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Discussion Starter #1
The other day, after getting the engine/trans etc back in I went for a ride and noticed that with the headlights off my brake lights work fine but when I hit the brakes the front fog lights also illuminate. With the headlights on the brake lights don't seem to work. Of course, hopefully unrelated, none of my dash lights work either. Any thoughts on how to remedy the headlight/brake light/fog light issue. I can't even drive the car at night safely. Thanks for the help, Skip
 

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It helps if you mention what year. Easier to check things on the schematic. Not sure if you pulled the radiator and core support out when you loaded in the engine and trans. If you did, did you connect the headlight grounds?
Problem almost sounds like the body ground is missing. Do you have the ground wire from battery (-) to the right inside fender?
 

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Sound like your dash lights are related. I had a similar problem on my chevelle. Turned out I pulled some grounds that I didn't replace. I put them back on and added a few more... fixed the problem plus a few other problems too.
 

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Discussion Starter #4
What a dummy....She is a '70 454 SS car....sorry about that. I did remove the radiator. If it was a ground wouldn't that just keep the lights from working. This is almost like wires are crossed or something. Rear brake lights and front fog lights coming on with pedal application as long as the headlights are off. When the headlights are on rear brake lights don't work. I am not positive but I think this was not a problem before the motor removal. However, I might be mistaken and just didn't notice the condition earlier. I didn't have the car long before I pulled the trans/motor etc. Sorry about the brain fart in not listing the year or engine. Thanks, Skip
 

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I sorta doubt the wires are crossed. That would take a little effort to do that. Shiney new engines = sometimes bad grounds.
First thing is to try and see why the headlights act strange. Question again: Do you have the body ground strap from the battery negative post (-) to the right inside fender? Shown as a 12 gage wire.
 

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Discussion Starter #6
No seperate bonding strap. As best I can tell there are really only 2 specific grounds. One is the negative lead from the battery to the alternator bracket and the second is just a wire from the block to an igntion component at the back of the engine(I am not at home and don't recall what it specifically goes to but I think it is the resistor). There was no ground/bonding strap on the car when I got it. Maybe that is the ticket. Where should it be? Thanks!
 

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From the battery negative post (-) to the right inside fender. Get that tied in first and we can move on.
 

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Discussion Starter #8
Thanks John. Do you per chance have a picture showing how the strap attaches to the post and what attachment on the inner fender? I am going to look at some of the featured cars and see if I can see it there. I won't be back home until Sat. am and will give it a shot. Skip
 

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The strap doesn't attach to the post itself. It is part of the negative cable. You will need to buy a new negative cable with a pigtail lead coming off of it.
 

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Discussion Starter #10
I tried a ground from the pig tail off the neg. battery cable and noticed no difference. I did find out however that my brake and turn signals do work with my headlights on but they come on very dim. I also noticed that my turn signals seem to blink really fast but are really dim. Any thoughts on what is causing this? Thanks, Skip
 

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OK, you now know that the body has a good ground or made sure that it was grounded. Next pull one of the rear bulbs out and measure the yellow or green wire to ground with a meter. As someone steps on the brakes, you should have 12 volts to ground. Find a clean spot on the body to measure from.
If you have 12 volts, take a piece of test wire. Touch one end to the bulb base right where it meets the glass. Touch the other end of the wire to that clean spot on the frame you found. Have someone step on the brakes. Does that make the bulb come on brighter? If it does poor socket ground.
 
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