2020-B1-8

Author Topic: Defroster light switch now stays lit all of the time  (Read 638 times)

j79z28

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Defroster light switch now stays lit all of the time
« on: November 12, 2020, 10:22:46 AM »
I recently hooked up the ground wire to my relay for the defroster on my 1977 TA. Now I see the green light is always lit. I know there was a bulletin back in 77 about defroster switch changes. It mentioned swapping the pink and black wires. Problem is I don't know if that has been done in the last 43 years.  Any ideas where to begin? Anyone come across this?

firebirdparts

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Re: Defroster light switch now stays lit all of the time
« Reply #1 on: November 12, 2020, 09:42:27 PM »
Do you want to see that bulletin?
I want to be like Paul Kenny when I grow up
Joe Bays
1977 Y82 4-speed (red interior)
1978 Skybird 350
1978 Redbird 305
1979 Redbird 301 4-speed
1992 Lincoln Mark VII LSC/SE (red)
1970 Datsun Pickup
1953 Chevy pickup (converted 4x4)
1988 T-bird Turbo Coupe


j79z28

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Re: Defroster light switch now stays lit all of the time
« Reply #3 on: November 13, 2020, 09:40:51 AM »
Thanks for the replies. I read the bulletin, and my car was built after the new switch was brought into production. I have pulled the switch out, and verified it is the new style. I would like to verify the connector wires to the switch are in the correct location. On the back of the bulletin I was told it says that if the green light stays on when plugged in, swap the black and pink wires. Maybe someone in the last 43 years replaced the switch and swapped the wires around when they should not have. Firebirdparts, do you have a pigtail in stock you can send me a picture of or reference to help me?
« Last Edit: November 13, 2020, 09:43:34 AM by j79z28 »

firebirdparts

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Re: Defroster light switch now stays lit all of the time
« Reply #4 on: November 13, 2020, 10:04:57 AM »
I do have wiring harnesses galore, and they tend to be the later style.  The light is held on by that relay, so it may be that relay is not working right. 

Looking at the diagram, black is always grounded, and the light is wired straight off the rear window power.  so it would be interesting to know if the rear window is actually on all the time.
I want to be like Paul Kenny when I grow up
Joe Bays
1977 Y82 4-speed (red interior)
1978 Skybird 350
1978 Redbird 305
1979 Redbird 301 4-speed
1992 Lincoln Mark VII LSC/SE (red)
1970 Datsun Pickup
1953 Chevy pickup (converted 4x4)
1988 T-bird Turbo Coupe

j79z28

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Re: Defroster light switch now stays lit all of the time
« Reply #5 on: November 13, 2020, 12:25:04 PM »
So the timer for the defroster to turn itself off  is in the relay, and  not the switch? The green light came on as soon as I plugged the ground to the relay back in. I did not turn on the defroster. That's why I was thinking a crossed wire at the pigtail to the switch. On the back of the bulletin it mentions if green light comes on, wires may be crossed. In what location on pigtail is the black and pink wires supposed to be correctly located. I am thinking someone in the past read the bulletin incorrectly and switched wires (black and pink) when he shouldn't have.  Thank you for any help.

firebirdparts

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Re: Defroster light switch now stays lit all of the time
« Reply #6 on: November 13, 2020, 02:20:50 PM »
Okay, let me look.
I want to be like Paul Kenny when I grow up
Joe Bays
1977 Y82 4-speed (red interior)
1978 Skybird 350
1978 Redbird 305
1979 Redbird 301 4-speed
1992 Lincoln Mark VII LSC/SE (red)
1970 Datsun Pickup
1953 Chevy pickup (converted 4x4)
1988 T-bird Turbo Coupe

j79z28

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Re: Defroster light switch now stays lit all of the time
« Reply #7 on: November 13, 2020, 04:18:22 PM »
Man that would be great. Looking forward to what you find. Thank You!

glhx

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Re: Defroster light switch now stays lit all of the time
« Reply #8 on: November 16, 2020, 11:50:34 PM »
Also look at my thread on defroster. I have detailed pictures of the switch taken apart. The switch was sacrificed.

Basically.....the little thin wire in the switch is light positive. The only ground on the switch is the black negative.

The other two wires run the defroster.

Power from the relay powers the defroster......and the light. I have a diagram of that as well that shows this in detail
« Last Edit: November 16, 2020, 11:52:16 PM by glhx »

j79z28

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Re: Defroster light switch now stays lit all of the time
« Reply #9 on: November 18, 2020, 08:02:38 AM »
Thanks GLHX. I saw your thread, it is excellent. I am waiting to hear from firebirds parts as well. Hopefully he can let me know the correct location of the pink and black wires on the connector that goes to defrost switch.

firebirdparts

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Re: Defroster light switch now stays lit all of the time
« Reply #10 on: November 20, 2020, 07:57:14 AM »
So here are some samples:
I am pretty sure this is a 1979 and is what you are looking for.

I think this is a 1977 and seems to be the same, so maybe post bulletin

This is a 1980 or 81, after they switched to purple for the circuit actually going to the window.  That circuit is green on your car.  It has to be doubled up somewhere, but they moved that point around.  When that circuit is hot, it powers both the window and the light.

I'm surprised somebody cut that.   I guess that's a good place to get ground and power, but who would know that? Somebody knew his Trans Ams.

I pulled up the 1980 wiring diagram at sticked in this forum and we're all in agreement.  I did look at a 1974, incidentally, and they didn't have this wiring as far as I can tell.  It was an add-on back then.
« Last Edit: November 20, 2020, 08:01:46 AM by firebirdparts »
I want to be like Paul Kenny when I grow up
Joe Bays
1977 Y82 4-speed (red interior)
1978 Skybird 350
1978 Redbird 305
1979 Redbird 301 4-speed
1992 Lincoln Mark VII LSC/SE (red)
1970 Datsun Pickup
1953 Chevy pickup (converted 4x4)
1988 T-bird Turbo Coupe

j79z28

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Re: Defroster light switch now stays lit all of the time
« Reply #11 on: November 24, 2020, 03:51:44 PM »
Firebird parts you are the man! Thank you for the pics. I will check them against what I have and let you know.

j79z28

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Re: Defroster light switch now stays lit all of the time
« Reply #12 on: November 29, 2020, 12:27:08 PM »
Ok, my wires in the connector match what pictures are. So we can confirm my wiring at the connector is correct. I think my relay may be the issue as to why the green light stays on the defroster switch constantly. Firebirdparts, do you have any good relays I can purchase? The part number on the back of my relay is 527361. Thanks again for everyone's  help!

firebirdparts

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Re: Defroster light switch now stays lit all of the time
« Reply #13 on: December 04, 2020, 10:28:18 AM »
I've got several.  I guess I could test them, too.  Let me rig up something.
I want to be like Paul Kenny when I grow up
Joe Bays
1977 Y82 4-speed (red interior)
1978 Skybird 350
1978 Redbird 305
1979 Redbird 301 4-speed
1992 Lincoln Mark VII LSC/SE (red)
1970 Datsun Pickup
1953 Chevy pickup (converted 4x4)
1988 T-bird Turbo Coupe

j79z28

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Re: Defroster light switch now stays lit all of the time
« Reply #14 on: December 27, 2020, 07:19:09 PM »
sounds good. Let me know what you come up with. Thank you for the help. Hope to hear from you soon.

Re: Defroster light switch now stays lit all of the time
« Reply #14 on: December 27, 2020, 07:19:09 PM »


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firebirdparts

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Re: Defroster light switch now stays lit all of the time
« Reply #15 on: January 07, 2021, 10:06:33 AM »
Sorry for the delay.  I haven't forgot.  I have time to rig up a tester. 
I want to be like Paul Kenny when I grow up
Joe Bays
1977 Y82 4-speed (red interior)
1978 Skybird 350
1978 Redbird 305
1979 Redbird 301 4-speed
1992 Lincoln Mark VII LSC/SE (red)
1970 Datsun Pickup
1953 Chevy pickup (converted 4x4)
1988 T-bird Turbo Coupe

j79z28

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Re: Defroster light switch now stays lit all of the time
« Reply #16 on: January 07, 2021, 09:18:32 PM »
no problem. Let me know what you come up with. Thank you.

firebirdparts

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Re: Defroster light switch now stays lit all of the time
« Reply #17 on: January 13, 2021, 08:51:52 PM »
I rigged up a headlight that I can control with these relays.  Probably a little much on the wattage.  So I am going to test a couple.  Is yours a 4 prong?
I want to be like Paul Kenny when I grow up
Joe Bays
1977 Y82 4-speed (red interior)
1978 Skybird 350
1978 Redbird 305
1979 Redbird 301 4-speed
1992 Lincoln Mark VII LSC/SE (red)
1970 Datsun Pickup
1953 Chevy pickup (converted 4x4)
1988 T-bird Turbo Coupe

j79z28

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Re: Defroster light switch now stays lit all of the time
« Reply #18 on: January 13, 2021, 09:12:06 PM »
I will check tomorrow when I get off of work. Thank you for the help.

firebirdparts

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Re: Defroster light switch now stays lit all of the time
« Reply #19 on: January 14, 2021, 11:16:56 AM »
So far every one I've tested worked just fine.  They kicked off in about 10 minutes.

I'll send you a PM.
I want to be like Paul Kenny when I grow up
Joe Bays
1977 Y82 4-speed (red interior)
1978 Skybird 350
1978 Redbird 305
1979 Redbird 301 4-speed
1992 Lincoln Mark VII LSC/SE (red)
1970 Datsun Pickup
1953 Chevy pickup (converted 4x4)
1988 T-bird Turbo Coupe

j79z28

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Re: Defroster light switch now stays lit all of the time
« Reply #20 on: January 14, 2021, 09:03:43 PM »
Just sent you a pm. Thank you.

Re: Defroster light switch now stays lit all of the time
« Reply #20 on: January 14, 2021, 09:03:43 PM »
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