Losing your under-bumper foglight

[Nick Moss]

I have just done this modification on one of our backdates, which of course will need a rear foglight for the MOT despite looking like a 73 2.8 RSR. The under bumper foglight wouldn't look right at all. The foglights are removed and the wiring taken into the offside rear light unit and connected to the reversing light and a red LED lamp fitted.

 

U38235R (382) 35 Red Led Single Filament Ultra Wide Angle @ £8.99 from http://www.ultraleds.co.uk

 

 

 

 

[nick]

Nice job Nick

[oliverjamesthomas]

Very timely post; thnks Nick! I was just starting to search for the bits to do this modification.

[Von Twinzig]

The LED in question has been superseded by this one now. Red LED

 

Apparently less is more in the LED world so this one is brighter.

[pedders]

With the MOT looming, I thought I'd better get this mod done. Unfortunately something has gone wrong, and any suggestions would be greatfully received!

 

What I have done so far is disconnect the wire leading to the reversing light in the rear light unit, and connect the wires that previously led to one of the fog lights integral to the rear reflector.

 

There are two wires that previously went to the fog light, one of these I connected to the same terminal leading to the bulb holder for the reversing light, the other I connected to the terminal which is moulded into the light unit itself (along with the wire which was already attached).

 

Nothing's working. When I put the headlights on for the car, the fog light pull switch lights up dim (like it's 'spose too), but when I pull it to switch the rear fog light on, it goes out, when it's supposed to light bright. I have checked that it's not the light in the switch at fault (by swapping the front and rear pull switches), and confirmed that it is not.

 

I have also checked the fuses, and nothing appears to be blown.

 

Any ideas would be much appreciated, as I'm scratching my head big time!!!

[SilverWT]

I did this mod OK on my '84, but there was only one wire going into each fog light. Just cut the one reverse light wire and joined the fog light wire to it and all was OK.

 

but when I pull it to switch the rear fog light on, it goes out, when it's supposed to light bright.

However, on mine you pull the swittch to turn on the front fog lights only (and the light in the switch goes out) and turn it clockwise to turn on both front and back fog lights (and the light in the switch comes on bright).

[tea boy]

Nothing's working.

 

Any ideas would be much appreciated, as I'm scratching my head big time!!!

 

You got the LED wired the correct way? A diode only allows current through in one direction.

[pedders]

You got the LED wired the correct way? A diode only allows current through in one direction.

 

Thanks for the suggestions, all.

 

Tried it both ways. No dice. Also reconnected up the original light units, still not working. What was stupid of me was not to check it was working before I messed with it.

 

I'm starting to think it must be the switch, which per the Bentley manual does not look that easy to get at, as you have to dismantle part of the heater system. I don't think I've got much choice, though, so am planning on swapping the front fog switch (which I'm not using) with the rear.

 

I did this mod OK on my '84, but there was only one wire going into each fog light. Just cut the one reverse light wire and joined the fog light wire to it and all was OK.

 

 

However, on mine you pull the swittch to turn on the front fog lights only (and the light in the switch goes out) and turn it clockwise to turn on both front and back fog lights (and the light in the switch comes on bright).

 

Thanks for trying to help, SilverWT - I think it's different on an 87 car.

Edited July 27, 2008 by pedders

[Lesworth]

Quick question regarding this mod - you lose the reverse light completely by doing this correct?

[GaryH]

Quick question regarding this mod - you lose the reverse light completely by doing this correct?

Only on that side though Shirley ? I guess you could always put your foglight on when reversing to regain some light

[Lesworth]

Only on that side though Shirley ? I guess you could always put your foglight on when reversing to regain some light

Doh! Was thining there is only a reversing lamp on one side. Perfect!

[MarkJ]

Doing this same mod myself, my UltaLED bulb finally arrived the other day, so goodbye under bumper foggies

[Type911]

Thanks for the suggestions, all.

 

Tried it both ways. No dice. Also reconnected up the original light units, still not working. What was stupid of me was not to check it was working before I messed with it.

 

I'm starting to think it must be the switch, which per the Bentley manual does not look that easy to get at, as you have to dismantle part of the heater system. I don't think I've got much choice, though, so am planning on swapping the front fog switch (which I'm not using) with the rear.

 

 

 

Thanks for trying to help, SilverWT - I think it's different on an 87 car.

 

 

Fogs under the valence are earth via the bolt/nut holding them on, hence one wire, post 86 with fogs in the reflector had 2 wires direct to the lamp

[MarkJ]

just delving under the back of the car to do the led reversing light mod. Do i need to remove the rear light cluster to get at the wire to the back of the reversing light or can i cut in to one of the wires that i can see near the right hand side engine mount ? If the latter, which colour wire is it? Im looking at the Bentley book and it looks like its black&yellow ? but not convinced.

Only reason i didnt want to take out the cluster is it seems pretty well sealed in with silicone sealant and would mean breaking that out. I took the screws out and started to tug but can see it would need re-sealing after if i do take it out as rubbers are a bit shot.

[Al_W]

just delving under the back of the car to do the led reversing light mod. Do i need to remove the rear light cluster to get at the wire to the back of the reversing light or can i cut in to one of the wires that i can see near the right hand side engine mount ? If the latter, which colour wire is it? Im looking at the Bentley book and it looks like its black&yellow ? but not convinced.

Only reason i didnt want to take out the cluster is it seems pretty well sealed in with silicone sealant and would mean breaking that out. I took the screws out and started to tug but can see it would need re-sealing after if i do take it out as rubbers are a bit shot.

I've got this job to do too, but it's too dark to start now. Will post if I find anything before you do, but I'm expecting to pull the cluster to swap wires.

Good luck, as I hate electrics....

[MarkJ]

The wires to the rear cluster enter into the back of the bodywork via a multiplug. But with several wires there i wasnt sure which one to cut into. I thought the bentley wire diagram would show one of the wires coming from the reverse light switch on the tranny but couldnt see it on the page. Have left it for now.

[MarkJ]

Anyone know which colour that reverse light wire is coming into the multiplug on an '86 carrera ? Would be quite a quick mod if i can cut into there. Think there are only 4 wires there?

[Von Twinzig]

Anyone know which colour that reverse light wire is coming into the multiplug on an '86 carrera ? Would be quite a quick mod if i can cut into there. Think there are only 4 wires there?

When I did mine (US LHD) it was the Grey/Brown IIRC.

[MarkJ]

Cheers Twinny, i think it is the grey/brown wire. I had a look and there is one visible. Also just found further along in the Bentley book under 'back-up' lights which i take it is american for reversing lights? I think thats the cookie

[Von Twinzig]

Cheers Twinny, i think it is the grey/brown wire. I had a look and there is one visible. Also just found further along in the Bentley book under 'back-up' lights which i take it is american for reversing lights? I think thats the cookie

Yep back up = reversing.

 

I just cut into the wire engine side of the connector and soldered in a new connector.

 

Run the wire through some cable protector either the hard spilt spiral or the expandable poly prop tubing, for a bit of protection.

[MarkJ]

one other question from a spanner chump :- should the grey/brown reverse light wire be disconnected once the fog wire put in-line or do you just leave it connected so that the fog also acts as a red reverse light to compliment the n/side reverse light when reversing?..or would that be an MOT fail?

[Von Twinzig]

one other question from a spanner chump :- should the grey/brown reverse light wire be disconnected once the fog wire put in-line or do you just leave it connected so that the fog also acts as a red reverse light to compliment the n/side reverse light when reversing?..or would that be an MOT fail?

Nope, cut it. You only need one fog and one reversing light.

[OCD]

just delving under the back of the car to do the led reversing light mod. Do i need to remove the rear light cluster to get at the wire to the back of the reversing light or can i cut in to one of the wires that i can see near the right hand side engine mount ? If the latter, which colour wire is it? Im looking at the Bentley book and it looks like its black&yellow ? but not convinced.

Only reason i didnt want to take out the cluster is it seems pretty well sealed in with silicone sealant and would mean breaking that out. I took the screws out and started to tug but can see it would need re-sealing after if i do take it out as rubbers are a bit shot.

 

Mjonzo

 

I too in the throws of this mod, i'll attach some pics of my effort.

 

I removed the rear light cluster, took a bit of wiggling, held tight with age and road muck, only to find the 2 screws securing the back cover on the light cluster seized solid -see pic,

 

 

 

So rather muller those screws, i thought i'd try plan B and tap into the wiring, just inside the O/S/R engine bay see pic

 

Now thats as far as i got !..... bit of an anti-climax i know !!

 

I have tried fitting the LED bulb to the reverse light to test but i'm not impressed with it's brightness maybe i have the wrong type but have put things on hold for now, till things get a bit warmer, Yep southern woose

[Von Twinzig]

Guys, sorry should have mentioned that trying to get the back off the light unit is masochistic heaven. From previous experience I didn't even try that this time, just undid part of the loom and cut in.

[mean in green]

I started out with the reverse light mod then ended up removing and totally stripping and refurbing the housings...