No power at the 7 pin connector

[budwilson]

I am trying to wire the car for towing. I have all lights rt, lt, brake, and tail lights on the back of the 2006 Discovery Freightliner chassis. I only have right turn and stop light power on the 7 pin Connector on the back of the mh, no other pins have power. Is there a separate fuse panel for this connector? If so can you tell me where it is. Thanks

[Gary RVRoamer]

You may have bad wiring to the trailer connector. Typically the wiring to the trailer connector comes off the chassis brake & signal fuses that are usually located in a rear bay on the passenger side.

[budwilson]

Do you know which bay it is in and what to look for?

[Bigd9]

Good evening Bud,
On my 2006 35H Discovery there are two relay boxes located inside the passenger side lower compartment right behind the rear axle (the one where the spare tire is supposed to be stored). One of them is for the trailer plug. Also I believe inside and up front behind the dashboard swing out cup holder cabinet there are fuses for the trailer plug.

To find the relays, just turn on the right turn signal and go back to that compartment and let the clicking of the relay lead you to the correct box.

If this was me, once I found the correct box I would then try the left turn signal (the one you say the plug does not have power) and see if the relay clicks. If the relay is clicking then the trouble is between the relay and the plug. If this is the case, my bet is on the actual plug itself being corroded thus causing the wiring to make a poor connection.

I'll see if I can find a picture or two. Or tomorrow I can take a few if this is what you want. Just let me know, OK

[budwilson]

Originally Posted by Bigd9

Good evening Bud,
On my 2006 35H Discovery there are two relay boxes located inside the passenger side lower compartment right behind the rear axle (the one where the spare tire is supposed to be stored). One of them is for the trailer plug. Also I believe inside and up front behind the dashboard swing out cup holder cabinet there are fuses for the trailer plug.

To find the relays, just turn on the right turn signal and go back to that compartment and let the clicking of the relay lead you to the correct box.

If this was me, once I found the correct box I would then try the left turn signal (the one you say the plug does not have power) and see if the relay clicks. If the relay is clicking then the trouble is between the relay and the plug. If this is the case, my bet is on the actual plug itself being corroded thus causing the wiring to make a poor connection.

I'll see if I can find a picture or two. Or tomorrow I can take a few if this is what you want. Just let me know, OK

Thanks any help you can give is really appreciated. I'm not sure what the problem is but I think it's a fuse someplace.

[Bigd9]

Here is a picture I just found. The relays are in one of those two small black boxes.

[Bigd9]

If you can hear the relays clicking, then the fuses are probably good. If I don't forget, tomorrow I can get a picture of the fuse box location.

[budwilson]

Thanks again. I'll look tomorrow and see what I can find

[budwilson]

Originally Posted by Bigd9

If you can hear the relays clicking, then the fuses are probably good. If I don't forget, tomorrow I can get a picture of the fuse box location.

Pete, Did you find the picture of the fuse box yet? I found the two relay boxes and another box between them but don't see any way to get into that box.
Thanks again
Bud

[budwilson]

Thanks everyone I found the blown fuse in the relay box and it's just about back to normal. The right signal and tail light is very dim so I'm going to replace the bulb before I try anything else. Any other suggestions on the dim bulbs?

[Bigd9]

Originally Posted by budwilson

Any other suggestions on the dim bulbs?

When I call my wife this I end up in the dog house!!

Dim bulbs usually mean low voltage or poor grounds. Check the voltage at each socket and see if you are getting close to 12+ volts on the tail and stop lights. If you check the turn signal bulbs keep in mind they may not show a true voltage reading since a lot of mulit-meters are slow and the voltage keeps going on and off, on and off.

Also check and recheck grounds. My Daddy always said when he had problems with voltages he always looked for a bad ground first thing. He worked for RCA on this nations first satellites and parts for the space rockets in the early years.

If it was me, if I saw poor voltages back at the toad lights, the first thing I would do is to run a temporary ground wire from the bulb socket to the negative on the RV battery. That should rule out and bad/poor connections at the plug or any of an assortment of grounding lugs scattered around.

I just re-read your post. Is the Left tail light bright and the right tail light dim? If so then once again I would look for clean bulb connections and clean grounds. Maybe the bulb socket os a little corroded.

I just took a bunch of pictures of the relay boxes and the fuse panel up front. Do you still need any?

[budwilson]

Yes the left tail and signal is bright as it should be. The right side is dim so I'm not sure it would be the ground, but anything is possible when I'm working on anything. If you want I can always use pictures to help me find things. Thanks for all your trouble.

[Bigd9]

Since both the tail and signal lights are dim, and they are completely
separate circuits from each other, I still vote of a grounding problem, or
corrosion at the light bulb socket. BTW Bud, we are talking about the toad
lights, righ? The Discovery lights all work as advertised, but the toad is
the one giving you fits, right?

I'm not sure what pictures you need especially since you found the blown
fuse. BTW, was the fuse in the relay box in that last compartment behind
the rear axle bad or was it the one up front behind the cup holder cabinet
the one that was bad?

I just finished the grease/oil/filter/fuel filters/antifreeze change out.
Either this work is getting mechanically harder to do, or I'm getting to
old.....probably the work is getting harder, right?

Take care,
Pete

[budwilson]

Yes we are talking about the toad, the Discovery. The signal light and tail light work when not connected to the Discovery so it must not be the bulb or the socket. It's getting a good ground to the left side since they work so I guess I'll try something tomorrow.