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-   -   Signal lamps help again (https://67-72chevytrucks.com/vboard/showthread.php?t=733103)

randy500 03-26-2017 10:03 AM

Re: Signal lamps help again
 
I think you have 2 problems.
Problem 1:
Week lamp at green wire and strong on 4way at firewall is from contacts in turn signal switch.
Disassemble the switch, clean and lube it.


Problem 2:
1. Bad ground at right rear taillight housing or no power to the housing.
Test: Use test light with a known good ground to pins in the housing then post the results.
If power to pins test the bulb in the other side. and
With bulb installed, use a wire from known ground to brass on side of bulb, if this corrects the problem then the housing is not grounded, if it doesn't correct it then the pins in the housing are not contacting the bulb. The springs behind the pins are bad.

Test problem 2 and correct first. You should get at least strong 4 way flash when this is corrected but possibly not signal and stop because of weak signal at firewall.

randy500 03-26-2017 10:04 AM

Re: Signal lamps help again
 
I assume you r test results were from you testing the rear light plug which is above the gas pedal, right?

randy500 03-26-2017 10:13 AM

Re: Signal lamps help again
 
Here is a description of the rear turn signal light paths

Turn signal
It flashes on either side because power originates from the turn signal flasher and power is connected to either side through the turn signal switch and onto the left or right lamp, the flash comes from the flasher, a load is created which generates heat inside the flasher, the bi-metal contact heats up, bends and the light goes out, the metal cools and the light goes on. Same thing happens on the other side except a different contact is used in the turn signal switch.
4 way
This is a separate power path through the 4 way flasher and connects directly to the tail light lamp wires on other side of turn signal switch (bypasses the contacts for turn signals) so they 4 way on both sides no mater signal switch position.
Stop lamps
bypass turn signal switch for rear lamps. Front will flash while brakes applied but rear will not.

Maybe that helps to understand the system.

66clow 03-26-2017 10:19 AM

Re: Signal lamps help again
 
Quote:

Originally Posted by randy500 (Post 7896811)
I assume you r test results were from you testing the rear light plug which is above the gas pedal, right?

Correct. I am showing power at the RR tail lamp when I use my test light. But I'll do the checks.
Got a feeling my problem may be the signal switch since that is really the only thing that was twisted around a bit when I pulled the steering column. Ugh! Thanks

randy500 03-26-2017 10:24 AM

Re: Signal lamps help again
 
Quote:

Originally Posted by 66clow (Post 7896771)
Here is where I am. Checking at the firewall wire going to rear. I have power at the Brown wire. Yellow wire have constant power and blinks with signal on. Dark green the power on constant and signals but is weak lamp with signal on but bright with hazard on. With light switch on both dk green and yellow bright, no power on Brown wire. If that is how it works?

LR lamp blinks and stop light. Nothing on right. Light switch on no difference at fire wall yellow green Brown all have power. Unsure if that is how it works.

I wonder if your describing this correctly.
Here is what you should have.

Lights off
No power to any thing at rear
Turn signal switched to left, should give power to yellow and then flash.
Turn signal switched to right, should give power to green and then flash.
Push on brake pedal and yellow and green should have power, if a signal switch is on that one will flash

Lights on
Everything the same as above except power to the brown wire. Which gives tail lamps, side marker lamps and license lamp power.

66clow 03-26-2017 11:18 AM

Re: Signal lamps help again
 
Quote:

Originally Posted by randy500 (Post 7896835)
I wonder if your describing this correctly.
Here is what you should have.

Lights off
No power to any thing at rear
Turn signal switched to left, should give power to yellow and then flash.
Turn signal switched to right, should give power to green and then flash.
Push on brake pedal and yellow and green should have power, if a signal switch is on that one will flash

Lights on
Everything the same as above except power to the brown wire. Which gives tail lamps, side marker lamps and license lamp power.

I need to go verify but have power to brown when light switch off and no power with it on which I guess should be switched? But now I'm confused lol. I'll do some checking again and confirm what I have.

randy500 03-26-2017 11:26 AM

Re: Signal lamps help again
 
Quote:

Originally Posted by 66clow (Post 7896906)
I need to go verify but have power to brown when light switch off and no power with it on which I guess should be switched? But now I'm confused lol. I'll do some checking again and confirm what I have.

The brown wire also lights up the front lights so you shouldn't have power to it with the headlight switch off.
The brown wire does not go through the turn signal switch and gets power from the headlight switch.

66clow 03-26-2017 11:47 AM

Re: Signal lamps help again
 
Quote:

Originally Posted by randy500 (Post 7896913)
The brown wire also lights up the front lights so you shouldn't have power to it with the headlight switch off.
The brown wire does not go through the turn signal switch and gets power from the headlight switch.

Ok so could be the headlights switch or some where along the brown wire.

randy500 03-26-2017 12:09 PM

Re: Signal lamps help again
 
Are you saying brown has power when switxh is off?

66clow 03-26-2017 12:10 PM

Re: Signal lamps help again
 
Quote:

Originally Posted by randy500 (Post 7896954)
Are you saying brown has power when switxh is off?


Yes, but I'll go out this afternoon to confirm

randy500 03-26-2017 12:22 PM

Re: Signal lamps help again
 
Ok, let me know when you confirm, if brown has power then all running lights have power with switcb off

66clow 03-26-2017 02:50 PM

Re: Signal lamps help again
 
Here are my est results. But read the bottom below what discovered.

Left brake tail lamp works. Test grounded taillamps but no change. No changes with wires at firewall with brake pedal. Just Brown wire power.

http://i1262.photobucket.com/albums/...ps4jqmh9kk.jpg

I plugged in the plug at the firewall and used test lamp and green, brown and yellow wires show power but connector unplugged test no power. This with nothing on. Tested with signals, yellow flashes and green goes off. Rt flasher, green goes off yellow solid. Must be a wiring issue going back from fire wall underneath ? Going to look.

randy500 03-26-2017 03:28 PM

Re: Signal lamps help again
 
You must have a bad 1157 bulb feeding faint power into the brown wire, the bad bulb must be in one of the front parking lights, remove front bulbs and place to the side, put the ones from the rear in the front and test firewall plug again.

randy500 03-26-2017 03:29 PM

Re: Signal lamps help again
 
And when you did the test at the firewall you have the harness to the rear disconnected right?
If you didn't have it disconnected then do the test again to isolate the brown power wire to just the front lights.

randy500 03-26-2017 03:39 PM

Re: Signal lamps help again
 
Can you confirm this....
Key off headlights off
Is there power to the brown wire at the firewall for the tail lamp cable?
If yes are the front marker lights lit up?
Is there power at the front lamps? If so then they are not grounded and are getting a ground from something else.

66clow 03-26-2017 04:01 PM

Re: Signal lamps help again
 
[QUOTE=randy500;7897157]Can you confirm this....
Key off headlights off
Is there power to the brown wire at the firewall for the tail lamp cable?
If yes are the front marker lights lit up?
Is there power at the front lamps? If so then they are not grounded and are getting a ground from something else.

Randy Randy Randy. Thank you thank you, you helped me narrow down my problem. I'm discovering the joys and pains of living on the beach. Apparently the salt water air corroded my half fanny wiring repair. The center harness that I didn't want to spend the money on. Was fine 3 months ago living in LA but not Florida. :fry:
Well ill patch this one till my new one comes in. Thanks again! And thank you everyone else that chimed in.

http://i1262.photobucket.com/albums/...psffs0wxbj.jpg

http://i1262.photobucket.com/albums/...ps1lr4mmag.jpg

randy500 03-26-2017 04:05 PM

Re: Signal lamps help again
 
That does look ugly

66clow 03-26-2017 04:06 PM

Re: Signal lamps help again
 
I have no idea how this related to pulling a steering column but guess I was just driving with no lights for some time!


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