Help! Tail light news flash!

Falcon190 · 11-21-2013, 02:44 PM

I think this may be the first time you've read about an electrical problem that's NOT caused by a loose ground wire! My tail lights won't light. The brake light is in the same bulb (and socket) and works. The bulbs are good. The fuse is good, though I've read that there is rear fuse box by the radiator. If there is I couldn't find it. All other outside lights are working. There's just no power to the tail lights.

My question is: Can I tap into the rear marker lights or is that a problem?

2003 Winnebago Ultimate Freedom 40KD

skigramp · 11-21-2013, 03:12 PM

I don't know if this is true for "Ultimates" ... but it is true for my Journey ...

Turn on your flashers ... and walk around your coach until you locate it ... mine is in the backmost compartment on the street side hidden behind a metal panel ... and right beside the flasher are the fuses for the trailer connections, the rear markers, ...

I think this thread may be useful to you ...

Fuses

Give it a shot ...

Shadowcatche · 11-21-2013, 03:47 PM

Do you have a positive indication, or negative, that you have no power to the socket? Do you have access to the back of the housing? I would be going after the fault and if all else fails using a wiring tracer. There is a fuse some place, probably in the main automotive/chassis fuse block!

NeilV · 11-21-2013, 04:30 PM

Are you certain that its the brake light filament that is lighting?

When you have a bad ground the running light filament will sometimes light when you step on the brakes.

wa8yxm · 11-21-2013, 04:50 PM

I agree with the bad ground issue.

Try this. Using a TEST LIGHT, not a volt meter but a TEST LIGHT (I will instruct)

Ground one lead of the test light to a known good ground, The hitch receiver may work, Verify that it is grounded by other means (For example touch a marker light lead or use the towing connector, on a flat 4 the odd pin is ground, the one next to it is tail lights.. This came in handy for me once.

in fact that "odd pin" might be a good choice of ground.

Now, test the tail light lead or contact in the lamp socket (if you have 1157 type lamps test both "Center" contacts) NOTE, do so carefully, i'd insulate all but the very tip of the test lamp probe)

If the light works, you have a ground problem.

Move the clip to the 1st insluated contact on the flat 4 connector, test by touching the point to a known good ground (The odd pin?) it should light if the clip made contact.

now touch the tip to the shell

If you have WEDGE shaped base lamps.. It is a bit harder to figure out which of 4 wires is which.

KIX · 11-21-2013, 05:07 PM

Have you looked at the wiring diagram for your moho at Winnebagoind.com When you find the diagram you will get an idea of where the fuses are located.

Excuse me.........what you would be looking for would be on the chassis mfr. schematics. I think your coach is on a Spartan.

Falcon190 · 11-21-2013, 06:20 PM

Thanks all for responding. After looking at the picture, my Ultimate is set up completely different. The water and electrical are in two separate compartments and it seems all fuses are in the front on the street side. I used a VOM to test the wiring after looking for loose connections, of which I found none. The brake and tail lights are in one bulb and the brake light works so there has to be a ground. And the pin on the trailer socket for the tail light also works, as well as the lights in the toad. Everything works except the two tail lights. Argh!!!

skigramp · 11-22-2013, 07:39 AM

I had a similar problem on my 2004 Journey a couple of years ago ... all my marker lights worked except the ones up high on the rear of the coach.

The problem was a corroded connector from where the chassis manufacturer (Freightliner in my case) and Winnebago made the connection. The fix was to replace the connector. The connector was located at the very rear of the frame rail on the curb side. I suggest you call Winnebago Customer Service to see if you have a similar connector that might be the problem.

There was no blown fuse ... just a corrupted connection inside the connector.

jerichorick · 11-22-2013, 12:46 PM

Here are a couple of diagrams. I think skigramp might have the right idea.
http://www.winnebagoind.com/diagram/...ire_131521.pdf
http://www.winnebagoind.com/diagram/...ire_141426.pdf

Hope these help.

If you see a bulge in the harness tape leading away from the light chances are it is a connector. These are hard to locate. If you had a signal tracer it would be a helpful but not always. Sometimes the signal radiates into everything and is hard to isolate.

Hope to hear a success story soon.

Rick

Falcon190 · 03-21-2014, 11:24 PM

It's been awhile but I solved the mystery today. In the front driver's side basement compartment there are all the fusses. The taillight fuse was ok.

But today I noticed a black box next to it about an inch square. I pulled it and exchanged it for another and yep. The lights worked. It's a small relay. One of about ten identical relays. I went to an auto parts shop and for about $18 I'm back in business. What did I do in the mean time? The few times we were out I drove during the day!

Ray,IN · 03-22-2014, 10:11 PM

W made a change between 2000 and 2003. All the 12V fuses and relays for the chassis are above the genset on my 2000 UF.

Dave78Chief · 03-23-2014, 07:13 AM

Depending on manufacture, the trailer fuse box tends to get placed in all sorts of places

As you discovered it contains both fuses and isolation relays.

These are used a lot on Diesel chassis'. It is complete separate from normal under dash fuses. Original intent was to isolate the main system (tractor or motorhome) from the trailer system. Motorhome Mfg's tend to tap off it for the rear lighting system also.

As Skigramp indicated in Post #2 above (http://www.irv2.com/forums/f101/help...ml#post1815866), you need to turn flasher on and go locate the hidden box. Might be best to go find it now so you can check it easier later when a problem arises.

Dave

Falcon190 · 03-25-2014, 10:30 AM

Quote:

Originally Posted by Dave78Chief

Depending on manufacture, the trailer fuse box tends to get placed in all sorts of places

As you discovered it contains both fuses and isolation relays.

These are used a lot on Diesel chassis'. It is complete separate from normal under dash fuses. Original intent was to isolate the main system (tractor or motorhome) from the trailer system. Motorhome Mfg's tend to tap off it for the rear lighting system also.

As Skigramp indicated in Post #2 above (http://www.irv2.com/forums/f101/help...ml#post1815866), you need to turn flasher on and go locate the hidden box. Might be best to go find it now so you can check it easier later when a problem arises.

Dave

Thanks again everybody for your help. As far as checking for a remote fuse box, I've already done that and everything having to do with flashers, fusses, and relays is in one compartment in front. And more importantly, the problem has been solved!

As a side note, though my stop light and tail light are on separate circuits, they share one bulb with two elements. I found that it does make a difference how the bulb is plugged in as one element is considerably brighter than the other so if you have the same setup and your taillights are dim you might try turning the bulb around.

Ray,IN · 03-25-2014, 02:45 PM

Quote:

Originally Posted by Falcon190

Thanks again everybody for your help. As far as checking for a remote fuse box, I've already done that and everything having to do with flashers, fusses, and relays is in one compartment in front. And more importantly, the problem has been solved!

As a side note, though my stop light and tail light are on separate circuits, they share one bulb with two elements. I found that it does make a difference how the bulb is plugged in as one element is considerably brighter than the other so if you have the same setup and your taillights are dim you might try turning the bulb around.

The 1157 tail/running light, stop light combination bulb may not be simply 'turned around', as the retaining pins on the base(and in the socket) are at different heights. This locates the bulb so the brighter filament is always positioned onto the brake circuit wire.

garykk · 03-25-2014, 04:03 PM

Quote:

Originally Posted by Ray,IN

The 1157 tail/running light, stop light combination bulb may not be simply 'turned around', as the retaining pins on the base(and in the socket) are at different heights. This locates the bulb so the brighter filament is always positioned onto the brake circuit wire.

Makes me wonder if the right bulb was in there.....