No brake lights

[true74yamaha]

I have a 1985 Chevy k10 I just ran in to a problem. My horn wasn't working ended up being the relay rusted out horns and short in the column. Now after replacing my turn signal switch I now have no brake lights.  My trucks running lights all work headlight low and high beams and all turn signals right and left work with the headlight on or off.  But I have no brake light or come to find out no hazards which is weird because I thought I checked my hazzards after installing my new turn signal switch and they worked... I'm not sure what could be wrong or where to start. I know these trucks are known for bad grounds.  That reminds me my truck did have a problem where it was has an intermittent short in the left brake light where it wouldn't work.  And ideas on some guidance on where to go with my truck would be much appreciated. Please and thank you. 

[true74yamaha]

Any ideas

[bd]

Check the stop lamp fuse.  It also powers the hazard lamps.  If the stop lamp fuse is good, try swapping the turn signal flasher with the hazard flasher to see if the hazards start working.

The stop lamp switch feed into the turn signal switch is a white wire.  Make sure the turn switch is completely plugged into the factory harness under the dash and that none of the wires were pushed back out of their connectors.

[Joec123able]

The last time I had a similar problem with my 87 r10 it ended up being some brittle wiring not making a good connection back behind the bumper where all the wiring meets.

[true74yamaha]

Sounds awesome sounds like I have some ideas to go on where to look thanks

[true74yamaha]

I tried swapping relays it didn't make the hazzards work. But it showed me though that the hazzard relay is still working. The way i concurred this was with them switched the turn signals still worked while using the hazzard relay.

[true74yamaha]

I can't beleive I didn't check my fuse in the fuse block. I checked the turn/hazzard fuse and it had been over loaded and blew. I didn't not have any 15 amp fuses so I checked to see if a 20 amp would tell me anything and it blew as well.  I do have some corrosion on the grounding screw behind the taillight housing. I am going to go get a wire brush attachment for my drill and see if it will make a difference. It will obviously help no doubt.

[bd]

You should clean up that corroded ground connection using some emory cloth, but a bad ground won't blow a fuse! 

In your original post, you stated that all the turn signals work.  Did that change?  Do the turn signals still work?

When does the fuse blow?  As soon as you install it?  Only with brake application?  Only when the hazards are energized?

[Eastonfrench]

I had the same issue this weekend on my Chevy. Listen:
TO blow a fuse means youre overloading the circuit. This means somewhere you have a short. A short means you have some exposed wire touching metal somewhere.
In my case, the wiring going to the rear lights had fallen down onto the exhaust, and the casing on the wires had melted off, exposing the wire.

Crawl underneath the truck and visually inspect the wiring from the brake lights to the cab. if there isn't anything there, pull both taillight assemblies out and check the wiring behind them for breaks. After that, see if the stoplight switch is shorting out. You can bypass it if you want to check it. (the brake lights will always be on).

One of these issues is almost surely what youve got. A cheap fix, but a pain to find

[true74yamaha]

Well was able to figure out my problem.  Mine was where it lookes to be an extra set of factory tailer lights that were added. They used some squeeze type splice connectors so the wires were getting corroded on the splice connector.  I'm glad I was able to figure out my problem. for temporary I just used tape to cover the old splice job. What I was thinking about doing is cut and solder the factory wires back together and use some heat shrink on them along with some siicone.. Some one told me I should use s dab of silicone on the soldered wires before I heat the heat shrink that way when I heat it i will have a moisture tight barrier because when the it compresses the silicone will be forced out.

[bd]

Before attempting to solder the splice, clean the copper strands to shiny bare metal then use 60/40 rosin core solder.  Avoid silicone.  Silicone contains acetic acid.  Acid corrodes!

Instead, use an adhesive lined, double wall, polyolefin heat shrink.  Harbor freight sells it under part number 67598, as does Del City, et al.