Problem: High beam doesn't work on outer headlamps!

Thijs Leuven

Thijs Leuven

Active Member
Hi guys!

I've run into an electrical issue with my P6, just a week before it has to go for it's final MOT. How delightful. :rolleyes::p

I'll describe it the best I can.

Low beam: both outer headlights work, as they should
High beam: only the inner headlights work, outer ones turn off
Flash high-beam: doesn't work
The HIGH BEAM indication light in the dash turns on when supposed to.

I've checked the lever on the steering wheel. All the contacts seem clean and there's 12V where it should be. The wiring at the front end of the car seems okay, but I don't suspect the problem lies there anyway because both of the headlights have problems.

I'm suspecting the fuse box. I checked the fuses, they're all intact. The fuse holder for the Main Beam INNER has gone a bit... melty. As it does on a lot of these cars. However, it still works as it makes a good connection.

When I look at the wiring diagram, there seems to be a connection between the two fuses that control the inner and outer lights for the main beam. Is that correct? If so, is that on the back of the fuse box, and could I make a new connection easily? I can imagine the heat causing some damage in any soldering connections there. Looking at the diagram however, I don't understand why my high-beam flash doesn't work having said what I just said...

Any thoughts on this? Cheers guys!

wiring diagram
 
Are they the original lights, or at least original-style lights? It sounds a dozy question and is most unlikely to be your issue but I have come across a replacement halogen set up, many years ago (a 4 headlight set-up but not on a P6) whereby only the inner lights were main beam, the outer units being dip only.

I can't recall anything else about it, just that it struck me as odd at the time. Of course, if yours previously worked as originally intended, then you can rule it out. It doesn't answer the non-working headlamp flasher though.
 
Hi Thijs,

From experience I have had the high beam flash not work, but everything else working as it should. The flash part of this is controlled by the contacts within the switch in the steering column. Mine were burnt from arcing (happened well before I had relays for my high beam lights). Replacing the switch restored the high beam flash operation.

Ron.
 
Sounds like a fuse issue to me.

The brass fuse holders you can see are not all the same. Some are just like a wavy spade clip, and others are two wavy spade clips in one piece. The feed comes into the top of the fuse through one side of the holder.

If you look at the two fuses in the attached diagram 28 and 29, the power comes in to the left hand side of 28 when you use the flash, and the right hand side of 29 from the light switch. The right hand side of 28 and left hand side of 29 is one piece of brass. So effectively the tops of the fuse itself is part of the circuit. Similar to the fuses 21 & 23 below, the power comes down the brown wire, into the top of fuse 21, then through the brass one piece inner clip, then into and down through fuse 23. I hope that's understandable :hmm:

fuse holder.jpg

The two sides of the brass fuse holders are not physically connected, the springiness is supplied by the plastic fuse box, so if it gets hot this can be lost and your connection can be weak even though it looks ok.
 
I assume you speak of the Series 2 fuse box? Somebody out there sells little steel U shaped clips that slip over the sides of the fuse holder metal parts - see
FUSE BOX FUSE CLIP REPAIR STAINLESS STEEL - GBP3 each! GBP 72 for a full Set! Cheaper to put relays on the lights.
I made an equivalent out of 1/32" piano wire I happened to have for almost nothing. These will provide direct conductivity from one side of the fuse clip to the other. You would need to detach the fuse board from the bulkhead to fit these. I also wipe everything electric in the car with Deoxit.
 
Thanks for the replies everybody! :D

harveyp6 said:
Sounds like the main beam filaments in both outer headlamps have failed.
Click to expand...

Could be, I'll check it! Would mean both of them failed at exactly the same time though...

tonys said:
Are they the original lights, or at least original-style lights? It sounds a dozy question and is most unlikely to be your issue but I have come across a replacement halogen set up, many years ago (a 4 headlight set-up but not on a P6) whereby only the inner lights were main beam, the outer units being dip only.

I can't recall anything else about it, just that it struck me as odd at the time. Of course, if yours previously worked as originally intended, then you can rule it out. It doesn't answer the non-working headlamp flasher though.
Click to expand...

Original lights, and they worked fine in december! But thanks for thinking along. :)

SydneyRoverP6B said:
Hi Thijs,

From experience I have had the high beam flash not work, but everything else working as it should. The flash part of this is controlled by the contacts within the switch in the steering column. Mine were burnt from arcing (happened well before I had relays for my high beam lights). Replacing the switch restored the high beam flash operation.

Ron.
Click to expand...

I had a look at the switch, and it all seemed fine. Cleaned it up with a bit of sandpaper but it made no difference... I'll keep it in mind though, thanks for replying.

quattro said:
Sounds like a fuse issue to me.

The brass fuse holders you can see are not all the same. Some are just like a wavy spade clip, and others are two wavy spade clips in one piece. The feed comes into the top of the fuse through one side of the holder.

If you look at the two fuses in the attached diagram 28 and 29, the power comes in to the left hand side of 28 when you use the flash, and the right hand side of 29 from the light switch. The right hand side of 28 and left hand side of 29 is one piece of brass. So effectively the tops of the fuse itself is part of the circuit. Similar to the fuses 21 & 23 below, the power comes down the brown wire, into the top of fuse 21, then through the brass one piece inner clip, then into and down through fuse 23. I hope that's understandable :hmm:

View attachment 18700

The two sides of the brass fuse holders are not physically connected, the springiness is supplied by the plastic fuse box, so if it gets hot this can be lost and your connection can be weak even though it looks ok.
Click to expand...

That's what I was thinking about the fuse box when I had a look at the diagram. Thanks!

jp928 said:
I assume you speak of the Series 2 fuse box? Somebody out there sells little steel U shaped clips that slip over the sides of the fuse holder metal parts - see
FUSE BOX FUSE CLIP REPAIR STAINLESS STEEL - GBP3 each! GBP 72 for a full Set! Cheaper to put relays on the lights.
I made an equivalent out of 1/32" piano wire I happened to have for almost nothing. These will provide direct conductivity from one side of the fuse clip to the other. You would need to detach the fuse board from the bulkhead to fit these. I also wipe everything electric in the car with Deoxit.
Click to expand...

Together with quattro's thoughts, this makes the most sense to me. I'll dive into it! 3 quid for a tiny bit of bent steel, I'll see what I have lying around in the shed! :p
 
Yes, I know about that conversion. A lot of work and I don't really like electrics... :confused:o_O Very good solution though, if nothing else works this is a great option! :thumb:
 
The little clips will need to be springy like piano wire to do the job. The gap needs to be such that you have to force the clip over the fuse clips, and its tight enough to stay there. You will get piano wire at a hobby/model shop in various diameters.
 
Just to clarify, these are actual series 2 fuse box fittings. You can see where the power comes in and needs to pass through the cap of the fuse on the right, then through the centre brass fitting and into the fuse on the left.

This has been known to cause confusion as removing to right hand fuse cuts power to the left one, so the stuff that you know runs from the left hand one, stops working when you remove the right hand one :hmm:

IMG_6146.JPG

IMG_6147.JPG
 
The top picture helps a lot quattro, thanks! Am I correct in thinking the way its portrayed is like it's fitted into the car?
 
Yes, the one on the left would have a feed to it from the headlamp flasher, and the one on the right with the wire in it now would be from the light switch via the full beam switch.
 
Yes! This is where the little wire clips can help to remove this anomaly by electrically joining the 2 parts of one fuse clip.
 
We bodged it for now, but I have high beam! :D

Turns out the fusebox was the issue. Joining the two fuses together via a wire restored the high beam. Since the MOT is this week, we tried our luck and soldered a wire in between the fuses themselves. After that I placed them back carefully, and it works! It's nowhere near a good solution, but for the few seconds that I'm going to need high beam this week, it'll do. After that I'll look into a more permanent solution. ;)

Oddly enough, the flasher still doesn't work. Can't quite get my head around that. :hmm:
 
Happy to say she passed her final MOT with flying colours! They absolutely loved the car. Only slight remark? Some minor oil leaks. But hey, it's a 70s BL product. What could you expect?! :p
 
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