Rear Fog Lamp

[Guest petelee]

Hi

 

I've just completed the main wiring of my 2B/4, based on Sierra loom, but with XR3i stalks. Everything works perfectly, but I have recently read that the rear fog lamp must only work when headlights are on. As mine is wired the same as the Sierra, the fog lamp can also be operated when the sidelights are on. Apparently this would be an IVA failure!

 

I have tried to re-wire my rear fog lamp through the headlight circuits, but I can only get it work EITHER with main beam on OR with dip beam, but not with both, as the main and dip are on separate circuits. If I try to join the rear fog lamp to both circuits, then the headlights don't work correctly!

 

Do I need to connect the rear fog lamp to a separate relay or something, so it will work when either circuit is active? Although I've sorted all my own wiring, I'm not very experienced with relays!

 

The only other thing I can think of, is to have two separately wired bulbs in my fog lamp?

 

Can anybody help?

 

Pete

[Guest Tweedy]

I'm not sure but I think that rear fog lights should only work when on dipped beam.This is on the basis that if you can use main beam its not very foggy.Also you must have a warning light on the dash to show when the rear fog is on.

Cheers Mike

[Guest peter2b2002]

yep thats correct , only to work with dip beam, problem solved :good:

peter2b

[Guest petelee]

yep thats correct , only to work with dip beam, problem solved :good:

peter2b

 

 

Oh, brilliant! That's easily sorted now, then!

 

Thanks guys!!!!!!!!!!!!!

 

Pete

[Guest petelee]

Oh, brilliant! That's easily sorted now, then!

 

Thanks guys!!!!!!!!!!!!!

 

Pete

 

 

Oh No!

 

I've just checked the draft IVA Manual, and it says:-

 

"4. The rear fog lamp(s) must only illuminate when dipped beam, main beam, or front fog lamps are lit"

 

....unless it's been changed since the draft?

 

Pete

[Longboarder]

That's the way it is in the final IVA manual. So they can only light if main or dip is on (assuming you don't have any front fog lamps!).

 

What column stalks are you using and what loom?

 

Nigel

[Guest petelee]

That's the way it is in the final IVA manual. So they can only light if main or dip is on (assuming you don't have any front fog lamps!).

 

What column stalks are you using and what loom?

 

Nigel

 

 

Hi Nigel

 

I'm using Sierra loom, but Escort Mk4 XR3i stalks. It took me a while to get the stalks to work correctly in all aspects (ie main, dip, flash & dim/dip), but did finally manage it - it was all down to the earth cables causing me headaches, as the Sierra's headlight switch is split into two stalks, and the XR3i headlight switch is all on one.

 

I tried all sorts of combinations to get the fog lamp to work on both main & dip but not sidelight, but just can't seem to sort it. Thought that maybe two bulbs in one fog lamp might be the answer!

 

Pete

[Longboarder]

If using the later sierra stalks you could add a relay which is earthed through your illuminated fog light switch to connection 56 on either of the stalks. Constant fused supply to terminals 86 and 30 on the relay. 85 connected to your fog light switch and then to 56. 87 on the relay connected to the fog light itself and you could tee off this to a dash telltale if your switch hasn't got one.

This is just one option using a relay. Pic below.

 

Nigel

[Guest petelee]

If using the later sierra stalks you could add a relay which is earthed through your illuminated fog light switch to connection 56 on either of the stalks. Constant fused supply to terminals 86 and 30 on the relay. 85 connected to your fog light switch and then to 56. 87 on the relay connected to the fog light itself and you could tee off this to a dash telltale if your switch hasn't got one.

This is just one option using a relay. Pic below.

 

Nigel

 

 

Thanks again Nigel.

 

I'll try and adapt that to work from the XR3i stalk. I'm a bit of a novice regarding relays, but I'll certainly give it a go!

 

Does it matter what sort of relay I use? I've got a couple of tall ones (probably from the Sierra's electric windows or something), and I've also got some smaller ones from the XR3i fuse-box.

 

I won't get a chance to try it until the weekend, but I'll let you know how I get on!

 

Pete

[megadodo]

The rear fog light wont pull enough current to need a relay but it wont do any harm and it may make your fog light switch contacts last a bit longer.

[Guest petelee]

Hi

 

I managed to get an hour in the garage to try and sort the fog lamp problem...

 

I followed Nigel's circuit with a relay, but I just get the same results! No matter which cables I join into, I can still only get the fog lamp to work with one or the other - dip or main - it's like I need an extra cable going to the relay - so that one cable comes from the dip circuit, and one from the main circuit - but they mustn't join together, or the headlights don't work correctly!

 

Pete

[Longboarder]

The critical point on the sierra stalks is there is a 'headlight' switching on circuit and separate circuits to switch between dip and main. In the case of the sierra switch it is the earthing of the 56 wire through the switch in the right hand stalk which is a constant, regardless of wether you are on dip or main. If the XR stalks have switching on on one stalk and dip/main on the other then you should be able to rig something similar. But I haven't got a wiring diagram to work on.

 

If there's someone who does diodes looking I'm sure it would be simple enough to take supplies from both main and dip circuits to a relay using diodes to keep them independent but allowing either to supply the switching current and adding a fog light switch to earth to control it.

 

Nigel

[miikae]

As Nigel has just mentioned a pair of diodes (IN4001)is the simplest option cheap too as about 20p each from Maplins, one in each leg (main & dip) and both joined together feeding the Fog light relay coil ,

 

Mike

[Longboarder]

So that's like so. Bear in mind I don't know which way round you draw the diodes in the diagram or which way round you fit the little darlings in real life neither but they're like lectric valves, flow one way only.

 

Nigel

[fry61]

Last circuit diagram needs another S/P switch before dip/main switch otherwise either dip or head would be on permanantly, & with the addition of a master headlamp switch (controlling feed to both head & dip relays) your back to your first circuit; the switch connection numbers I leave to your greater knowledge.