I'm at a loss here. Brake lights and rear marker lights don't work. I've tested the brake lights switch and it works (circuit completes on brake pedal depress). What's the next place to test with my multi-meter. The two wires from the brake pedal switch enter the harness and not sure where they go next. Checked fuses and they're good.

I also pulled the round Hazard Flasher thing that says "#536 Heavy Dudy 12V 1-5 Lamps" is this a relay? How do i test this? Is this a relay?

Help very much appreciated!

I have the electrical diagrams and can't make sense of them need some plain speak.

 

Do your turn signals/emergency flashers work?

 

Emergency flashers don't work. When I hit the turn signal the turn light indicator on the instrument panel stays solid.

 

Sounds like you have a couple things going on...Not to be a smart aleck but have you changed the rear bulbs? Check the front turn signal bulbs as well...if one is blown it could cause the indicator to stay solid for that side.. Also I would change the flashers (they are pretty cheap). Check the sockets for power...I have one reverse socket that is missing the ground terminal so that light doesnt work.

 

Just to try to give you a rough idea on how it works. Power from your brake light switch goes to the turn signal switch. There, it is split or not split depending on position of the turn signal switch. If turn signal is in the center it sends the power straight to both tail light housings. If turn signals switch is up power is split. Power goes straight to the left tail light for a solid brake light and power is sent thru the flasher relay and flashes the right tail light. Good luck.

 

I agree with wilcam47; as a first step I would make sure the bulbs are good.

 

Im gonna grab new bulbs tonight but I have tested the sockets with a multi-meter and the tail lights get no power regardless of what I do at the turn signal switch or brake. I'm thinking maybe a turn switch issue?

 

That's certainly possible; another possibility is the bed having lost ground. Do the license plate lights or tail lights work? If there is absolutely no lighting from the bed at all, I'd suspect a ground issue - otherwise I think you're on the right track.

 

I have seen turn signal switches cause this . But as stated above , ck for proper ground first . Also ck the plug at the bed for corrosion . One last thing , do you have a trailer plug ? I have seen many of those cause this issue where they connect to the truck . I have also seen dog and rodent chew damage . Just a thought !

 

So there is a trailer plug at the back, it's a yellow square plug that is a male style.

 

Do you have a long piece of wire, one that will reach from the battery to the tails? If so, you can run it from the NEG side of the battery to the screw/ground behind one of the tails and then try everything. That will tell you if it's a ground issue. You can take your turn signal switch out, clean it and it will work a ton better if that ends up being the culprit.

 

Check where the trailer plug attaches to the truck wiring . Ck for broken or corroded connections . Those little scotch locks cause a lot of issues , So does just " twist n tape " I would start there . I see that a lot on farm trucks , farm dogs get board , and like to chew . So do rats !

 

Dont quote me on this but being that all your lights are not working on the back of the truck, its possible that the connection (PLUG) that is in the engine compartment may have come apart. On my truck there is a plug approximately under the Master Cylinder on the inner fender (Drivers Side) where all your lights go through as a connection for the rear lighting harness. I can take a picture of mine if it will help. Im wondering if maybe you might have a problem in that harness connection. Its just wierd that all the lights on the back of the truck arent working..

JRB65

 

Mine has a similar plug at the rear of the frame that connects all the bed lights to the truck . That was the plug I mentioned earlier .

 

You guys are fantastic thank you for all the help! I hate getting stumped by this stuff and you guys are spurring me on! I picked up all new fuses, bulbs, and a test light. I figure I can test all the connections in the engine compartment to make sure power is getting there. I tested the non-trailer plug connection at the rear (one that plugs into the rear lights harness) and it wasn't getting any power no matter if the headlight switch was on or not or if the brake was depressed or not. I'm going to take a bunch of pics maybe that'll help you guys help me!!!