Bpanel
Next time the fuses keep blowing you can ck to see if the wiring is shorting to the camper frame. Remove the bulb and use a ohm meter to ck for continuity between each socket contact( + and -). Connect one lead to a socket contact and connect the other lead to the aluminum frame. You should NOT have continuity. If you do have continuity, you have a short. If all is good, move the lead to the other socket contact and ck it. Fuse does not need to be installed for this test. If this situation is intermittent then you might have a difficult time tracking it down.

 

[billharr]

Saw this on another site. Have not tried but might is I can't find a short some day.

Originally Posted by Viking Panels
One way to find a short, is by buying an auto-reset circuit breaker in the same amperage as the fuse that's blowing. If you can find one that fits in your fuse box, in place of the fuse, that's even better.

If it won't fit in the fuse panel, attach two leads to the breaker, and attach to the contacts in place of the blowing fuse. Have someone activate the circuit continuously if a momentary switch needs held/applied.

Get a quality compass, and start following the wire as the breaker trips and auto-resets. The needle will move each time there is power applied to the circuit. (creating a new magnetic field)

When the needle starts to move less and less with each cycle, you are within a few inches of the problem.

Hope this helps.