RottenSS Posted March 16, 2015 Report Share Posted March 16, 2015 So my truck is being goofy electrical wise. I hit the brakes and my front turn signals light up. I haven't messed with anything lately. It did rain crazy hard yesterday and I did also tow a boat for my friend and when I plugged the boat in the trailer didn't have lights. Could be from my truck. I checked a few fuses that I thought might mess with it. Any ideas? Online says flasher relay possibly or bad ground some place. Quote Link to comment Share on other sites More sharing options...
MID12sSSS Posted March 16, 2015 Report Share Posted March 16, 2015 So my truck is being goofy electrical wise. I hit the brakes and my front turn signals light up. I haven't messed with anything lately. It did rain crazy hard yesterday and I did also tow a boat for my friend and when I plugged the boat in the trailer didn't have lights. Could be from my truck. I checked a few fuses that I thought might mess with it. Any ideas? Online says flasher relay possibly or bad ground some place. I dealt with something like this last week. It was an 07 (I think) Avalanche. The left trailer brake didn't work, but everything else did. The left trailer brake used the same exact circuit and fuse as the left trailer turn signal, which worked fine. After studying the wiring diagram, I found a 10pin module that plugs into the back of the fuse box that's just inside the drivers side dash panel. Remove the lower panel below the steering wheel. Then there's a brace I also had to remove that shrouds the steering column. Then just to the left, there is a black rectangle (like I giant relay) that plugs into the fuse box. This relay interprets driver input, then provides output voltage to the proper circuit. So when you demand left turn, it'll pulse voltage down left brake circuit. That's why my left brake light didn't work, but left turn did... If that makes sense. Replace this "LCM" and you should be golden. Come to find out It's a common problem and a fairly inexpensive piece... This is my .02 of advice.. I can try to track down the part number if it helps. Quote Link to comment Share on other sites More sharing options...
RottenSS Posted March 16, 2015 Author Report Share Posted March 16, 2015 Yeah so you're talking about replacing the flasher relay. I didn't look if the back turn signals come on when I hit the brakes but I know the front 2 do for sure. I'll try a relay I guess. $35 dollar part online. But yeah like I said when I hooked this boat up the trailer had no lights at all. Not sure if it's my truck or the trailer since my friend just bought the boat and that's also the first thing I've hooked up to it. Just not familiar with wiring and wasn't sure if maybe hooking that up could have caused an issue some how. Quote Link to comment Share on other sites More sharing options...
MID12sSSS Posted March 16, 2015 Report Share Posted March 16, 2015 Well, i believe the flasher relay and the LCM are 2 different pieces... See if you can figure something else out, but without being able to run any tests myself, that'd be my guess Quote Link to comment Share on other sites More sharing options...
Downeast Johnny Posted March 17, 2015 Report Share Posted March 17, 2015 I dealt with something like this last week. It was an 07 (I think) Avalanche. The left trailer brake didn't work, but everything else did. The left trailer brake used the same exact circuit and fuse as the left trailer turn signal, which worked fine. After studying the wiring diagram, I found a 10pin module that plugs into the back of the fuse box that's just inside the drivers side dash panel. Remove the lower panel below the steering wheel. Then there's a brace I also had to remove that shrouds the steering column. Then just to the left, there is a black rectangle (like I giant relay) that plugs into the fuse box. This relay interprets driver input, then provides output voltage to the proper circuit. So when you demand left turn, it'll pulse voltage down left brake circuit. That's why my left brake light didn't work, but left turn did... If that makes sense. Replace this "LCM" and you should be golden. Come to find out It's a common problem and a fairly inexpensive piece... This is my .02 of advice.. I can try to track down the part number if it helps. This could be really useful information. Thanks for posting it Brandon. Hope you get your problem sorted out John. Quote Link to comment Share on other sites More sharing options...
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