Lost trailer brakes and brake lights

[B.G. Smith]

Since the hazard warning lights and turn signals acted up I'm thinking you will find your problem in the multifunction switch. When the hazard lights are activated it bypasses the brake switch. bg

 

[Wiredawg]

OP,

Do you have a multi-meter? You can use a voltmeter of it to check connectors on the schematics posted to see if you're reading voltage and inspect the connectors? You can use the OHM meter to check common grounds and within the connectors as well. You want to do this systematically, but will help isolate your problem. Chasing electrical problems can be time consuming. If I read correctly, this happened all of a sudden, so possible broken battery or ground lead, messed up connector, etc...
I sold my 2002 3500 long ago with the FSMs with it.

EDIT: I had a varmit eat through some wires inside the front of the left fender, might also be a central ground point. You might check there.

Hope this helps.

Cheers, Ron

 

[JKellis]

OP,

Do you have a multi-meter? You can use a voltmeter of it to check connectors on the schematics posted to see if you're reading voltage and inspect the connectors? You can use the OHM meter to check common grounds and within the connectors as well. You want to do this systematically, but will help isolate your problem. Chasing electrical problems can be time consuming. If I read correctly, this happened all of a sudden, so possible broken battery or ground lead, messed up connector, etc...
I sold my 2002 3500 long ago with the FSMs with it.

EDIT: I had a varmit eat through some wires inside the front of the left fender, might also be a central ground point. You might check there.

Hope this helps.

Cheers, Ron

Quick update - Back in September I had the bed repainted. The body shop unbolted the bed and slid it back. Yesterday got under the truck and found the wire harness for the left tail light assembly pinched between the bed and frame! I soldered in a section of the four wires that were crushed. That and another new hazard fuse gave me working running lights and turn signals. Today I replaced the brake light switch at the pedal and now I have brake lights. The hazard lights still don't work. When I got the hazard switch I can hear a faint click under the dash that sounds like I'm getting power to a faulty flasher. If the hazard flasher is separate from the turn signal flasher then that's probably it. If not, then it looks like a new multi switch in my future. I just wanted to follow up and thank everyone for all the help. TDR is a lifesaver when it comes to these old trucks!

 

[JKellis]

Quick update - Back in September I had the bed repainted. The body shop unbolted the bed and slid it back. Yesterday got under the truck and found the wire harness for the left tail light assembly pinched between the bed and frame! I soldered in a section of the four wires that were crushed. That and another new hazard fuse gave me working running lights and turn signals. Today I replaced the brake light switch at the pedal and now I have brake lights. The hazard lights still don't work. When I got the hazard switch I can hear a faint click under the dash that sounds like I'm getting power to a faulty flasher. If the hazard flasher is separate from the turn signal flasher then that's probably it. If not, then it looks like a new multi switch in my future. I just wanted to follow up and thank everyone for all the help. TDR is a lifesaver when it comes to these old trucks!

A new flasher fixed the hazard lights and now everything works again. Thanks everyone for all your help.

 

[DavidC]

A happy ending. Glad your fixed.

 

[Wiredawg]

A new flasher fixed the hazard lights and now everything works again. Thanks everyone for all your help.

And now YOU are the electrical expert.

Cheers, Ron

 

[HPSimpson]

And now YOU are the electrical expert.

Cheers, Ron

Ron, Is very good at electrical problems, great person to help solve the mystery electrical issues!

 

[JKellis]

Ron, Is very good at electrical problems, great person to help solve the mystery electrical issues!

I am very thankful for Ron. Personally, I would rather have a root canal than deal with electrical issues.

 

[Wiredawg]

I am very thankful for Ron. Personally, I would rather have a root canal than deal with electrical issues.

I hear ya brother... my nemesis is plumbing, bbt I still tackle it. I have three 1660 gallon water storage tanks i plumbed together to catch and use rainwater coming off my shop... Pesky leaks have me looking at rubber flex fittings to remedy the bad angles. I'll whoop it though just like you did.

Congrats on your victory.

Cheers in your beers, Ron