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> '74 fog light relay, how does it work without grd?
benalishhero
post Sep 29 2009, 01:25 PM
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I'm at the end of some rewiring in my '74 2.0. What I can't figure out is how the fog relay is supposed to work without a ground. I have studied the diagram and as far as I can tell the relay isn't grounded.

Can anyone give me a clue?

I need another set of eyes and brain for this one.

Thx.

Thomas
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SirAndy
post Sep 29 2009, 02:46 PM
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QUOTE(benalishhero @ Sep 29 2009, 11:25 AM) *

Can anyone give me a clue?

It's grounded through the foglight switch.

On the foglight relay, 86 goes to the foglight switch (gray-brown wire) where it is ground when the switch is pulled.

87a is not used on that relay, on other relays 87a and 86 are normally bridged.
(IMG:style_emoticons/default/bye1.gif) Andy
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benalishhero
post Sep 29 2009, 03:09 PM
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QUOTE(SirAndy @ Sep 29 2009, 04:46 PM) *

QUOTE(benalishhero @ Sep 29 2009, 11:25 AM) *

Can anyone give me a clue?

It's grounded through the foglight switch.

On the foglight relay, 86 goes to the foglight switch (gray-brown wire) where it is ground when the switch is pulled.

87a is not used on that relay, on other relays 87a and 86 are normally bridged.
(IMG:style_emoticons/default/bye1.gif) Andy



Thx for the reply. I tried that with no luck. I'm thinking I may have a bad switch.

Andy, is that terminal 31 on the switch that illuminates the switch light?

That's how I originally had it wired.
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SirAndy
post Sep 29 2009, 03:50 PM
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QUOTE(benalishhero @ Sep 29 2009, 01:09 PM) *

Thx for the reply. I tried that with no luck. I'm thinking I may have a bad switch.
Andy, is that terminal 31 on the switch that illuminates the switch light?
That's how I originally had it wired.


31 (brown ground wire) goes to 31 on the emergency flasher switch.
15 (black/blue wire) goes to 56 on the light switch.
K (gray/brown wire) goes to 86 on the fog light relay.

(IMG:style_emoticons/default/bye1.gif) Andy

http://www.pelicanparts.com/914/parts/Elec...lectric_73A.jpg

http://www.pelicanparts.com/914/parts/Elec...lectric_73B.jpg

PS: You should be able to test the switch with a volt meter ...
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benalishhero
post Sep 29 2009, 04:09 PM
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Ya, I just tested the switch- it's fine.........

Thanks for your help!
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904svo
post Sep 29 2009, 05:09 PM
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Look at the wiring diagram real close, it gets it ground from the left side low beam.
That's why the fog lights only work with the high beam on! When the low beams or on it puts 12 volts toward the relay when they are off it now a low resistance ground.
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SirAndy
post Sep 29 2009, 05:58 PM
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QUOTE(904svo @ Sep 29 2009, 03:09 PM) *

That's why the fog lights only work with the high beam on!

You mean the other way round. They only work with the low beams on!

If you turn on your high-beams, the fog-lights go out ...
(IMG:style_emoticons/default/shades.gif) Andy
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904svo
post Sep 29 2009, 09:22 PM
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QUOTE(SirAndy @ Sep 29 2009, 03:58 PM) *

QUOTE(904svo @ Sep 29 2009, 03:09 PM) *

That's why the fog lights only work with the high beam on!

You mean the other way round. They only work with the low beams on!

If you turn on your high-beams, the fog-lights go out ...
(IMG:style_emoticons/default/shades.gif) Andy



You right! Sorry
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benalishhero
post Sep 30 2009, 07:30 AM
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Still can't get them to work. My diagram contradicts.

This is how I have it set up.

First off, I don't have a gry/br wire.


from relay

86->wht/bl to fuse 1
87->wht/yw to foglights
85->gy/rd to K
30->rd/bk to fuse 10

from fog switch

15->bk/bl to 56(lite switch)
31->br to 31 (flasher switch)

I'm quite confused at this point.
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904svo
post Sep 30 2009, 09:39 AM
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QUOTE(benalishhero @ Sep 30 2009, 05:30 AM) *

Still can't get them to work. My diagram contradicts.

This is how I have it set up.

First off, I don't have a gry/br wire.


from relay

86->wht/bl to fuse 1
87->wht/yw to fog lights
85->gy/rd to K
30->rd/bk to fuse 10

from fog switch

15->bk/bl to 56(lite switch)
31->br to 31 (flasher switch)

I'm quite confused at this point.


Here how it works, with lights on, power is supply to terminal #15 on fog switch
with fog light switch operated power flows from K terminal (gray/red) to #86 (fog light relay coil winding) the other side of the winding (#85) white/blue goes to fuse
#1 (high beam) which supply LOW RESISTANCE GROUND to operated the relay.
If fuse is dirty or High beam burn out the fog lamps will not light. Word of caution here some halogen lamp do not provide low resistance ground at times!!
With the fog lamp relay operated power is supply to terminal #30 (red/black) from
fuse #10. Current now flows thru terminal #87 (white/yellow) to the fog lamps
the other side of the fog lamps are grounded thru the brown wire. The brown wire
on the switch (31) is the ground for the lamp in the switch.

Hope this helps you.
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benalishhero
post Oct 3 2009, 06:24 PM
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Solved. I had the headlight ground on the wrong connector at the sealed unit which back fed power to the dimmer relay- Duh.

Thx for the help guys.
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