swatts70 · Jun 20, 2020

Hi all.
Don't know if anyone will be able to help but I'm trying to find an internal wiring diagram for a discovery 2 rear fog light switch. Been trawling the interweb and all I've been able to find is a diagram for the front fog light switch, and knowing LR they're probably totally different internally.
About to start wiring some driving lights up via a latching really using a spare rear fog momentary switch to trigger it, in conjunction with main beam trigger.
Any info would be muchly appreciated.

discool · Jun 20, 2020

This may help you.

D2 is not my interest, but i believe its the ‘body control module’ that decides the switching, the dash switch just tells the BCM to do it.
All the info is in LRs electrical workshop manual for the D2.

sierrafery · Jun 20, 2020

swatts70 said:
About to start wiring some driving lights up via a latching really using a spare rear fog momentary switch to trigger it, in conjunction with main beam trigger.

I can tell you everything about the switch but what kind of latching relay do you want to use and how is it working, i mean what you expect from the RFL switch cos it was conceived to switch earth not live

swatts70 · Jun 21, 2020

sierrafery said:
I can tell you everything about the switch but what kind of latching relay do you want to use and how is it working, i mean what you expect from the RFL switch cos it was conceived to switch earth not live

I'm intending to use one of these relays, probably to trigger a second relay. So as long as I can find how the internals of the switch are configured I'll be able to get it working one way or another.
Thought I ask in the hope someone might have a diagram of the internal configuration rather than sit down and bell it out. I have read posts showing the front fog switches internal configuration and was doubtful that the rear switch was the same as LR never make anything simple.

Screenshot_20200620_235221_com.ebay.mobile.jpg

sierrafery · Jun 21, 2020

You can see how the internals of the switch are configured from the diagram posted by discool, it closes the circuit to earth across pins 1 and 4 when the button is pushed then the led gets feed to pin 5 from the relay.... though i doubt that a 28V relay will work on your vehicle

here are the pin disposals from the socket side

swatts70 · Jun 21, 2020

sierrafery said:
You can see how the internals of the switch are configured from the diagram posted by discool, it closes the circuit to earth across pins 1 and 4 when the button is pushed then the led gets feed to pin 5 from the relay.... though i doubt that a 28V relay will work on your vehicle

here are the pin disposals from the socket side

View attachment 212787

Many thanks for your and discool's help.
The relays coil is 12v, there were various options to choose for coil voltage, I think the picture is a generic one.

mystery · Jun 22, 2020

View attachment 212898 TRY https://www.ebay.co.uk/itm/Solid-State-Relay-Module-SSR-40DD-40A-3-32V-DC-Output-5-60V-DC-No-noise-Safe-UK/402286667237?hash=item5daa2765e5:g:KygAAOSwG0Fe2z5j FOG SWITCH.png

PLEASE NOTE THAT THE FRONT FOG LIGHTS HAVE A RELAY CONTROLLED VIA BCM FITTED IN ENGINE COMPARTMENT FUSE BOX AND THE REAR FOG LIGHTS A RELAY IN THE PASSENGERS COMPARTMENT FUSE BOX CONTROLLED VIA BCM

swatts70 · Jun 22, 2020

mystery said:
View attachment 212898 TRY https://www.ebay.co.uk/itm/Solid-State-Relay-Module-SSR-40DD-40A-3-32V-DC-Output-5-60V-DC-No-noise-Safe-UK/402286667237?hash=item5daa2765e5:g:KygAAOSwG0Fe2z5j View attachment 212893

Thanks for that Mystery.
Well on my way now.

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