Fog light cr@p

gtirneil

gtirneil

New Member
Someone tell me whats wrong with this please.

MOT time is this week and all i think my car will fail on is the fog light, as it doesnt work.

This is what i have:

Dash mounted push button switch with LED, 3 wires coming out the back.

All wires hooked up, switch head lights on and led on fog switch comes on, but fog light doesnt.

Ive followed one of the wires out the back of the switch all the way to the rear cluster (inner brake light used as fog). Said wire is then attatched to 2 ( :? ) wires going into the fog bulb, but the fukcer refuses to light up, ive changed the bulb twice and it doesnt work.

Could this be related to my sidelights not working and my heater lights not working, is there a fuse anywhere i might have missed, i checked the ones under the coin tray (1 random 1 was blown), ive also checked the ones next to the battery.

Any ideas people, ive spent 2 days searching before anyone mentions doing a search.
 
B

buffalobilla

New Member
go to a garage that doesnt care about the fog light. my R has been through 2 MOTs and doesnt have a fog light :lol: :lol: :lol:
 
D

DarrenJLewis

Guest
Hi,

Just wondering if it ever worked wired up the way it is, do you know exactly which wires go where from the switch?

If you've got a mapin near you they sell cheap volt meters, which might be worth getting think they are just under 5 pounds, usually you'll find a big pile of them somewhere in the store. Then you can find out exactly what voltage you've got where.

Usually a single pole single throw toggle switch with led which it sounds like you might have (just 3 pins coming out of the back led inside is made up like this)

Pin - 1 - simple switch - 2 - Led and resistor here - 3
Put positive here (1) Feed to bulb (2) Negative here (3)

So when the switch is open there is no connection between pins one and two so no current to your bulb and no current the the led (the light in the switch). When you close the switch pins 1 and 2 are connected so the bulb gets connected to your 12v supply and your led is turned on too.

It might be possible you're sending the bulb the voltage across the led/resistor which won't be enough to light it (I've done it once myself).

If you get a volt meter you can check you've got 12 volts coming into the switch and then check what you get at the fog light bulb etc.

Hope this makes sense.
Cheers,
Darren.
 
gtirneil

gtirneil

New Member
i used a volt meter on it, i tested the lights 1st when they were on and got 1.3 (set the volt meter wrong i think :oops: ) then i did the fog light, when it was switched on and also got 1.3, i have no idea whats up, i cant have put 2 dodgy bulbs in can i???

Im just going to take it tomorow and hope he passes it :roll:
 
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DarrenJLewis

Guest
Hi,

Sounds like you've got the volt meter set up wrong, with the car not running you should be seeing somewhere near 12v on it. The volt meter should have a place to put the negative, put the black wire here, it should say something like neg or ground.

Then typically you should have two places to put the red wire, one is for volts/ohms and should have something to that effect written near it, this it the one you want. The other is for current you don't need that one right now.

So stick the red wire in the volts/ohms place on the meter and the black wire in the negative place. Then select the range you want, you need to find the section on the dial on the front that has a v (volts) and various settings like 0.2, 2, 20, 200 etc. There will probably be two like this, one with a ~ symbol next to it you want the other one the ~ symbol means AC. So select a number bigger than but closest to 12 (should be 20).

Then stick the black wire of the negative terminal of the battery and the red wire on the positive and you should see around 12 on the display.

Good luck with the MOT! :)
 
Fast Guy

Fast Guy

Moderators
Staff member
gtirneil said:
Could this be related to my sidelights not working and my heater lights not working, is there a fuse anywhere i might have missed, i checked the ones under the coin tray (1 random 1 was blown), ive also checked the ones next to the battery.
Click to expand...
It may be, if they've wired it into the sideilght circuit. Get your sidelights working (it'll be a fuse) and see if your foglight works.

You'll fail on the sidelights as well
 
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