Fog light conversion-improved wiring

Just done Pete Betts fog lamp conversion on my sup. to pete who did most of the hard work

If you want to keep your bulb failure warning in place/have an illuminated fog light switch, the attached works. You need 4 x 10w wire wound resistors, available at maplin, part no H15R at £0.19 each. My wiring is blue in the diagram.

nice work, im just about to do the PB fog wiring on mine, bonus

sorry to be slow, but isn't it best to have the fog in one of the brake lights or no? is that what the diagrams on here are for and can someone let me know what bits i need to buy from Maplin?

Thanks!!!

You've got 3 options for the foglight:

Hangy downy thing - NOOOO!!!!

Red bulb in the offside reverse light - OKish

Or Pete Betts conversion - converts the inside brake lights to a fogs when switched on, but stays as stop/tail when the fogs are off.

You need 2 x five pin automotive relays and some wire and terminals to do the basic conversion. Add 4 x resistors as above if you want the bulb fail circuit to still work. If you're in Birmingham, let me know and i can give you a hand if you need.

thanks v much! my dad could prolly sort the wiring but im completely useless with this stuff - think you need an 'electrical mind' i reckon. the SVA company in Southampton wired a caravan fog and cut/glued it on near my number plate - wanna get rid of it!

nice job!

I am in the process of having my supe imported and I just know that I'm going to have the danglies (and not the dogs), so I'm going to get this sorted before anything else because the day I get it the dangly is coming off.

couple of questions...

I'm a dumb ass so...

where did you put the components?

I assume that NC in the diagram is not connected? (told you I was a dumb ass )

And this will really show my electrical ignorance, but why do you have 4 resistors in parallel?

All the components are behind the trim panel in the boot.

n/c is not connected

In order to convince the bulb failure unit, the resistors need to draw roughly as much current a 2 x 21w stop bulbs. as the resistors only have a max rating of 10w you need 4 of them. Using 4 x 15ohm resistors you use approx 36w, which is enough to fool the bulb failure unit that there are 2 working stoplamps there.

see I told you I was a dumb ass

much appreciated.

so the supra has a dud bulb light on the dash does it? how cool is that? No more shall I get pulled over... for having a bulb out :littled:

All the components are behind the trim panel in the boot.

n/c is not connected

In order to convince the bulb failure unit, the resistors need to draw roughly as much current a 2 x 21w stop bulbs. as the resistors only have a max rating of 10w you need 4 of them. Using 4 x 15ohm resistors you use approx 36w, which is enough to fool the bulb failure unit that there are 2 working stoplamps there.

I've fitted 3 x 33 ohm 10 watt resistors inorder to fool the car into thinking it has rear lights (now using L.E.D's) and my god do they get hot, or have I done something wrong????

Hi all, I'm looking to do this conversion soon, so I nipped of down to Maplin to get all the bits. I found the resistors, but which relays do I need, Maplin list 2 different 30A Auto relays

1 SPDT (Single pole double throw)

1 SPNO (Single throw Normally Open)

both look to be a similar rating. Which is the one I need?

Also for any additional wiring what gauge of wire do I need?

has anyone got any photos of the wiring to get a feel for where they position the relays.

Thanks in advance

Mike

you need 2 x spdt. I used 15A cable from Halfords, getting several colours makes life easier

5A cable should be sufficient if you are using 4x15Ohm resistors. Combined resistance is 3.75Ohms, so the current when the engine running will be approx 14 / 3.75 = 3.73A max.

thanks for the replies guys.

I managed to get the wrong relays the first time round

I'll give this a go at the weekend.

Mike

OK, I have managed to do the conversion as per the wiring diagram in this thread. I have the four resistors in parallel, yet when I switch the fogs on I still get the bulb fail light. I was under the impression the resistors would fix this, can anyone suggest what I might have done wrong?

I am quite happy to use the bulb fail light as a tell tale, I'm just concerned I might have done the wiring wrong, and I'm therefore a little nervous.

thanks

Mike

Pixelfill,

I just bought all the components and wired them up together.

At the moment though I don't have my car, so I can' t test it.

Have you got an image of the resistors and how you wired them to the rest of the components for comparison?

Monkey,

I have a couple of photos of the install, they aren't very clear of the wiring of the relays though. The photo of the overall installation didn't have the resistors in, because the bulb fail circuit wasn't working so I took the resistors out. The close up has the resistors in.

I have used blade connectors throughout the install which gives me the option of removing the circuit and reverting back to the old method if I need to (Hope that I won't). The photos of the Light harnesses show this if you are at all interested.

The keen eyed amongst you will note that the left_loom.jpg shows the right loom, and vice versa (oops)

Has no-one any suggestions as to what I might have done wrong. The only thing I did that I can think might make the difference is that I connected the earth from the right bulb circuit to the earth of the relays (piggy backed onto pin 86) rather than direct to ground.

Cheers

Mike

(PS. post 100 - yippeee)

nice one.

That looks pretty similar to what I've done. (hopefully I'll fit it at some point next week)

Did the resistors get hot when you livened up the fog lights?

I spoke to an electician friend of mine and he seems to think that it would be a good idea to use a separate earth. I think this was primarily because the diagram says so.

But I would think that this earth was carrying quite a current anyway and so you wouldn't want to connect it through the other earth, but then I'm no sparky. (This electrical stuff is a funny old game )

as soon as I have put it in, I'll let you know.

I'll try the seperate earth tonight then, see if that makes a difference.

I haven't left the resistors in for any length of time since they weren't doing what I thought they would, primarily because I was concerned about heat. Until I get the bulb fail light to (not) work I'm happy to use it as a tell tale, and remove the resistors.

Mike

any joy with that pixelfill?

Sorry, I haven't had a chance to check it out yet, it's been absolutely chucking it down the last couple of nights.

I'm presuming that I'll need to wire it to a seperate ground point.

I'll keep you posted

Mike

ok, cool.

been chucking down over here too, damned British weather

Right, I've moved the spliced earth (top right of wiring diagram) so it's no longer piggy backed onto pin 86, and is connected directly to the chassis ground in the middle of the boot. This is currently the same earth point as the rest of the wiring. With the resistors in the circuit the bulb fail warning light still comes on when the fogs are on. I'm really stumped as to why. Should the top right earth be at a different chassis ground?

Can anyone point me in the right direction as to which part of the circuit is likely to be the culprit. If I can't get this sorted soon I'm going to throw the resistors away permanently and live with the bulb fail light.

Cheers

Mike

Mine is wired up exactly as in the circuit diagram and works fine. The only thing i can suggest is changing the value of some of the resistors. Maybe some of the bulb fail units are more sensitive than others.

Right,

Just thought I'd post to let everyone know it all works now. I checked the circuit over fully. The problem turned out to be a loose crimp on the earth from the light cluster.

Top marks to TRL and whoever added the bulb fail light circuitry

Mike

I have finally put my fog light conversion in and a few points that are probably worth noting.

Firstly, the bulb fail indicator only works when the car is running.

Secondly, there are 2 greens and 2 green\whites coming out of each light cluster, 1 of each of these goes to each of the brake lights and they are joined into 1 not long after they appear in the car through the rubber boot. I firstly joined the single 1 into the fog light conversion circuit. I then had 4 fogs and no brakes. dumb ass

So just to clarify, pick 1 of each of the 2 colours coming from the cluster and join that to the circuit.

Just thought I'd save someone making the same mistake I did.