Ok hello..I never try to post things on fourms but I'm beating my brains out trying to figure this out. I have a 95 ram 1500 4x4 318 and I am having a brake light issue. The brake lights work fine so long as I do not have the head lights or park lights on. If I turn on my lights the rear lights go out when I hit the brake I've read others have this issue and fixed it by replaceing the mfs (turn signal switch/high beam /wipers) I did this but still same problem .. my third brake light works fine no matter what (one on the back of the cab of the truck) turn signals work as do the 4ways. Fuses are fine as well could it be the head light switch? Also there is no connector for a trailer so no short there and I did not see any ground wires back there. Please help its getting cold and this is the only thing I have to get around in the snow. Some one please help or atleast guide me in the right direction. Thank you

 

sounds like my old Tundra which had the same problem on the drivers side only. The solution was to replace the body harness. Now I own a Ram. You could replace the light switch with one from a bone yard and see if that works but my bet is either a short in the harness or the plug has massive corrosion and is traveling up the wires. I would do the switch first as that would be the cheapest fix then go from there.

 

For some obscure reason, the ground for the rear lighting is...... up near the horns..... Take a look at the ground there, clean it up, make sure its good.

If that doesn't help, pull the headlight switch, and see what ya got on the connector. They like to melt..... bad things ensue.

 

Thanks for the fast replays ill try and take a look at the grounds again I already fixed the upper ground up front ill check the lower one aswell. Ill just buy a new head light switch and put it in today. Thanks again.

 

Ok so I just took out the head light switch. There is no signs of melted or burnt wires and the connector looks fine I will still replace the head light switch. There is two bare wires buy the lower ground on drivers side wheel well its green and a black one no idea some o e put a aftermarket horn with a button on dash and a electric fan with a switch. So could be unused wires for original horn maybe.

 

So I replaced the headlight switch. Still solved nothing I do not see any broken grounds or melted burnt wires. Im baffled its so odd that they work as long as the park lights are not on....

 

Still indicates a bad ground somewhere.....

Turn on the park lights, have someone step on the brakes, (or, put a big brick on the pedal....) and test and see that you are getting power in all the appropriate places on the bulb socket. See what ya find.

 

I have yet to try that. I need a bit of a brake from it today I did find out that if I unplug the 15amp fuse for the park lights and turn the head lights on the brake lights will work. So I beleave its deaf on the park brake circuit.

 

Ok I busted out the multimeter at the rear bulb socket the green wire has 12v the middle black and yellow has 4v and the ground wire has 11.3v that's with the park lights off and brake on. Now with the park lights on and the brake on all wires at the socket have about 12v. Soo I'm assuming this tells me there is a short on the ground wire. But why did it not blow a fuse? Is there any key locations to look for this short? And with just the park lights on green wire has .6v middle black and yellow has 12v and the black ground has 1.5v

 

You have a short somewhere..... usual spot is where the trailer harness connects... if you have one..... if you don't, think I would just follow the harness by hand/eye, and see if it isn't just pinched somewhere.... like, if someone dropped the gas tank, and then caught the harness when it was reinstalled.....