Front Brake Lights Working ???

[G-749]

Yeah , went to shop working on my 70 C 20 Longhorn after they called , front turn signal lights work in conjunction with normal rear brake lights when brake pedal pressed . Bought someone else project . 70 C 20 Longhorn, factory dual battery setup, underdash GM a/c , bed lamp , original TAX stamped 350 4 bbl motor , pwr front disc brakes bunch more , SPID MISSING, bought a tilt steering column they installed for 700R4 tranny, engine harness not hacked but don't have 2nd battery installed, turn signals n lights work. Am I missing something ? Anyone ever hear of this? Or have had this issue? Can't work on it myself , rotator cuff thing , looking for solution before shop starts looking for "wiring issues "@hourly rate . WTF , never heard of this but I saw it myself . Maybe someone with more knowledge than me can enlighten me about this. Good luck on all your projects. Thanks

[Richard]

First question do front turn signals work? Second question do front running/parking lights work? If one does not work it is connected to brake circuit instead of the one intended. The bulb in that location has two elements and serves two purposes. Two circuits.

[kwmech]

Originally Posted by G-749

Yeah , went to the shop working on my 70 C 20 Longhorn after they called , front turn signal lights work in conjunction with normal rear brake lights when brake pedal pressed, bought a tilt steering column they installed for 700R4 tranny, engine harness not hacked, turn signals n lights work. Am I missing something? Can't work on it myself. Good luck on all your projects. Thanks

So I edited all the stuff out that does not pertain to the issue and am still trying to figure what the problem is. Do the lights only work when the brake pedal is pushed?

[Rust_never_sleeps]

I'm wondering if someone tried to rig up the side markers to be blinkers and screwed the pooch. Maybe they grounded to the brake circuit

[G-749]

Went there , got the key , headlights and side marker lights work normal, brake pressure makes both front and rear brake lights work, no turn signals at all , took out wrecked column being used for 700R4 tranny, bought new column for 700R4, GM column from forum member also horn doesn't work anymore and parking brake warning light doesn't work anymore . Lot of stuff not working correctly after column swap, . Not pointing fingers at anyone , but what worked ain't working no more, when checking lights n turn signals and brake lights, didn't look in the front for brake lights, looked in rear mirror for rear brake lights n turn signals. Don't want to pay shop @ hourly rate to look for electrical problems that happened after steering column swap. I'm all ears as to what anyone else thinks guess, knowledge of this problem, back up lights have never worked,. Thanks , Good luck on all your projects

[Steeveedee]

Get yourself a wiring diagram. I've seen vehicles back in the '70s where, when one stepped on the brake pedal, the front marker lights came on. This is usually because people put the stop/turn wiring on the front wiring. Not 100% on that, so best bet is, again, get the wiring diagram. You can find them here-

https://67-72chevytrucks.com/vboard/...ghlight=hatzie

[PbFut]

With as many items not working, I would verify which side of the firewall is messed up. Maybe remove the light and engine harness at the firewall connector and test each pin. That should give you an idea which harness to give attention to. I tend to suspect the harness in the column given your comment on it being newly swapped. Though it seems extreme, bad grounding can do some really funky things. Especially in the brake and turn signal circuit.

[kwmech]

Sounds like either the turn signal switch is bad or one or 2 of the wires is crossed going up the column. Does the switch return like it should when you go around a corner or do you have to manually return it to center? Plug in the old column and see what happens and/or compare the 2 column plugs

[G-749]

Duuuh , I feel like a huge dumb a$$ , went back to the shop working on " Little Red" Longhorn, got the owner and the key went out to look things over , pulled steering wheel to look inside , still doing the "front brake light thing" , both of us checking g all the lights, still no turn signals ,, I said try the 4 way flasher , he pulled it and said " it's really hard to pull" , pulled it all the way out , 4ways started flashing , pushed it in and tried the turn signals , they worked , try the brakes, only rear brake lights worked, what a trip !! Word up to all , if you ever have the problems with turn signals not working, CHECK to make sure the 4 way flasher is all the way in or out, mine was just part way, just enough that the flashers wouldn't flash, but just enough so the turn signals wouldn't work , and the front lights would work when the brake light switch was activated. I wouldn't have believed this possible if I was not there to see it for myself. Sure glad the shop owner was there to see this before they started looking for wiring problems @ shop labor rate !!! Thanks to all who replied.
Good luck on all your projects. Hope this info helps some one else !!!
And yes the back up lights started working also , can't say enough good things about the new steering column ,awesome job ,
Operator error on the 4 way flasher switch , my bad !!!

[70STOVEBOLT]

Glad you got it figured out, and thank you for posting the solution.

[Rust_never_sleeps]

Nothing like a binary system with nonbinary behavior :-D

[Orange Crate]

I you are planning on keeping the truck and with all of the other electrical issues why not buy a new harness headlight to taillight and be done with it?