Please forgive me if this topic has been covered before - I did a advance search on Fog Light Switch & noth'en came up + I "think" this is gonna be a head scratcher. My baby is a 2003 C5 / Convertible / almost 93k on it & I've had it about a year & half. Not sure if I created this issue or not - given this Vet is 19 - going on 20 years old - who knows - reason I say is - took the center console out to install a after market radio - which was a challenge onto itself - thus - I still have the center console out - with all the wireless wrapped in plastic to be extra cautious of shorts etc / the fog light / trunk release switch has been replaced with a brand new one from SMC out of Michigan - all the fuses supposedly related to both the fog lights & trunk release - yet - the switch isn't working - not sure what relay controls this circuit.

Issue started about two weeks ago - first the trunk release stopped working - the fog lights kept working & then the fog lights stopped working this week.

Here's the really odd kicker - when I use the key fob to release the trunk - it works.

I have my Approach Lights On set in my options - thus - when it's dark/dusk & I use my fob to unlock the car - ALL the lights come on - less the headlights of course - the fogs work + the led on the fog light switch lights up.

Thus - I'm totally confused - if the switch has power going to it & the led lights up + all the fuses are good & the fogs light up with the Approach / Unlock working & the trunk pops via the fob .... not sure were to go from here ...

Any suggestions / idea's - would REALLY be appreciated ...

Thank you in advance.

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I would start with the under hood fuse box and check the relay for the fog light switch but if the fog lights are working when you unlock the car it seems that electrically everything is fine so that is strange.
At this point, I'd double check that new fog light switch and the appropriate electrical connections with a test light and go from there.

One of my favorite sayings is, just because it's new doesn't mean it's good.

 

Hey Autotragic,

Thank you for your reply.

I double checked the fuse under the hood & reset the replay - sadly - noth'en.

Today - went to Autozone - dropped $25 for a new relay - still nuth'en.

Tested the Approach Option - fog lights came on - led on the switch came on - but as soon as I opened the drivers door & cut the circuit - lights naturally went off.

Twisted the stock to light up the side markers etc - pushed the switch & nuth'en - no led - no fogs ...

@ this point - I "think" I'm going to disco the battery & check every stink'en fuse in both boxes - nothing to lose @ this point & it'll be cheaper then try to have a shop figure it out.

Of course - if anybody else out there has a magic bullet to try - I'm MORE then happy to entertain the option ...

& sigh - also ordered a Chilton Manual cause I find a clear diagram on-line of the wiring on that circuit + I can't seem to find a large / clear on-line diagram of the grounding points which maybe related to this issue as well.

I know there are 20 grounding points - love to know were they are - thus - I'm hopeful the Chilton manual gets into that level of detail

Thank you Autotragic for your time - muchly appreciated.

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- Fix'd it today

In my case & I don't know if this will apply in all cases but here are the bit's & pieces which were replaced:
Keep in mind - this was to solve both the Fog Light issue & the Trunk Release issue - thus ...
a) Inside foot well fuse / replay panel - replaced Fuses 26 & 32
b) Removed / Rest Relay - 39
c) Inside Engine Compartment fuse / relay panel - replaced Fuses 1 & 6 - replaced relay 39 / Removed / Reset Relay 37
d) Replaced duel mode (Fog / Trunk ) panel switch (in my case - it was from SMC out of Michigan)

Not sure why - why out of the blue this happened - but - the Vet is almost 20 yrs old & I drive it when I can - which is often - def NOT a garage queen - thus - guess stuff wears out after 20 years 'eh ...

SIgh - FEELS SO much better having a fully functional sweet ride ...

Thank you all - enjoy ...

 

I echo your sentiment, little things not working but the crap out of me! In your case I'd guess the interior relay or a bad connection at the switch. The approach light function bypasses both of those and works for you, so that's all that's left.

 

Like IHBD said above the 96 is timed by the ccm. I was thinking there would be a good chance backing plates would be inside the door but with my luck if I dont have them they wont be there. Plus i need to see whats going on with the missing hatch release button. My goal at this point is to get these doors put together correctly without glueing stuff in lol.