no rear lights

[78C10 sleeper]

Tryed a flasher didn't help I just put a turn signal switch in it could it be installed wrong I mean it was pretty strait foward

[Irish_Alley]

ok let me understand the lights (im guessing running) work with the headlight on but if the headlight are off they wont work? and the rear lights turn on when you turn the headlights on? what about 4 ways?. i had a problem with the pig tail on my switch on the steering column it had to be just right for it to work but i was also using a 80s steering column on a 74 wire harness

[rich weyand]

Yeah, you need to give us a little chart of what works when and what doesn't. Something like this example:

Headlights on
- tail lights are on
- turn signals work
- flashers don't flash
- brakes light up brake lights and front signals

Headlights off
- tail lights are off
- turn signals don't work
- flashers flash
- brakes light up rear lights only (i.e. correct)

Gives us something like that and I betcha we can figure it out.

[78C10 sleeper]

Ok new flasher didn't fix it think I may pull the steering wheel tomorrow check out the components under there what do u guys think?

[bd]

Ok new flasher didn't fix it think I may pull the steering wheel tomorrow check out the components under there what do u guys think?

This..........

Yeah, you need to give us a little chart of what works when and what doesn't. Something like this example:

Headlights on
- tail lights are on
- turn signals work
- flashers don't flash
- brakes light up brake lights and front signals

Headlights off
- tail lights are off
- turn signals don't work
- flashers flash
- brakes light up rear lights only (i.e. correct)

Gives us something like that and I betcha we can figure it out.

[Irish_Alley]

complete that check list by rich and see where you are

[78C10 sleeper]

Ok did the check list so with the head lights OFF I only have brake lights.with the head lights ON I have brake lights and power to all lights except the back up lights because I havent wire them up to my shifter.but either way the signals wont blink. The four ways work in the cab but not at the rear of the truck my front signals have power but they don't blink.     

On a side note my high/low beam switch is Geting hot could that be the cause
thanks alot guys for all ur help

[Irish_Alley]

what about running lights? its the first click on the headlight switch

[78C10 sleeper]

Yes they the running lights work

[bd]

Ok did the check list so with the head lights OFF I only have brake lights.with the head lights ON I have brake lights and power to all lights except the back up lights because I havent wire them up to my shifter.but either way the signals wont blink. The four ways work in the cab but not at the rear of the truck my front signals have power but they don't blink.

On a side note my high/low beam switch is Geting hot could that be the cause
thanks alot guys for all ur help

• If the headlamp dimmer properly switches between high and low beam, check for poor (corroded or loose) connections at the dimmer switch.  The dimmer switch will not impact the rear lights.
  
  
• Did you replace one or both flashers?  Upper (hazard) or lower (turn)?
  
  
• Switch the ignition ON and turn signals ON (either direction), then use a test light to check for power at the yellow and dark green wires entering/exiting the turn signal switch connector under the dash at the right side of the steering column.  With the turn signals ON you should see power at the yellow (on left turn) and dark green (on right turn) wires.  If not, then check for power on the purple wire at the same turn switch connector - it should be 12 volts whenever the ignition is ON, regardless of the turn switch position.  Post up what you find.

[78C10 sleeper]

Ok I will check that tomorrow and I didn't relize there where to flashers I only replaced the one on the fuse box where is the other one located?

[bd]

Both flashers plug into the fuse box.  The turn flasher is located at the bottom right corner, the hazard flasher is located at the top left corner.

[rich weyand]

Note two flashers in this pic: http://www.rowand.net/Shop/Tech/images/GMATOStyleFuseBlock-Front2.jpg

The wiring diagram shows the two flasher locations on the fuse block: http://www.73-87chevytrucks.com/techinfo/wiring_diagrams/77-80_instrument_pg2.jpg

[78C10 sleeper]

My fuse box looks totally different it is the old style with glass fuses but I only see one flasher in the top left hand corner but in the bottom left hand corner there looks like there is a place where one could possibly go....thanks

[78C10 sleeper]

Ok so I checked the wires going up the column the yellow, dark green,and purple have no power the only wires that do is a brown one and a black one