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Janet&Sid · 10-14-2010, 03:14 PM

I need help. When I connected my Saturn to my motorcoach the turn signals work fine and the tail lights work fine, but when the brakes are applied the tow vehicle and motorcoach brake lights flash 1 second on 3 or 4 seconds off. If the connection is removed from the Saturn the motorcoach's brakes act normaly.
So far I have found a broken ground connection in the Saturns wiring harness and corrected that problem.
The coach's previous owner installed an electric brake controller and a 7 pin plug in the rear, The Saturn (2000) has a flat four pin connector.
I made a four wire coiled wire connector with a 7 pin on one end and a 4 pin flat on the other end.
It seems like I have a back feed somewhere but I am at a total loss as to where. I have a change to the coach wiring from manufacures wiring diagram and a Roadmaster wiring harness that appears to be wired correctly and my cord adapting one to the other.
HELP. Better half assumes the problem is in my cord. But I don't think so.
Sid

Jim A · 10-14-2010, 06:45 PM

An Alpine Coach has separate amber turn signals and red brake lights. If your toad has the same setup, amber turn signals and red brake lights, a four pin plug is not sufficient to be wired correctly. There is an adapter with diodes required to make the amber turn light/red brake light systems work with red turn/brake light systems. I don't have that problem, so I am not an expert in it.

If you simply wired wires together in your 7 pin to 4 pin cable, you need to fix that.

Jim A · 10-14-2010, 07:19 PM

Here is an article on toad wiring. It discusses a 5 wire system like on the coach to a 4 wire system, which might be what is on your toad. (That is how it is apparently wired. But check to see if it should have been wired as a 5 wire system. I would have thought Saturn's would be a 5 wire system.)

RV Tech Library - Tow Vehicle Wiring

Janet&Sid · 10-14-2010, 08:18 PM

Thanks Jim.
The seperate brake and tail light set off a lightbulb of it's own for me. Looks like I will be needing a diode to stop the backfeed and a seperate wire for stop lights. We bought the Saturn because it was tow ready, I am chuckling to myself over that.
Thanks again for setting me off in the right direction.
Sid

johnwr · 10-15-2010, 12:04 AM

Since our toad needed to be wired from scratch to tow, I installed a dedicated bulb in the lens cavity for the tail/turn/stop lights. I know this isn't your approach, but I experienced a common problem among Alpine owners, that the tail light converter failed, and/or the stop/turn lights stopped working due to the extra current draw through the Vanesco system. If you desire, look at my post on this to see how I solved the problem. I hope your solution is as simple as adding another wire and diode(s).

EngineerMike · 10-17-2010, 11:02 PM

Sid- the flashing is some sort of signal of Vansco "trouble", perhaps an overcurrent triping the particular circuit's overcurrent protection which then resets. Here is how to read the LED's on the rear Vansco which powers the plug pins:
If an output LED is FLASHING, the corresponding output that the LED
represents is faulted. There are five types of faults that will cause output
LEDs 1 to 18 to flash. These are short circuit, over current, back drive, no
power detected at the output pin, and open circuit. There are two types of
faults that will cause output LEDs 19 and 20 to flash. These are short circuit
and over current.
That's from the Vansco Owner's Manual off the Alpine Coach Tech Library, section 3.5, where you'll find more useful clues.

On the output side ONLY (don't do this on the input side), you can take each leg of the Vansco output to a relay coil, then tap a separate 12V source, fuse it, and run the plug pin off that thru the switched side of the relay. This removes the backfeed. Parallel relays should be configurable which keep the isolation of the backfeed on the switched side of the relays, w/Vansco current going only to the respective coils.

In reading the Vansco Owner's Manual you will also find admonishment not to place relays in line w/circuits on the input side as they will burn up the input. Most inputs have 12V out from the Vansco which grounds when you operate a switch, and the small amperage of the relay will draw more current than the internal input's "output" can survive. There is another thread here discussing how somebody burned up their brake light input by tapping a relay to run something.

Janet&Sid · 10-18-2010, 04:28 PM

Mike:
Thanks for your reply but the Vansco unit is way over my head and the local people in this area have no idea what it is and I am afraid that what they rig up will do damage to the coach.
I think I had better start over to make the two vehicles compatable from scratch. How did you wire yours?
Sid

EngineerMike · 10-18-2010, 06:04 PM

I took mine to a local shop to figure it out for me. I had my Toyota PU set up to tow two different types of trailers so that was involved in the wiring of tail lights, and now wanted to to it w/tail lights driven by the moho. Then I bought a 7-pin curly cord from Roadmaster prewired w/a 6pin on the toad side (or maybe its a 4? I haven't looked in a while, I just plug it in & check the lights).
Do a search on trailer lights and you'll find several discussions involving the Vansco outputs to the 7pin.

Renipladlo · 10-19-2010, 09:12 PM

J & S - Since it's a saturn call the GM dealer, and ask them if their is control box with a harness and this might fix the problem. I did use a test light to determine the blinker signal and the brake signal, and in that plug (on the back of the coach) they were the same. Check the 7 wire plug and see if the brakes and blinkers are not on the same pin in that plug, mine was. So that is why it worked as I through it should. We have the vansco system as well. Does the saturn have a seperate turn signal light and a seperate stop light type system?

Janet&Sid · 10-20-2010, 12:47 PM

Monty:
Thanks for getting back to me with the info. The Saturn's stop and turn signals are seperate are seperate bulbs but on the same wire on the wiring harness. The coach pin is the same for stop and turn signals but of course bulbs are different. My connecting cable tests correctly and my Saturn wiring when connected to a battery and relays lights the lights the correct bulbs so I am at a loss. I have a call in to a Saturn Dealership but they are no selling new cars any more and have not received a return call as of yet. Thanks again for your help and going to the trouble of checking the pins for me.
Sid

Renipladlo · 10-20-2010, 01:19 PM

Check the owners manual on the coach it has the pin out of the plug. Take a test light and try each pin with the key on, something is amiss here. If the saturn works, the problem has to be in the coach.

bcbowers · 10-20-2010, 01:21 PM

Sid - I wired my Suzuki GV from scratch without much of a problem. I purchased diodes from from Roadmaster. I purchased a 6 - conducctor trailer cable, 6 - conductor recepticle, and quick connect wire end from NAPA. You just have cut into the existing wires on your tail lights to add the diodes and connect the new cable appropriately.

I can provide more details and picture if you need them. Give me a PM.

takepride · 10-20-2010, 11:16 PM

Sid:

If all else fails, take both to an automotive electrical shop that specializes in trucks (semi's). Tell them about the Vansco, but most good electricians will understand the workings and causes of the apparent backfeed.

justimagination · 10-20-2010, 11:49 PM

Sid..................Hook up the toad as normal,have someone apply the brakes in the motorhome while you set in the Saturn, when they apply the brakes, see if either turn signal indicator on the dash of the Saturn light up, if so, replace the tail lamp bulb's in the Saturn. I have seen this before, and it is normally caused from a shorted filament in the tail lamp bulb's. I know you said your Saturn has seperate bulb's for tail & stop, but are fed from the same wire. I hope this fixes your problem, it won't cost you a lot of $$$ to find out. Let me know if it works OK. Good luck, happy trails and travel safe.
David G.