Fog light

[Surf01]

In order to comply with UK regulations, a fog light was fitted on my Surf. i never used it until very recently and when I switched it on, it blew all the rear lights. I checked for a short but could not find out. The switch itself has four terminals but only three are connected up, these are 2, 3 & 4. It is too late to take the vehicle back to the dealer as I bought it a year ago and from a dealer near Guildford, but how the fog light got through a MOT at the time is a mystery. Can any one advise?

[Dog_Book]

Well, i checked my wiring for same thing. I found that the rear fog was drawing power directly from the back lighting circuit. So i sorted it with a relay taking power from the battery

[POPEYE]

Mine was the same only they ran the wire under the truck and connected it
to the side light curcuit, Ive added a couple of small 3 1/2" fogs on the front
so i had to run em through a relay and added the rear fog to it, Ian

[M35A2]

Mine is a mystery. When it's on it works fine, as do all the other lights. But when I put my high beam on, the fog light goes out. I think it must be wired up to the main headlight dip circuit. But I'm buggered if I'm going to try and find the cause.

If it aint broke and all that!!

[Morr]

Mine is a mystery. When it's on it works fine, as do all the other lights. But when I put my high beam on, the fog light goes out. I think it must be wired up to the main headlight dip circuit. But I'm buggered if I'm going to try and find the cause.

If it aint broke and all that!!

Fog lights front & rear (particularly front) are often wired this way, I think its actually the correct method, and its the one I always use. If you use high beam in foggy conditions the light is reflected back at you by the moisture droplets in the air, which decreases your vision, this is why you should always use dipped beams in fog or falling snow. So if the weather conditions permit you to safely use your main beams, then fog lights should not be required.

[Medieval Dave]

In order to comply with UK regulations, a fog light was fitted on my Surf. i never used it until very recently and when I switched it on, it blew all the rear lights. I checked for a short but could not find out. The switch itself has four terminals but only three are connected up, these are 2, 3 & 4. It is too late to take the vehicle back to the dealer as I bought it a year ago and from a dealer near Guildford, but how the fog light got through a MOT at the time is a mystery. Can any one advise?

It's not a big load (normaly 25w max) so it shouldn't take out the lighting fuse. Mine was wired the same and no probs. My guess is that the wire is routed badly and has chaffed through the insulation where it goes inside the vehicle, or has been squashed where it is routed under carpet etc. the usual route goes right past the read seat hinges on the drivers side for example.

If you used a tester and couln't find the fault then it could be it is intermittently shorting. I reccomend the following.

1. borrow a multimeter (also known as a DVM) if not a normal tester with a lamp is ok but not as good.
2. note which wires connect where on your switch, then disconnect them
3. you have three wires.
one is from the battery. you will find 12V on this. (red probe on the wire, black probe on bare chassis metal) if you like you can cut this wire somewhere and fit an inline 12V fuse in a little holder, this way you wont blow all your lights again, but remember it might be in an awkward location to change.
The second goes to the light. if the bulb is in and everything is in order i guess that should be about 6ohms (horseshoe symbol on the meter) if its near enough zero then you have a short.
The third wire is for the Neon on the switch. depending on the arraingement that may be another 12V feed, or an earth (directly connected to the chassis) if it is an earth then it could be your problem, cos if the switch has the wires on wrong then when you turn it on you connect your 12V to your earth via the switch. Leave that earth wire (if it is) disconnected, and if the fog then works (without the neon lamp on the switch) but the fuse goes when you put the thing back, then that'll be your issue.

let me know if I can help, and also if I am being to complicated or two simple if you know what I mean.


Dave.

p.s. if you don't get me through the forum try tdbanks (at) btinternet.com

[Surf01]

Thanks Dave. What you are saying makes sense I will need to buy some more mini 10 amp fuses. annoys me buying them from Halfords aas you have to buy several other misc fuses whihc you will never use. Anyway will perserver.

[BUSHWHACKER]

I get mine from here........

http://www.screwfix.com/app/sfd/sea/...pi=1&cn=1&cd=1


Cheaper to buy in bulk.

[Gizmo]

This may be too simple but I found that when I moved the Fog light onto the bumper from hanging below the wiring had been connected incorrectly inside the holder [I didnt pay attention and just moved wire for wire to the connectors] switched it on and it was then I realised that the wires were connected incorrectly

Never had to use the Fog Light so never knew until I tested it.

[Medieval Dave]

Thanks Dave. What you are saying makes sense I will need to buy some more mini 10 amp fuses. annoys me buying them from Halfords aas you have to buy several other misc fuses whihc you will never use. Anyway will perserver.

Get 'em here then

http://www.vehicle-wiring-products.c...page/home.html

[M35A2]

Fog lights front & rear (particularly front) are often wired this way, I think its actually the correct method, and its the one I always use. If you use high beam in foggy conditions the light is reflected back at you by the moisture droplets in the air, which decreases your vision, this is why you should always use dipped beams in fog or falling snow. So if the weather conditions permit you to safely use your main beams, then fog lights should not be required.

My front PIAA fogs come on on side lights and stay on regardless of the high beam. It's just the rears that go out when the high beam is applied.