72 Chevelle SS Dash Swap_No hazards/brake lights, turn signals work - Chevelle Tech
Electrical & Wiring Troubleshooting electrical problems.

 
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post #1 of 15 (permalink) Old Jul 11th, 20, 10:29 AM Thread Starter
 
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72 Chevelle SS Dash Swap_No hazards/brake lights, turn signals work

Hi all and thanks for taking the time to read this.

Just finished an SS dash swap and here are the things that are now not working. It all worked when the sweep dash was in the car.

1. Hazards and brake lights inoperable, they worked fine before with the old dash, all fuses good, all turn signals blink inside and out
2. No power to radio harness or heater control lamp

Any recommendations on where to start looking would be fantastic to get this resolved, thanks!
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post #2 of 15 (permalink) Old Jul 11th, 20, 10:35 AM Thread Starter
 
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Re: 72 Chevelle SS Dash Swap_No hazards/brake lights, turn signals wor

Forgot to mention that the headlights and rear tail running lights do work
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post #3 of 15 (permalink) Old Jul 11th, 20, 11:09 AM
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Re: 72 Chevelle SS Dash Swap_No hazards/brake lights, turn signals wor

The turn signals, hazards and brake lights use the same circuitry basically.
1. Is the hazard flasher in place? I believe is mounted away from the turn signal flasher.
2. Is the connector/s on the brake light switch connected to he switch and is it adjusted correctly?
3. There should be voltage on one side of the brake light switch and not the other. If there is no voltage on either side of the switch, you need to look at the fuse block.
4. Check the fuse for the stop/turn signals again. I feel this is your most likely problem. I know you said all the fuses are good, but stick a probe on both sides of the fuse and check for voltage. It may look good visually, but it could be bad.
5. The radio circuitry, do the same as above. This is one of those that needs the ignition/ACC "on" to check.
6. Heater control bulb, do the other bulbs light up on the dash and radio? A pinched wire will blow the fuse. This is a single wire circuit. either the voltage is there or its not. Start tracing back to the fuse block.

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post #4 of 15 (permalink) Old Jul 11th, 20, 1:06 PM Thread Starter
 
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Re: 72 Chevelle SS Dash Swap_No hazards/brake lights, turn signals wor

Thanks for the replies!

1. Is the hazard flasher in place? I believe is mounted away from the turn signal flasher. - (Yes)
2. Is the connector/s on the brake light switch connected to he switch and is it adjusted correctly? (Yes, it worked before the dash swap and did not mess with the brake switch)
3. There should be voltage on one side of the brake light switch and not the other. If there is no voltage on either side of the switch, you need to look at the fuse block. (There is no voltage at the switch)
4. Check the fuse for the stop/turn signals again. I feel this is your most likely problem. I know you said all the fuses are good, but stick a probe on both sides of the fuse and check for voltage. It may look good visually, but it could be bad. (There is no voltage at the fuse with a multimeter)
5. The radio circuitry, do the same as above. This is one of those that needs the ignition/ACC "on" to check.
6. Heater control bulb, do the other bulbs light up on the dash and radio? A pinched wire will blow the fuse. This is a single wire circuit. either the voltage is there or its not. Start tracing back to the fuse block. (Yes, the other dash lights on instrument panel light up, there is no voltage on this bulb connection)
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post #5 of 15 (permalink) Old Jul 11th, 20, 1:46 PM
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Re: 72 Chevelle SS Dash Swap_No hazards/brake lights, turn signals wor

Of course it wouldn't have anything to do with any circuit other than the brake light/rear hazard light circuit but there are two normally closed set of contacts in the turn signal switch that send power to the rear brake light filaments.
They are the yellow and green wires in the column connector that are fed by the white wire from the brake light switch.

But if the rear turn signals work and the white wire is hot when you push on the brake, then you can forget about those

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post #6 of 15 (permalink) Old Jul 11th, 20, 2:04 PM Thread Starter
 
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Re: 72 Chevelle SS Dash Swap_No hazards/brake lights, turn signals wor

I separated the fuse block again to have a look and see no obvious issues, no bent pins and all looks good and clean
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post #7 of 15 (permalink) Old Jul 11th, 20, 2:46 PM
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Check the comb connector on the side of the fuse block. It may not be fully seated. It does the hazards.....

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post #8 of 15 (permalink) Old Jul 11th, 20, 4:22 PM
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Re: 72 Chevelle SS Dash Swap_No hazards/brake lights, turn signals wor

Quote:
Originally Posted by Kyle McCabe View Post
Thanks for the replies!

1. Is the hazard flasher in place? I believe is mounted away from the turn signal flasher. - (Yes) THE HAZARD FLASHER IS MOUNTED ON THE FUSE BLOCK. The turn signal flasher is mounted seperately.

3. There should be voltage on one side of the brake light switch and not the other. If there is no voltage on either side of the switch, you need to look at the fuse block. (There is no voltage at the switch) THERE SHOULD BE VOLTAGE AT THE ORANGE WIRE OF THE SWITCH. WHEN YOU PRESS THE BRAKE PEDAL YOU SHOULD HAVE POWER AT THE WHITE WIRE. YOU SHOULD THEN SEE POWER AT THE COMB SWITCH OR TURN SIGNAL SWITCH CONNECTOR AT THE COLUMN AS PER DEAN AND LEVOON'S POSTED.
4. Check the fuse for the stop/turn signals again. I feel this is your most likely problem. I know you said all the fuses are good, but stick a probe on both sides of the fuse and check for voltage. It may look good visually, but it could be bad. (There is no voltage at the fuse with a multimeter) HERE'S YOUR ISSUE. SHOULD BE HOT AT ALL TIMES. Might be a bad connection on the back side of your fuse box.
Look for power at the fuse. It should be hot at all times key on or off. If no power there, check the backside of the fuse box. The fuse blades are not getting power from the red wire. You should see power at the red wire as the other items it drives seem to be working for lack of complaint. Orange wire off the fuse leads to the 4 way flasher then splices off to supply power to the brake light switch. When the braqke light switch is activated, the power runs through the white wire to the turn signal switch.
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post #9 of 15 (permalink) Old Jul 11th, 20, 4:40 PM
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Re: 72 Chevelle SS Dash Swap_No hazards/brake lights, turn signals wor

You said no power to hazard fuse. Correct? The red wire is connected to the fuse box bussbar. The bussbar is connected to the fuse clamps or blades through a rivet. You're not seeing power at the fuse as there is a poor connection at this point. Through the bussbar through the round rivet to the fuse blades.
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post #10 of 15 (permalink) Old Jul 12th, 20, 11:50 AM Thread Starter
 
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Re: 72 Chevelle SS Dash Swap_No hazards/brake lights, turn signals wor

Guys, the comments are so appreciated! Here is the latest update: I took the entire fuse block apart again and cleaned it all but it was already extremely clean and put it all back together and did nothing any differently. Now here is the kicker, the hazards, brake light, and radio all now work but guess what does not now that previously did?? THE TURN SIGNALS
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post #11 of 15 (permalink) Old Jul 12th, 20, 2:46 PM
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Re: 72 Chevelle SS Dash Swap_No hazards/brake lights, turn signals wor

Quote:
Originally Posted by Kyle McCabe View Post
Guys, the comments are so appreciated! Here is the latest update: I took the entire fuse block apart again and cleaned it all but it was already extremely clean and put it all back together and did nothing any differently. Now here is the kicker, the hazards, brake light, and radio all now work but guess what does not now that previously did?? THE TURN SIGNALS
Do you have power aT BOTH SIDES OF THE DIR SIG fuse... Test it on the blades, not the fuse. If so, check for power at the flasher pink wire. Dir flasher is on top of the steering column support. Not on fuse box flasher which is your hazard flasher. If there is power there, switch out the emerg flasher and the dir sig flasher and see if it works.
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post #12 of 15 (permalink) Old Jul 14th, 20, 8:48 AM Thread Starter
 
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Re: 72 Chevelle SS Dash Swap_No hazards/brake lights, turn signals wor

Come to find out the GAUGE fuse visually looked good but was bad and everything seems to be working now. Not sure why because the turn signals should have nothing to do with this circuit.

The only issue now is that all the instrument lights do not appear to be coming on which is strange because for the ones that do, they ALL share the positive and negative circuit imprints as I have traced them on the diagram of the board.
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post #13 of 15 (permalink) Old Jul 14th, 20, 9:52 AM
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Instrument lamps are fed off of a second fuse (3 amp) in the fuse panel through the dimmer switch. Make sure the dimmer is turned all the way clockwise with the lights on.

Levon Hovagimian
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post #14 of 15 (permalink) Old Jul 14th, 20, 10:42 AM
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Re: 72 Chevelle SS Dash Swap_No hazards/brake lights, turn signals wor

This is a used dash? Make sure that the bulbs and sockets are clean. My lamp sockets looked good and fairly shiny, but had no continuity with a known good bulb inserted.

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post #15 of 15 (permalink) Old Jul 14th, 20, 3:39 PM
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Re: 72 Chevelle SS Dash Swap_No hazards/brake lights, turn signals wor

Also there is the special ground wire strap to dash light socket. I had to go back and add it when I reinstalled my dash.

Example:

https://www.ss396.com/mm5/merchant.m...&xscreen=prodb

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