No Hazards or Brake Lights

[Dave01]

I was working on trailer lights and shorted something out. The trailer is not connected and here's what's happening:

taillights and directionals work
no hazards
no brake lights

I checked the 30 amp fuse under the hood, the brake and flasher fuses on the left dash panel, all are good. I swapped the 2 silver relays on that same left dash fuse panel and same result. What did I fry?

 

[Turbine Doc]

I would suspect the tail light fuse in the interior panel IIRC 25A (yellow) I carry spares with me for mine, gnd for trailer has to be good, or they put extra load on the tail light circuit and the fuse pops

 

[Dave01]

Glad you made me look again. The #1 fuse, for hazard and brakes, was fine, but the block it plugs into isn't making good connection. So, when I wiggled it the hazards came back. I'll have to see if I can clean or tighten it tomorrow.

I'm sure you're right about trailer ground. I'm one of those people who can't keep trailer lights working if my life depended on it, just seems to defeat me. What's the best way to improve the ground, run a separate wire from trailer frame to truck frame?

 

[Turbine Doc]

yes I made a dedicated extra gnd pigtail for my trailers with these trucks one can never have too many gnds IMO and do this annually if you can http://www.thetruckstop.us/forum/showthread.php?t=17457 or at minimum check with meter to make sure gnds are clean there is a good product I have been using for gnd maintenance http://www.corrosionblock.com/ you can get it at boating suppliers

 

[DieselCash]

On my truck;

If you push and hold the hazard switch in, the hazards work great.

If I let it go, nothing works. The brake lights, blinkers, and hazards do not work.

I talked to my brother about this and he told me it was common for the hazard switch to go out.

My hazard switch is the black push in, pull out on the steering column.

When I get back I need to get that switch fixed.

 

[Dave01]

I got them working OK, then the fuse blew again when I hooked up the trailer. Obviously I have a wiring problem, this happened even after adding a ground wire to the trailer as TD suggested. I know this is not a good idea in general, but I replaced the 20 amp fuse with a 25 and it held, I'll work on the trailer lights and hopefully fix the real problem.

My hazard switch is the one on top of the column, push it and it pops out to go on, push it back in to turn off. It seems to be working fine.

Its interesting what is on different fuses. Fuse #1 that blew was not only stop and hazards, but also ignition and door beeper, rear hatch release.

 

[Turbine Doc]

Gnds on the trailer itself possibly, something is making it pull high current and blow the fuse.

You had 20A fuse ??? IIRC that is supposed to be a 25 A yellow fuse, I'll check mine later to confirm, quite possibly the p/o only had a 20A and you were undersized ?

 

[540s10]

Gnds on the trailer itself possibly, something is making it pull high current and blow the fuse.

You had 20A fuse ??? IIRC that is supposed to be a 25 A yellow fuse, I'll check mine later to confirm, quite possibly the p/o only had a 20A and you were undersized ?

my 97 says 20A for the hazards/brake lights

 

[Dave01]

I checked, the sticker on the fuse door says 20 amp, same as yours. I've never had the problem before so I know its the trailer lights. I have 4 trailers and 3 of them could use a complete re-wire, I'll tackle the one that caused the problems first.

 

[Big T]

You've got a short in the trailer wiring. Probably one of the brake light wires is frayed and shorting out on thr trailer frame, thus blowing your fuse. I have 2 boats, one dunked solely in salt, so speaking from just a bit of experience.