Trailer brake issues

[James McClure]

Morning everyone. Problem, trailer brakes pulsate (apply then release) when 4 way flashers operating. Brakes, electronic brake controller and all lights function as they are designed. I know what the cause is (4 way flashers use the brake light circut, not the signal light circuts) I thought of several different ways to beat this, but all of them are rather cumbersom or draw to much current. I thought of using a switch to stop the backfeed into the controller to kill brake imput, but then I wouldn't have trailer brakes when the 4 ways were on. I thought of using a relay but the added load of the relay coil would strain an already loaded circut. My last idea was to use a diode to stop the backfeed into the brake light circut and still have the trailer brakes operate normally. Diode has to be able to handle at least 10 amps, 15 or 20 would be better. Question, does anyone know where I might locate such a diode? Radio Shack isn't any help and the trailer place doesen't even understand the problem. Many thanks, Jim

[jimfulco]

Why are you driving with the 4-ways on in the first place? The semi-conscious people driving behind you won't notice that you've hit the brakes until the brake lights have quit blinking for a couple of seconds, and they'll hit you from behind.

[James McClure]

Originally Posted by jimfulco

Why are you driving with the 4-ways on in the first place? The semi-conscious people driving behind you won't notice that you've hit the brakes until the brake lights have quit blinking for a couple of seconds, and they'll hit you from behind.

I drive with the 4 ways on when I'm out on the interstates when my speed drops below 50 miles per hour. It's force of habit. I used to drive 18 wheelers and D.O.T. regulations require vehicles with commerical registrations to follow this rule. Watch any 18 wheeler pulling up to a toll barrier and leaving it or watch one pulling a long grade and moving slow and you'll see. I don't know where you live but I live in upstate NY and travel in Masatwo****s, Vermont & New Hampshire and they have some serious mountains. I90 across NY & Mass are loaded with big ones and I89 in VT or I83 in NH are 2 more. I90 is the most fun though because the cops leave the big trucks alone pretty much. Jacobs ladder over in MA on I90 is a killer hill. It's 6 miles to the top and if you can break the crest of the hill at 45 MPH your doing good. Going down the other side is a blast!! There is noplace for the cops to sit to get you on radar and the road is pretty straight, only slight turns and at 3:30 or 4:00 in the morning there is no one out there. It's the ultimate RUSH 100,000 pounds of truck and flour at over 120 MPH, engine screaming, tires screaming and the sterio full blast. YES!!! P.S. don't screw up at the bottom, there's a bridge there over a gorge 900 to 1000 feet deep!!!
Have fun out there and if you see a big red Freightliner behind you and all you can see in your mirror is grille and flames are shooting out the stacks GET OUT THE WAY Paladin's commin' thru.

[boxrodz]

I've noticed truckers driving their flashers on when they'll 'crawling' up some of the mountain grades here in Colorado. I've also noticed some vehicles in tow with their flashers.

I must have came across your brother on 285 between Fairplay and Denver last year. He was flying when he past me. He was really moving especially for mountain, deer crossing and nighttime driving. Talk 'bout carving curves in an 18 wheeler ...

Interesting concept of isolating the brake signal from the flashers. For diodes, check out the electrical parts at your local RV/Marine Shop. They use 'heavy duty' diodes for protection in power backup systems. Here's a link (http://www.dan-marc.com/rv-parts-electrical-diodes.html) from a quick search. You also might try Jameco (http://www.jameco.com) or Digi-key (http://www.digikey.com/).

[Mickey_D]

What you could do is run a wire directly from the brake light switch to a relay and use that to control the trailer brakes. That circuit is already isolated from the 4-ways and turn signals.

[James McClure]

Morning guys: I got the cure ordered. It's an isolating diode made specifically for the problem I'm haveing. Thanks for your imput, Jim

[1984 swb chevy]

I had the same thing happen to me. I didnt find out until I had a problem with my trailer and had to use my 4 way flashers. When my flashers would flash the trailer brakes would lock. I found that when the hitch and plug were installed by a trailer company they did a crapy job and the wires were touching the wrong poles inside the pug. I cleaned up the connections at the plug and never had a problem with the brakes. I did have damage to the motorcycles I was hauling and the trailer company had to pay for the damages. I hope this helps