weidman

Any C-3 wiring gurus out there? Recently had the motor pulled to rebuild short block on my'71 LT-1 and now the turn indicator lamps light with brake pedal application! They dont blink...they just light up along with brake lights (they work ok). Any suggestions. I think something got reconnected wrong with motor re-insatll. I don t even know where to start looking. Thanks for any help..

thiatt

All my info is on a 77 vett. Looking at a electrical trouble shooting manual. The purple wire going to the directional signal/hazard switch assem. feeds the turns the white feeds the stops, the brown feeds the hazards check to see if the wire connector is plug in properly. the light blue goes to the left turn indicator, dark blue goes to right turn indicator. the yellow goes to the left turn\stop light the dark green goes to right stop\turn light in rear. check that all these connections are plugged into the corrisponding locations. check any connections from start to end to see if anything got flipped or mis matched. hope this helps.

SteveG75

Bad ground.

The brake lights are grounding through the turn signal circuit. This happens because the brake light filaments also act as turn signals. Check all the grounds front and rear. There should be one back by the brake lights and one on the radiator support.

More info would also be helpful. Which turn lights? Front I assume. Another thing on these cars is that the front turn signals can have 12v on both sides of the bulb (which means no light) when the the turn signal is on parking lights are on.

I had a ground issue where if I hit the horn, the front turn signals illuminated (bad ground).

weidman

Clarification. The green turn signal indicators (arrows)in speedo and tach ...come on with tail lights...Press on the brake pedal...they both (right and left) and brake lights come on together???

Avette4me

The usual suspect for wierd acting stuff like the OP has.

TimAT

And that one, as a suspect, gets convicted 99% of the time,

thatcorvetteguy

SteveG75

Bad ground. Since the brake filaments are also the turn signal filaments, the brake lights are not properly grounded at the rear and electrons are flowing in weird ways.

Mashman

I had that exact problem, and it was simply a bad flasher module.

addballer696

I had this problem a couple of times and i found out that first of all my hazards don't work and that when the button is actually pushed in, into the on position, my turn signals light up when braking. simple solution for me was to just turn the hazards off.

weidman

To all thanks for your input. Most people are saying "bad ground" but where? I went through assembly manual and crawled in and and around but couldnt locate gound at rear or by tail lights. Any chance you can be more specific in location description or even a pic? Also, I did see today that is the front turn signal lamps themselves that come on with brake lights and turn signal indicators lights in dash all at the same time. Any "specific" things I can try?Thanks again

TimAT

The tail end grounds to the frame, usually on the left rear or on the rear crossmember. The front grounds to the core support that is grounded to the frame. Look for a single wire that runs off by itself. At the rear, you have green, yellow, brown, (lights), and a tan (fuel sender), light green, (backup lights) and a black (ground)

mj9311

i had a similar problem on my 76 and it ended up being the volt regulator inside the alternator

weidman

Dont know if this helps but the ammeter gauge needle moves when you step on brake pedal or turn on lights.....with NO KEY in ignition!!
Any other thoughts...this seems to be getting more confusing. Again thanks to all yours suggestions....

...Roger...

That's normal.
I agree with the others that you most likely have a lack of ground problem. If you can get about 10' of wire attach 1 end to the neg term of battery and touch the other end to one of the taillight bulbs outer case. This will give you a temporary ground to the rear lights.
edit- like in the pic

SteveG75

Normal. Ammeter is always hot.

Look under the rear bumper at the wiring harness. Look for a wire that is bolted to frame (probably on the driver's side above the muffler) or a loose ring terminal.

Hammerhead Fred

For the rear ground simply check under the rear where the wiring harness plugs into the bulb assemblies. You SHOULD find a black wire bolted to one of the bulb retaining bolts on the rear of each socket. This wire runs over to each socket then finally to the drivers side where it connects directly to the frame at the drivers rear corner of the frame. Shouldn't miss it. You'll also find a ground from the fuel gauge that connects to the same harness and then onto the center/rear frame brace. You can test for poor ground by simply running a long wire from the negative side of the battery and connecting it directly to the harness ground terminals/bolts described above. Once connected test your brake lights and see if the problem goes away. If so then you've isolated your problem and need only check your ground points for the faulty/broken/dirty connection.

...Roger...

Whether you find the factory ground where it bolts to frame or where it bolts to the back of each socket or you just touch the brass outer case of the bulb itself you should be able to tell very quickly if "lack" of ground is your problem.

One very GOOD thing about ground circuits is that GROUND is usually very accessible. In most circuits that have bulbs ever bulb is an easy access to the ground in that circuit.
In the front of the car , grounding 1 bulb (like the pic above)will ground the entire front lighting system including the headlights.
In the rear it is the same ,one bulb "outer brass case" grounds everything including in most cases the alarm system,rear courtesy lights,fuel gauge,side markers and license plate light.
Same thing in the dash area , one bulb case will ground everything.

I have several 15' rolls of wire with alligator clips that saves me huge time isolating ground problems. I can run temporary grounds to both front and rear lighting circuits in minutes. If that cures the problem then all I have to do is find the poor ground connection.

Moral to the story is , use the grounds don't be afraid of them.

Edit- Here is a pic of my well used very valuable time savers.
IMO these $3 , 5 minutes of time ,jumpers are an invaluable tool for the Corvette owner.
Getting down off my soapbox now !

Bremquest

few years late just had same issue. Bad flasher

loup68

Please see my recent post, 68: no brake lights. There my be a possibility that it is the turn signal switch. Maybe Willcox can help you out. Lou.