bad ground/water?

pootnic

Chief Petty Officer
Joined
Aug 11, 2007
Messages
447
Trailer lights work fine as long as i dont put my headlights on.Ive never noticed before;last night was the first time trailering in the dark.Maybe they never worked with the headlights on not sure but the trailer is inspected.
When i launched my boat:
- i unplugged the connector
-the trailer lights do get submerged(there not water proof ones)
After i trailered my boat:
-waited probably 15 minutes before i plugged the lights back in
-noticed my truck tailights brighter than normal
-the running lights where bright,like brake lights
-applied the brakes they went dimmer on the trailer
-turned the blinker on both sides blinked kinda like hazards
-no fuses or bulbs blew
Maybe the water just messed things up for awhile,should i be looking for a bad ground or do i need a bigger relay or something like that in my truck?
My truck used to blow the 15amp fuse(not the relay)earlier in the summer;it fixed itself(smart truck i know).When i turned the headlights off everything worked fine.
Thanks for any replies..John...this is my thrid time trying to post this keeps saying im not logged in..grr
 

mrfixitman40

Petty Officer 1st Class
Joined
Aug 13, 2007
Messages
286
Re: bad ground/water?

sounds to me like a ground is your problem and it is back feeding through the other lights
 

pootnic

Chief Petty Officer
Joined
Aug 11, 2007
Messages
447
Re: bad ground/water?

its gotta be a bad ground on the trailer but:
-trailer less than a year old(know that doesnt matter)
-visually checked all i could(wires seem fine,no frays)
-removed all lights tested to trailer frame(+ white wire)all open
-with the lights out tested between the two stripes they where open
so i go to the truck;really dont want to remove all the lights so i check the voltages they seem fine only one side blinking at a time and when i turn the headlights on theres a solid voltage for the running light and only one blinking like it should for the blinker....go to plug it in works fine headlights off;go and put them on act nuts blinking like hazards and stuff.
Must be the trailer ground right??
Is there an easier way of checking the ground on the truck(with all the lights in i checked the white to my bumper and trailer ball it was shorted,so where the other wires but im hoping thats because the lights where still in)
 

wire2

Lieutenant Commander
Joined
Jun 25, 2007
Messages
1,584
Re: bad ground/water?

A poor trailer ground would have no effect on tow vehicle lights.

Ground is probably ok.
The 2 filaments are shorted together by water. Now there's power to the bright filaments from the dim filaments circuit and vice versa.

It will make all sorts of weird (but predictable) things happen on the trailer AND tow vehicle.

Remove the trailer's dual filament lamps, then check for continuity between the brown, yellow and green wires. They *should* be open. If not, there's either water or corrosion shorting them.
 

luckyinkentucky

Chief Petty Officer
Joined
Jul 29, 2007
Messages
462
Re: bad ground/water?

In the future you could take some 'Liquid Tape' and seal the lights up, or just buy waterproof lights. You can find Liquid Tape at most any hardware or auto parts store. I know Wal-mart has it in the boating section in sporting goods.

I did this to one of my utility trailers that I haul dirt bikes on. I sometimes go down muddy / wet roads, and hit a lot of ruts and potholes full of water. It saved me at least $30 by just buying 2 bottles of Liquid Tape and sealing the cases, and making sure all of the connectors had heat shrink butt connectors on them. you can also use some Marine Adhesive Sealant 5200 to seal back behind the light where it affixes to the trailer. This adds a little extra reassurance. Considering most electrical wiring these days is rubber or plastic wrapped, you don't have to worry about the wire itself too much. Just the connections. You could probably 'waterproof' your trailer in an afternoon if you wanted to.
 

wire2

Lieutenant Commander
Joined
Jun 25, 2007
Messages
1,584
Re: bad ground/water?

>>...works fine headlights off;go and put them on act nuts blinking like hazards and stuff.<<

The headlights are blinking? That happens only with a short to ground on the headlight circuit. A breaker will trip, reset, trip, etc.

Are your truck lights ok with the trailer plugged in but no lamps installed?
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: bad ground/water?

You are missing a very important clue! Trailer lights (running lights) cannot work unless the headlights are on. You said the trailer lights work normally until you turn on the headlights. Where do you suppose the power is coming from to light the trailer lights if the headlights are OFF? You best make sure the truck is wired correctly before blaming the trailer. If the truck isn't right, there is no way the trailer can work correctly.
 

wire2

Lieutenant Commander
Joined
Jun 25, 2007
Messages
1,584
Re: bad ground/water?

>>You are missing a very important clue! Trailer lights (running lights) cannot work unless the headlights are on. >>

Well, yes they can. On parking lights setting.
Headlights and running lights are 2 independent circuits.
 

pgdignan

Petty Officer 2nd Class
Joined
Jul 31, 2007
Messages
142
Re: bad ground/water?

I wired a plug for trailer lights last year that required some sort of voltage isolator thing. Similar to what Silvertip is saying, your problem is likely with the truck not necessarily the trailer, if turning on the headlights causes demonic possession of the trailer lights, look to the truck wiring.
 

pootnic

Chief Petty Officer
Joined
Aug 11, 2007
Messages
447
Re: bad ground/water?

first off thanks for all the replies...
i hope i didnt confuse anyone with my earlier explaination:
with the headlights off everything works fine(truck,trailer)
only when i turn the headlights on do the weird symptoms happen and only on the trailer.:
-put either blinker on and the other side will blink also,not at the same time(i say that because when the hazards are on they blink at the same time...i hope that good)
-when i put my brakes on the lights stay on but go dimmer
those are the two symptoms that i seem to be dealing with
i going to try tonite to hook up an external power supply to see what happens without the truck being there...but im not going to get the flashing because it will be a solid 12v's...think ill try my truck on my dads trailer as well that would be smart also
thanks again ill let you know how it goes
 

pootnic

Chief Petty Officer
Joined
Aug 11, 2007
Messages
447
Re: bad ground/water?

its my truck...hooked up to my dads trailer and it did the same thing...
its crazy though;had my multi meter plus dad had a tester with lights that you plug into the connector...when you turn on the headlights with a blinker on everything reads fine...
i found some bare metal on my bumper and tested to see if my ground was shorted to there and it was...but so where the other wires;im hoping thats because the lights are still in my truck
can someone tell me or show me a link on how to check to see if my truck connection is right
the guy i bought my truck from had a fifthwheeler,all i did was cut that connection of and splice in my own connection...howd i ever get this thing inspected;must of did it from day one;probably because the light thats not supposed to blink, blinks weaker than the one that turned on.
 
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