No Power To Fog Light Switch (2017 Thunderbird Lt)

XerxesDGreat · Jun 17, 2025

As the title says. I've been sporadically trying to hunt down why my fog lights aren't coming on, but so far, no dice. Today, I verified the following:

no power at bulbs

relay (in the front fork area) is good; no power is getting to it

no power at the switch

fuse is good

I'm sure the next step is probably "look at all the wiring", but that's kinda tough given how much of it goes through the body. I figured I'd ask here, see if anyone else has had this issue.

Thanks!

joe mc donald · Jun 18, 2025

XerxesDGreat said: ↑

As the title says. I've been sporadically trying to hunt down why my fog lights aren't coming on, but so far, no dice. Today, I verified the following:

no power at bulbs

relay (in the front fork area) is good; no power is getting to it

no power at the switch

fuse is good

I'm sure the next step is probably "look at all the wiring", but that's kinda tough given how much of it goes through the body. I figured I'd ask here, see if anyone else has had this issue.

Thanks!
Click to expand...

@XerxesDGreat Welcome to the family. Do check those fuses properly as a good looking fuse can be a beggar. I made a small light i use from fuse to a battery just to be sure. Failing that you may have a broken wire and sorry it testing them. Also make sure the earths are good and the switch its self. Keep us all in the know as you go. Also like a picture if you get time to tap the upload a file button bottom right corner.

MICK LEONARD · Jun 26, 2025

XerxesDGreat said: ↑

As the title says. I've been sporadically trying to hunt down why my fog lights aren't coming on, but so far, no dice. Today, I verified the following:

no power at bulbs

relay (in the front fork area) is good; no power is getting to it

no power at the switch

fuse is good

I'm sure the next step is probably "look at all the wiring", but that's kinda tough given how much of it goes through the body. I figured I'd ask here, see if anyone else has had this issue.

Thanks!
Click to expand...

I have an America and checking for the upcomming MOT (thats a mandatory mechanical inspection for all you non brits) I noticed the rear brake light didn't come on when I pulled the front brake (front and rear brakes operate the rear brake light). Then the horn didnt work either. So, one thing at a time. Check the front brake switch, and it was knackered, so get a new one (£6 on Amazon, £17 + £9 postage from Triumph supplier). Fit it and all worked, plus now horn also worked. So on looking at the wiring diagram the horn and light switches are on the same circuit. So its worth checking, as one duff switch may cause other issues.