99' Silverado Trailer Wiring Puzzle...

[dhartles]

I have a 99' Silverado WITHOUT the tow package. I recently bought a boat, and need to rig the trailer lights harness. I bought a Hopp y 4 flat connector and spliced it onth the provided wire bundle the rests on top of the spare tire. Pretty easy I thought yellow to yellow, brown to brown, green to green and white to white......yeah right.

When there are no keys in the ignition and I press the brakes, the brake lights on the trailer work. However, running lights and turn signals do not (as I would expect). However, when I start the engine, the running lights on the trailer come on, and now the turn signals on the trailer work, but when I press the brakes, ALL of the trailer lights go out. At first I thought I had a bad ground, but the brake lights on the trailer work when the engine isn't on, so that can't be the case....dazed and confused, please help.... I'd like to go fishing this weekend....

Thanks,
Dave

[Moose is loose]

Mine did not come with the factory tow package either however, it did have a receptacle/plug above the spare that was factory. The Hoppy harness that I bought had the female end that just plugged right in. Maybe yours has that plug, or maybe it has just a wire loom. I don't know, but if you have the round plug from the factory above the spare, Wal-Mart sells the plug/harness for around 25.00.

[dhartles]

Yeah, mine just has the wire loom. I just can't understand why all the trailer lights go out when I press the brake. I even checked all of the trailering fuses in the fuse compartment under the hood last night, and they are all fine. I'm about at the point where I'm going to take it to the dealer...ugghhh..

[sportin83]

it sounds like you got a wrong ground wire. where is it grounded? check that.

[99redsilverado]

check grounds.....and also there is the wiring diagram in the owners manual as far as what wire does what...

[z7one]

I have a 99 silverado and was having this same exact problem. My silverado did come with the towing package. I started with the wiring on my trailer and everything checked out so I got out my ohm-meter and started troubleshooting with the ground on the electrical recptacle on my truck. I started with the white wire (ground) and it was open to frame ground......So then I ohmed it out from the pin on the outside of the reptacle to the white wire in the wiring harness right behind the recptacle ( I poked the probe thru the insulation) and it was open also, which suprised me.......I disconnected the wiring harness from the receptacle and to my suprise there was corrosion on the terminal on the back of the receptacle...The ground pin is the one on the bottom and what had happened is that water had gotten in there and it was just enough to only get the bottom pin wet and corrode it....I cleaned everything up, connected it back together and everything works great now!!!!!!!