Putting fog lamp switch in a truck without them (2005 2500HD)

[AuroraGirl]

Hi, I recently in november had to fix some mouse damage under my fuse box and thats why Im making this post, i was wondering what the fog lamp switch does if you install it without putting a fuse or relay in, and you simply just swap the cargo lamp switch out for a dual fog/cargo switch. My truck was never installed with fogs, but i have the harness on both sides and fuse box terminals for the relay and fuse.
When i put the switch in, it turns on my parking lamps. Is this to be expected or is that an indication of a problem?

I just pressed it to see what it does, and the park lamps turn on and backlighting on the dash. the backlight on the fog switch also lights up. does the cluster have a fog indicator or just the switch?

 

[99Sierra2500]

All I notice is that there is an indicator light next to the button, and the fog lights light up. The light next to the button is very small, it's enough you can see it in daylight, but that is about it.

 

[AuroraGirl]

All I notice is that there is an indicator light next to the button, and the fog lights light up. The light next to the button is very small, it's enough you can see it in daylight, but that is about it.

But no parking lamps (front and rear side markers, rear tails)

 

[99Sierra2500]

But no parking lamps (front and rear side markers, rear tails)

The drl driving/headlights are on, because it is a 99.

 

[stutaeng]

I thought your BCM had to be reprogrammed to get your foglights to work with factory switch, no.

 

[AuroraGirl]

I thought your BCM had to be reprogrammed to get your foglights to work with factory switch, no.

99-02 yes

 

[99Sierra2500]

I bought $20 lights off amazon iirc.

 

[AuroraGirl]

All 2003-2007 trucks are preconfigured to use foglamps BESIDES early 2003 models as stated in the blue note