Ground Problem?

campclanlouisa · 07-17-2010, 05:28 PM

My Brake Controller has a red light which indicates it is hooked up. While I am stopped or going slowly the light is on as I pick up speed it will start to flash periodically then it may go out for awhile ( no trailer brakes when this is occurring) then it may come on when a vehicle passes me. I have marks on the ground blade on tow vehicle which indicates a loose ground somewhere. I can't find where the ground is located on the trailer. Should it be back by the axles? I checked the junction box near the tongue and no loose connections. I have tried moving wires on the truck and my trailer plug to get the light to flicker to no avail. Any suggestions?

Tow Vehicle 2006 Chevy Tahoe 5.3
Trailer 2008 Flagstaff Classic Super Lite 829 BHSS

jimh · 07-27-2010, 08:13 PM

if there is any way, check the supply voltage to the controller when the controller light goes out. the first one that i installed called for a circuit beaker between the supplied voltage and the controller.
If you have no voltage, then u will have to determine why. the controller may have a problem.

ground problems do interesting things. do the lights work ok on the trailer? do the turn signals alternate from one side to the other? I'm thinking that if u had a bad ground, it wouldn't show that the trailer was connected (guess it depends on the degree of disconnect.

check the ground at the (or to the) wheels. u may have a problem there.

i'm leaning more to a bad controller or a short circuit.

i would tell u to disconnect the controller in the viehicle then, with the trailer connected, check the ohms between ground and the brake control output. (i would always check voltage first between these pts just in case i was on the wrong pins. then if none found would check resistance. if i knew what the resistance should be, i would tell u to try this. unfortunately, i don't know what to expect so won't tell u to try this.

you could try hooking ur tow viehicle to another trailer or vice versa and see if the problem is still there. if it is, the problem isn't the trailer.

u may even have a bad circuit breaker.

if u can't tell, i am picking at straws. this is perty much the approach i would take if it was mine.

Fire Instructor · 07-27-2010, 08:27 PM

Back-up to the trailer, but don't connect the hitch (don't even touch). Then plug in the pigtail and see if you have lights. on the controller. Sounds to me like you may be gounding through the hitch (metal to metal) and not by the wiring harness. This will give you intermitant connection.

LadyWindrider · 07-27-2010, 08:38 PM

Marks on the ground terminal DO NOT REPEAT DO NOT indicate a ground problem. It only indicates a problem, as all the power between the tow vehicle and trailer travels through the ground lug. This includes brake current, light current, (running lights stop/turn signals),charging current for the trailer battery. A burned ground terminal indicates some kind of overload, but finding where it is will take some electrical detective work. The brakes do draw the most current, usually, unless you have a lot of running lights at 1 amp each.

Since your problem seems to start with wheel rotation, I might pull the trailer wheels and check the brake magnets and make sure one or more of them hasn't worn through and is shorting out to the brake drum. Just a thought.

campclanlouisa · 07-28-2010, 03:42 PM

1st off I do have running lights no matter if Brake Controller is working or not. Signals , Brakes and running all light up and work properly. I tried plugging in Trailer without hooking up hitch and found the light was out, unplugged and replugged and light came on. Tried another Trailer and the same thing happened. I am guessing my problem is not in the trailer and I will check my controller and harness to my vehicle this weekend. I really appreciate the help. By the way the is a plug and play unit no direct wiring.

campclanlouisa · 08-01-2010, 06:20 PM

Well, I have replaced the Trailer plug, added an additional ground on the trailer. I also checked all the magnets and wiring to the brakes on the trailer and unplugged and checked to wiring to the brake controller. I also was able to hook up to another camper and the problem was still there. Upon inspecting the old plug I found that the 12V contact has marks that indicate arching. I don't have a meter to test the output of my brake controller so I am not sure what I should do next.

LadyWindrider · 08-01-2010, 10:14 PM

Well, now you know that the problem is in the tow vehicle. If you have those blue connections, the ones where the thin metal strip mashes through the wire insulation, GET RID OF THEM!!!!! The best connection would be to remove the insulation on the wires, add heat shrink tubing on one of the wires, solder the connections, then cover with the heat shrink and shrink it down. Once you have the controller nailed down, take the plug apart on the tow vehicle, especially if it is aftermarket. If it is factory, may be sealed.

As for a meter, do you have a 12 volt test light? Many times this is enough to check brake wiring. Good luck.

Iggy · 08-02-2010, 08:40 AM

Time to find a professional to check your tow vehicle wiring to the rear.
Who originally hooked up the brake controller?
Was it OEM installed or installed by someone down the street?
Quit wasting time and find someone who know electrical systems.

I think it is just a bad connection or a lose or no proper ground wire from truck to trailer.

jimh · 08-02-2010, 04:47 PM

which connector did u replace? the one on the trailer or the one on the truck?. on my first trailer, my brakes wouldn't work and it turned out to be a loose connection (plug was not making contact with the truck) in the 7 way plug. we bent the plug pins slightly in (i believe this is the one on the trailer) connection was restored and all worked. you may want to try this. i wouldn't fool with the one on the truck (as far as bending terminals but that is because that exceeds my comfort zone). when i say slightly, i mean abt 1/16" too much and the plug won't go into the resciptical.

no matter what, try the suggestion above abt getting rid of those little blue splice connectior. those things are nothing but a headache.

if all else works and the brakes work, it is sounding more like one of those splices or connectors not making in the plug. you may be able to zero in by pluging in the trailer and wiggling the plug and see if the light flickers on the brake controler or if light is out, see if it comes back on.

i'm inclined to believe that if all else is working, the connector is probably not making contact. could be pins aren't contacting or it could be the splices not making contact.
the contacts on the truck side fold over to form a spring so that they push tightly against the pens in the trailer plug. take a look and see if the fold overs on contacts are all in tack. these may have compressed some from use and are no longer holding a tight fit against the trailer plug. moving the contacts in slightly on the trailer plugg should at least tell u if the problem is in the connector. if this works, u may then want to adjust the connectors on the truck or replace that connector.

WD-40 can work wonders for corresion. spray the contacts then make and break them a few times to adgitate the corrosion.

campclanlouisa · 10-19-2010, 10:05 AM

Problem Solved!! This is just an FYI reply. The problem turned out to be in a factory connector located under the hood near the fuse box. As I would travel air would cause the wire connector to loose contact. As Trucks would pass the negative air pressure would cause wire to move in opposite direction which would cause light to flicker on/off. I cut out the factory connector and spliced wires together with dielectric grease and waterproof butte splice. Drove back from NY without any problems.

jimh · 10-19-2010, 11:08 AM

i'm glad u found it. seems no matter what problems we've had in the past, there is always a new one.

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