Headlights gone dim

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dks
Posts: 29
Joined: Mon Sep 30, 2013 11:56 am
Location: Brisbane, Australia

Headlights gone dim

Post by dks »

G'day chaps.

A few days ago I got in my car to come home about 6pm and no headlights. Well, so dim there might as well have been nothing!

So, we get out the ETM for 87 models and page 6312-0 and -1 aren't correct for my car. I have a UK import with H1 bulbs - I guess the ETM is for US sealed beam versions.

Anyway, I traced the connections and here is a picture of updates for these 2 pages for anyone with halogen globes.

ETM updates - 6312-0.png
ETM updates - 6312-0.png (421.05 KiB) Viewed 3338 times
ETM updates - 6312-1.png
ETM updates - 6312-1.png (266.1 KiB) Viewed 3338 times

Once I got that sorted, back to working out why the dim headlights.

I'd read elsewhere to run a jumper from a live point to the appropriate fuse.

So, I went from K4:86 (Hot in run/start) to lamp side of fuse 13 & 14. Still dim - WTF.
I checked the resistance from fuses 13&14 to ground through the H1 bulb - about 3 ohms. Sounds about right for 55w globes.

To make matters worse, time to finish for the day so I put the relays back and tested for fun - all good. Again - WTF.

I'm sort of happy that things are working again but can anyone give me any clue to what is going on here ?

Also, I'm seeing 1k ohms from K4 to K8 (fog light relay) - any thoughts?
'87 635
'84 323
dks
Posts: 29
Joined: Mon Sep 30, 2013 11:56 am
Location: Brisbane, Australia

Re: Headlights gone dim

Post by dks »

Stopped working again almost immediately and I've now worked out where the problem is.

Big voltage drop between fuses 13/14 and the headlights - 5 1/2 volts - ouch.

I see there are some pages on lights in the mye28 forum - so I'll look for some upgrade ideas given I need to do something anyway.
'87 635
'84 323
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MrE
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Joined: Fri Aug 04, 2006 10:37 pm
Location: Capital City, Australia

Re: Headlights gone dim

Post by MrE »

Gday mate

Wish I could help - but I don't really know!!

Glad you've found some info at mye28 - let us know how you get on.

-Ellis
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baders
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Re: Headlights gone dim

Post by baders »

Did you replace the relays dks ? Could be high resistance across the contacts.
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dks
Posts: 29
Joined: Mon Sep 30, 2013 11:56 am
Location: Brisbane, Australia

Re: Headlights gone dim

Post by dks »

Hi baders,

Yep replaced them - had a few new relays to try from. No difference.

I found that the big voltage drop was between the fuse and the globe.
Pulled the fuse/relay box out and saw that there was another connector under the fuse box. Negligible resistance from the fuse post to the female side but there was a good bit of resistance from the male side to the globe. So I still don't know where the problem is - could be this connector, the cable or the connector at the headlight.

Put it back together to ponder the alternatives and full brightness - I'm wondering if the connector under the fuse box needed a reseat. I've checked it few times over the couple of hours and still okay.

I'm not yet convinced this is the problem and hope the b.. doesn't go dim on me one night - at least not with my wife in the car with me :D

I'll report back in a few days.
'87 635
'84 323
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