Pick up/trailer light question

[zachp]

This problem lies in my pick up rather than the trailer...When i use my left blinker the trailer lights both flash like i have my hazards on, all the lights on the pick up work correctly, and it works fine with the right blinker as well as the hazards. I own a 03 silverado, I took it to a GM certified shop and they couldn't find anything wrong with the wiring so they replaced two little bulbs on my tail lights because they were out (there's 2 seperate bulbs for each tail light and one of them was burned out on each side), they thought this might have been the problem. So after $4 in parts and $105 in labor I went home and hooked the trailer up and it didn't work right away, but when I wiggled the 7 to 4 adapter they'd start working, but it isn't a guarantee it's going to keep working, i've stopped half way home from the lake and the same thing, left blinker and the trailer lights would both be flashing, wiggle the adapter and they worked fine the rest of the way home.

I know the adapter and trailer work because we used my buddies jeep to pull the trailer and everything was perfect. And i also used a different adapter and hooked up to a different trailer and got the same thing.

[nluchau]

Is this Mr. Poehler? If so Welcome aboard FishingMN.

p.s. Sorry I know nothing about trailer lights. I guess they like flashing though.

[Random guy]

Is the adapter or harness the one that plugs inline or T's into the truck harness or has it been put in by hand/several wires going to different points tapped into other wires. The reason I ask is some makes/models that have the blinkers seperate from the brake lights on the truck such as my Toyota require a diode box to keep the current from back feeding from the trailer and make all the lights flash when you use a blinker. If the diode box is needed and installed it could be messed up. I go through one a year.

OR

You could have a wire freyed or exsposed directly behind the truck the plug jumping power across the pins/ports making the lights go crazy only when the trailer is hooked up.

ALSO

Make sure your trailer is grounded to the truck. Sometimes trailers won't ground through the hitch due to rust or other factors creating odd stuff.

[Capt. Don*]

Most likley the ground circuit in the 7 way on the truck is corroded and has high resistance. The multiple trailer lamp flashing is because it is using the filament in the bulb to ground the circuit, when this happens, the filament will glow. I've had this happen numerous times on Fords and more likley than not, the trailer connectors are made by the same supplier. If you take the 7 way connector apart on the pickup, or can access the wiring on the back of it you will find one or more wires that are green and corroded where they connect to the brass contact blades. Sometimes you can clean them up, someimes you need to replace the traoler tow harness connector.

[zachp]

Thanks for the help guys,

The adapter is one that plugs inline, I've used that and a different one that plugs in line and has the wiring giving it another foot or so of wire, both adapters got the same results. I'm goin to try and take them wires off and get them cleaned up then try it again.

Nick,

Yes it is Mr. Poehler here. I get back from AK tomorrow and will be ready to do some fishing. If you have any days off and wanna go catch some eyes let me know.

I figured i've put enough time in on this web site that i oughtta just join it. Anyway hopefully i get my lighting problem fixed and we can get out fishing, later.

Zachary

[Jeremy airjer W]

Welcome to FM Zachp!!

Does this have the towing package (the hitch and trailer wiring came on the truck from the factory) or is the wiring harness on the truck aftermarket. When you say adapter I assume you are talking about the 7 flat to a flat 4. The second adapter i'm guessing is just a flat four extension harness. If this is correct than I agree with the captain. you need to take a look at the back side of the truck plugin (the 7 way plugin) and look for loose, frayed, or corroded wires)

[Guest]

Before you get too involved in changing out things, clean up your connector contacts as best as possible, and most imprtantly.. disconnect and clean up your ground wire contact points(both on trailer and truck). The ground causes the problem 95% of the time. If the running lights are on and you hit a turn signal and all your lights start *flashing*, its very likely you have a weak ground connection and what is happening is all the lights are fading out when the signal is trying to light up because the weak ground connection cant support the current load.. very similar to when a persons rnning lights will work, but they hit the brakes and the trailer lights go out rather than show brake lights.. the weak ground cant support the extra load.

No guarantee its your problem, but there is a good chance, and its best to get the ground out of the way 1st before doing ANY trailer light work. You cant jst visualy inspect the ground wire, you have to remove it and clean it up, make sure its good metal to metal contact.

[zachp]

Yes it does have the towing package, and yes it is the 7 to flat 4 adapter. As soon as i get home i'm goin to clean up the connectors and hopefully that'll solve the problem, it seems like the issue is close to the adapter because when i wiggle it everything works correctly, just not for very long.

Thanks for the help guys.

Zachary

[Gus]

When you have both back lights blinking like the flashers, do the truck blinkers also all flash?

My 03 silverado has some crazy electrical gremlen. With no trailer hooked up sometimes I get my "hazzards" flashing when I'm using a turn signal. Fustrating as all heck. It's intermittant problem. Just does it once in a while. I can see in my mirrors all my lights are flashing. Anyone know what would solve this? Is it ground? or is it maybe the flasher unit itself? It also bleeds power out the trailer harness. If I hook up a test meter to the trailer light plug with the key removed from ignition, I will still have some power bleed to the harness. Crazy.

[zachp]

Gus,

The signals on the truck work fine, even when my trailer lights are both flashing.

[nluchau]

How bout Friday? I have this day off and going fishing somewheres. Any good lakes around DL you wanna hit? I caught a 5 lb Walleye near Bemidji Saturday.

Let me know if Friday works and we'll go from there.

Sorry to go off topic on your boat trailer thread.

Nick

[Jeremy airjer W]

Hey Gus, I wonder if you don't have a turn signal multi-function switch going bad. Usually the tell tale sign is that the right and left brake lights stop working (the third brake light will work fine) or the flasher button is stuck or the turn signals will not work at all.

[Gus]

Airjer,

Thanks for the tip. I've long suspected the problem has something to do what that part. I may just replace it and see what happens. I'm long out of warranty so it might get a wee bit expensive to let the dealer play with it since it is so intermittant. Right now, it hasn't done it in weeks. Then it will act up a couple times a day for one week and then quit again. Fustrating to say the least.

[nluchau]

Zachary. How bout fishing tomorrow. Call me if you wanna get out. 701-730-4508