Rear brake lights don't work

Does it have spark? And other questions...

Moderators: Greenleaf, BC847, Richie O

Rear brake lights don't work

Postby VEfreak » Wed Dec 26, 2012 2:27 pm

I got a fix it ticket for my rear brake lights the other day. I can't figure out why they don't work. All the fuses are good and the connections seem to be fine. The brake light switch is being operated. I haven't removed it to examine it though. My truck has a trailer brake system installed but the brake lights have always worked. I've done very few electrical modifications. I installed a potentiometer to replace my failed TPS and my cargo light switch is currently not in the truck.

What tests can I run? I'm not skilled in electrical repair but I can manage if I'm told exactly what I need to do. Any help is greatly appreciated, thank you!

The truck is a 1992 W-250 if that matters.
I AM ZUES DAMNIT
User avatar
VEfreak
fuel screw!!!!
 
Posts: 185
Joined: Thu Mar 13, 2008 7:09 pm
Location: Foresthill

Re: Rear brake lights don't work

Postby dazedandconfused » Wed Dec 26, 2012 3:06 pm

This may be a stupid question but are the bulbs good? My donor truck had the brake light wiring short out blowing the element.
Big Andy
1983 Dodge D150 that has been repowered with a 93 Cummins/518 running gear AKA The Ugly Duck! I would much rather build them then buy them.[
User avatar
dazedandconfused
14mm rotor
 
Posts: 6119
Joined: Thu Apr 05, 2007 6:25 pm
Location: Walton, Kentucky

Re: Rear brake lights don't work

Postby Tacoclaw » Wed Dec 26, 2012 9:01 pm

At least its not your front brake lights. ;)

Do the hazards work both rear lights? Do the blinkers also work for each of their lights? I believe if the blinkers work that would eliminate the blinker switch as being suspect.
1990 W250 4x4
Rattles, growls, whistles, and whines.
User avatar
Tacoclaw
14mm rotor
 
Posts: 4108
Joined: Wed Mar 11, 2009 7:50 am
Location: Cheshire, OH
Top

Re: Rear brake lights don't work

Postby VEfreak » Wed Dec 26, 2012 11:07 pm

The bulbs are good and the turn signals work
I AM ZUES DAMNIT
User avatar
VEfreak
fuel screw!!!!
 
Posts: 185
Joined: Thu Mar 13, 2008 7:09 pm
Location: Foresthill
Top

Re: Rear brake lights don't work

Postby RumbleFish » Wed Dec 26, 2012 11:25 pm

brake light switch?
User avatar
RumbleFish
14mm rotor
 
Posts: 2648
Joined: Thu Jan 11, 2007 1:19 pm
Location: Indiana
Top

Re: Rear brake lights don't work

Postby VEfreak » Thu Dec 27, 2012 7:29 am

No it wasn't the brake light switch
I AM ZUES DAMNIT
User avatar
VEfreak
fuel screw!!!!
 
Posts: 185
Joined: Thu Mar 13, 2008 7:09 pm
Location: Foresthill
Top

Re: Rear brake lights don't work

Postby skilletky » Thu Dec 27, 2012 8:26 am

i had this problem my self. where the harness from the truck connects to the rear light harness was all corroded up. it looked fine from the outside, but when i pulled it apart, it was a green mess. plus the PO hacked in a 4 pin and 7 pin trailer harness.
92 d350, arp's, orings, 150lb springs, 4200 gsk ,ground pin ,64/71/14 ,ddp inj's, ats manifold, tim's tubez, ats trans, FASS, locker, timing + a tooth, bcdd intake

2001 2wd rclb dually 5sp, smarty, Bluechip FMS, TS MVP, 57/75 twins, stainless diesel pipe kit, valair clutch, airdog 150, DFI SAC 7x.014's, cheap a$$ intake, ARP studs, oringed head, CPP 115# springs
User avatar
skilletky
14mm rotor
 
Posts: 1070
Joined: Thu Jan 10, 2008 5:49 pm
Location: northern ky
Top

Re: Rear brake lights don't work

Postby Tacoclaw » Thu Dec 27, 2012 1:39 pm

My truck had green fuzzies invade the drivers side connector back behind the tea tire and cause it not to work. I'd say start there and trace them up until you find a connector that includes them both.
1990 W250 4x4
Rattles, growls, whistles, and whines.
User avatar
Tacoclaw
14mm rotor
 
Posts: 4108
Joined: Wed Mar 11, 2009 7:50 am
Location: Cheshire, OH
Top

Re: Rear brake lights don't work

Postby PToombs » Thu Dec 27, 2012 5:51 pm

It might be the multifunction switch too. (signal switch) The brake light switch feeds power thru the Mf so you get brake lights and signals at the same time. Get someone to watch, or back up to a wall, hold your foot on the brake and play with the signal switch and see if you can get it to work. Or you can check power coming and going to the switch at the connector on the column.
pete

Just enough power to break everything behind the crankshaft.
User avatar
PToombs
14mm rotor
 
Posts: 11367
Joined: Sun Jan 07, 2007 6:13 pm
Location: Syracuse NY. Snow central!
Top

Re: Rear brake lights don't work

Postby VEfreak » Fri Dec 28, 2012 7:23 am

PToombs, is that the turn signal switch you're talking about?
I AM ZUES DAMNIT
User avatar
VEfreak
fuel screw!!!!
 
Posts: 185
Joined: Thu Mar 13, 2008 7:09 pm
Location: Foresthill
Top

Re: Rear brake lights don't work

Postby dazedandconfused » Fri Dec 28, 2012 7:26 am

VEfreak wrote:PToombs, is that the turn signal switch you're talking about?


Yes it is. It controls the blinkers and hazards.
Big Andy
1983 Dodge D150 that has been repowered with a 93 Cummins/518 running gear AKA The Ugly Duck! I would much rather build them then buy them.[
User avatar
dazedandconfused
14mm rotor
 
Posts: 6119
Joined: Thu Apr 05, 2007 6:25 pm
Location: Walton, Kentucky
Top

Re: Rear brake lights don't work

Postby VEfreak » Fri Dec 28, 2012 6:51 pm

Can i short out some of the connectors in the plug into the switch to bypass it and see if it is the problem?
I AM ZUES DAMNIT
User avatar
VEfreak
fuel screw!!!!
 
Posts: 185
Joined: Thu Mar 13, 2008 7:09 pm
Location: Foresthill
Top

Re: Rear brake lights don't work

Postby VEfreak » Fri Jan 04, 2013 10:56 am

The hazard lights do not work either it seems. I removed the trailer brake kit in case that was malfunctioning and shorting it out. Should I assume it is the turn signal switch and this point because the fuses are good and I trace the wires and they all seem to be good. Unless a rat got into my frame rail and chewed the wires by the fuel tank, which were the only ones I could not see.
I AM ZUES DAMNIT
User avatar
VEfreak
fuel screw!!!!
 
Posts: 185
Joined: Thu Mar 13, 2008 7:09 pm
Location: Foresthill
Top

Re: Rear brake lights don't work

Postby Mark Nixon » Mon Jan 07, 2013 10:55 pm

Since you have both left and right turn signals, as well as the tail lights, it's NOT in the tail light harness, so abandon that approach altogether.
What you DON'T have is the key.

I say you have either a bad MFS, or a shared power feed to both is broken or corroded.
Both the hazards and brake lights share the the same power circuit, BUT the MFS switch will take out both if it fails.

A short can take out the MFS when the brakes are applied.
Shorts are funny, especially if it's water causing the short.
Water can cause a component to SLOWLY heat up, even melt plastic and never even pop the fuses.

This is especially true where rear taillight harnesses and salty water are intermingled.

If the MFS is shorted, it will be nearly impossible to verify without simply replacing it.

Mark.
Mark Nixon
 
Top

Re: Rear brake lights don't work

Postby Hegemone » Sat Apr 20, 2013 7:03 pm

You seem to be having the same problem as I've just encountered, except my headlight don't work as well. I located the problem in mine (90 w250) About two feet back from the battery on the drivers fender a large diameter black wire and red wire around 12 gauge meet a black rubber connection that feeds to 4-5 smaller wires. One of those wires was corroded, jumping this fixed both issues. My problem is there is not enough wire left to join properly. Does anyone know how the inside of the rubber connection is wired?

Hope this thread isn't too old to revive.

Image

This jazz.
Hegemone
fuel pin?
 
Posts: 13
Joined: Wed Jun 08, 2011 11:40 pm
Top

Next

Return to Electrical

Who is online

Users browsing this forum: No registered users and 3 guests

cron