78 nyb brake lights stay on


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Oct 16, 2020
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We have a low mileage 78 NYB and just took it out of garage storage.
The brake lights stay on all the time.
We first thought sticking pedal or bad switch , but unplugging the switch , the brake lights stay on
Any suggestions? Signals and lights work as they should.
Does anybody have a lighting diagram for a 78 NYB. Probably a short but a diagram would help.

Are you sure you unplugged the switch? I assume that car has cruise control and there will be 2 sets of connections to the switch. One set for the brake lights and one set for the cruise.

Fuse 7 supplies power to the purple wire. When the connection is made in the switch, power flows through the white wire through the steering column, to the hazard switch and relay and then out back. We know you have power. Seems to me the switch is stuck closed.

The blue lines and pigtail on the brake switch are for cruise and unplugging them is useless to the test.

I have had several instances of the brake switch sticking. Spray some electrical contact cleaner up in there and flick/ twist the switch/ assembly has done the trick for me.
Thanks for the fast responses.
yes I unplugged both the pink and white wires and brakes lights still stay on. Could it be in the column or something pinched in the floor?
The NYB just turned 20k miles. Was my Uncle Jon's car new in Hawaii and he gave it to me 88.

Okay, from the FSM, power should flow from fuse 7 though the pink wire to the brake switch, out the brke switch via the white wire, into the column through the white wire to the hazard light switch then through the turn signal switch then out the column through the dark green wire to the harness to the back of the car.

So pulling the pink or white wires from the brake switch should deprive the lights of power...so that's confusing.

Pull the fuse (number 7) and report back. Lights should go out.
The brake lights run through the turn signal switch. Burnt connections at the hazard in the original turn signal switch in my 1972 Fury caused all kinds of taillight problems. I replaced the turn signal switch with one that I had bench tested that was from another vehicle. All the problems went away. It's a matter of checking a lot of continuities across the turn signal switch. The install is fairly simple.
Your turn signal connector may look like this under the steering column. You could try disconnecting it and making sure the lights go out. Then you'll of isolated the problem to either the turn signal switch or wiring from the brake light to the turn signal switch or from the turn signal switch to the connector.

Thanks all for your responses. Let me pull fuse 7. Then check wiring to the hazards/ signal switch.
I'm working till 2 as a volunteer, but will crawl under the dash when I get home.
Thanks for all the knowledge.
I pulled fuse 7 and brake lights are still on! I'll pulled the steering wheel next and check the signal/ flasher switch.
I unplugged the flat signal/ flasher connector and the brake lights turned off. Thanks for the tip "70furyconv" and others. It's looks like the same switch as a 70's E body and also Aspen/ Volare! Did Mopar use the same switch across the line of cars from 70 (key in column ) up until they put the high beam selector in the signal stalk?
I'll report back when column surgery is completed!
If you have non-tilt tele, then, yes the turn signal switch is plentiful and was used across many lines (Cordoba etc). If you have tilt-tele, it is a unique C body only item as no other car lines had tilt & tele columns.
If you have non-tilt tele, then, yes the turn signal switch is plentiful and was used across many lines (Cordoba etc). If you have tilt-tele, it is a unique C body only item as no other car lines had tilt & tele columns.
'70 up used that switch.
The saga continues.
I've got a replacement switch.
With key off the pink and white brake switch unplugged, and the signal switch unplugged at the bottom of the column, the left brake light remains on. At least the weather is pleasant and cooperating!
Another update..

Pulling fuse 7 brakes go out, with pink and white wires disconnected.

Putting fuse 7 back in, left brake light lights up.... then plugging in the signal harness the other rt brake lights up. I believe that part to be correct.where harness lights both brake lights.
My guess? is power from the fuse 7 is powering up the white wire!
Found the short.
Somewhat intermittent. From the fuse box to the brake switch the wires were pinch together. White had power all the time keeping the light on. Not sure why before that the lights stayed on before with fused pulled, but changed the signal flasher switch anyway.
All the best to the knowledge of this group.