Headlight Conversion Options

Phil Robson

Well-Known Member
#24
My Series 1 V8 has halogen lights fitted
I'm refurbishing 'Hazel's' front end whilst I'm changing the radiator & thought about wiring some extra LED sidelights into the halogen bowls. I have LED bulbs in the actual sidelights which are MUCH brighter than the originals & I'm thinking some in the outer headlamps will make good 'running lights' that every car seems to have these days. I'm getting concerned that my P6 doesn't standout any more against traffic with such lights.

Anyway, these are the backs of the headlamps with a suitable old-style bulb & holder. Can anyone tell me what to look for to get LED replacements that will fit these holes? I thought it would be easy, but can't find anything like.

IMG_6535.JPG
 

jp928

Active Member
#27
Quattro, can I ask how you physically tapped power off the big lead at the light switch please? On my 74 S its item 40 in the wiring diagram - 86.00.01 Sheet 5. The big brown/white lead is connected with a 3/8(10mm) female spade , and I dont have anything this big - 1/4 or 5/16 is OK, but not 3.8". Not sure that tucking a lead up into a curl in the connector will connect well enough to do the job safely. There is also a bare male bullet on a purple wire hanging loose in there - is this common/normal? I cant see anything that I night have pulled it out of.
thanks
 

jp928

Active Member
#29
I have some female spades with males attached to duplicate a connection, but no sign of these bigger than 6.3mm. Night have to do as you suggest - safe, good connection, but more fiddly than I was hoping for.
thanks
 

jp928

Active Member
#30
I think I am losing my marbles. Doing relays for the headlights and horns. 3 each side. Relays in sockets - two light leads to fire the coil, two heavy leads for input and output. Picked one of the light leads (85) as trigger to be connected to original power feed; other light lead (86) to go to earth, so I connected all 3 leads together at an eyelet/ring. Fed the 30 lead from a small fuse board fed from the heavy lead at the light switch. Fitted bullets to the triggers to connect to the old leads to the lights, and bullets to the output 87 leads to go to the lights. Connected everything up EXCEPT the earthing of the 86 side of the coils..... and the lights worked.... without the 86 being earthed..??? I cant see that tying the 86 leads together is a problem, as they would all have to go to earth somewhere eventually. The lights work correctly, dip and main. For the mains I used one of the two original feeds to fire the relay, and fed both lights from the one output, and left the unused feed inside its insulated connector.
Any ideas how the relay is firing ?
 

quattro

Administrator
Staff member
#31
Try earthing 86, if the lights go out you have the wrong relays :) some are turned on normally, and the 85/86 connection turns them off.

Apart from that, no idea :hmm:
 

jp928

Active Member
#32
They are normally open relays....bought specifically for this. I have some NC relays, but dont know what I can use them on.
 

jp928

Active Member
#33
Got all done this morn. Probably should have gone with fused relays to make it more compact, but I had the relays etc already. LH horn is not working. Connecting the RH horn was a pain - the whole RH area is a PITA due to the booster, but the horn was the worst part. In the end I removed it, made an extension cable to bring the connections up to the top so I could connect them, then tucked them out of the way. Now to fix the LH horn.
Suspect the relays operating without earths is related to the fact they have diodes across the operating coils, but still dont understand whats happening.
 

jp928

Active Member
#34
LHS horn not working, so pulled that off. From the outside the contacts showed open circuit. Drilled the rivet heads off and punched them out. Insides as below. After a bit of abrasion of the points I got a low resistance circuit, so it ought to work. After cleaning up all the crap, I closed it back up with M3 cap screws (had plenty the right length) and nylocs. Success - nice deep note.
 

jp928

Active Member
#35
Further work on the odd relay behaviour. Swapped in ordinary relays in place of those with diodes. The low beam relay will fire without a ground on 85. If I pull the relay so it releases, it wont fire without ground, but once grounded it will stay latched when ground is removed. When I probe the signal leads (ie those leads that used to go direct to the lights but now go to the relay sockets) for resistance I get ~80 O on low beam and horn, but< 10 O on hi beam, all with the light switch at OFF. Surely these should all be open circuit? Does this imply there is a problem at the switch? Cant find the switch part no anywhere on the web - 586704 for S2 S suffix D.
thanks

Update - could the resistance reading be seeing ground through the Hi beam warning bulb?
 
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quattro

Administrator
Staff member
#36
Does it work when you connect it correctly, i.e. switching circuit across 85/86, and power to the light coming in at 30, and out to the light at 87?

Have you tried putting the switch +ve in on 85, and grounding 86?
 

jp928

Active Member
#37
Have concluded from the resistance seen on the hi beam lead that its from the hi beam warning light , providing a path to earth that is enough to fire the relay, because all the earth leads for the relays are tied together. Everything works as expected, so going to tidy up and move on.
 
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