Dim offside headlamp

[crafti]

One of my headlamps is dim, and the high beam not working, just on that one side. I've checked the bulb, as well as swapping the whole headlamp. Clearly an electrical fault on the car, any suggestions??

Cheers
reef

[Nige]

bad earth? check the fuses you have one for each side?

[crafti]

bad earth? check the fuses you have one for each side?

that was quick, really appreciate it.

"bad earth" - would that be a bad earth in general, or just for that particular light? There's three wires to the back of the headlamp, how do I access them beyond the back of the light housing?

fuse, one for each, didn't realise that. If it were the fuse, would that not put out the light entirely, rather than just high beam?


May I also apologise in advance if some of my questions are stupid. While I can pretty much rewire a house, I struggle to get my head around auto-electrics. .

Cheers
reef

[impmad2000]

A bad earth on the head light sounds likely.
A dead fuse would prevent the lamp from lighting. The fact that it is dim indicates that the earth return is via the other half of the bulb !
Loop a temporary earth from the lamp to the battery earth to check it out.

Cheers
Tim

[tanick]

I think each side has a fuse just for high beam. Mine burnt out the first day I had the car. I should have got the hint then!

[chris68]

Hi,

If the fusing is anything like my '68 car there will be individual fuses (4 off) for right low beam, left low beam, right high beam and left high beam. However, given that your problem is common to one side it doesn't sound like a supply side problem. I agree with the other replies that a poor earth return will be the culprit.

I think the right and left front lighting harnesses each have their own earth returns which terminate to a stud near the battery. I'd check the continuity of the earth return on the side that's giving the problems.

Cheers,
Chris

[crafti]

Right on the nail. The problem was the earth to the stud near the battery. I've bypassed it and everything is back, including the high beam. It does have 4 fuses but all fuses were OK. I get why it was dim on low but I don't realy understand why this stopped the high beam. Anyway, you guys were absolutely right .

I've made a pretty good fix but I would really like to fix this properly. Anyone know where I can get a lighting harness (right hand side)????

Thanks everyone, comments have been extremely helpful and I've got light. And to top it off, complimentary modification, I popped some RHD lights on at the same time, so I've now got lights again but this tme, the right ones.

Cheers
Reef

[chris68]

Hi,

I'm pleased you've sorted it. The main beam probably didn't work at all becasue it draws more current than low beam. The poor earth stud connection would create circuit resistance that dropped volts when current flowed (V=IxR). The high main beam current would create so much volt drop across the earth stud that the light didn't come on at all.

As far as a new harness, I can't help. But, you can get the bits to make your own from the company below. Give them a call and they'll send out a catalogue. You may need to equip yourself with some crimps, a soldering iron and a cheap multimeter.

Vehicle Wiring Products
9 Buxton Court
Manners Industrial Estate
Ilkeston
Derbyshire
DE7 8EF
Tel. 0115 9305454
E-mail. sales@vehicleproducts.co.uk

Cheers,
Chris

[crafti]

Thanks for the explanation, which now makes perfect sense to me. I'm glad you spelled it out because it was actually irritating me not knowing, even though it's fixed.

The wiring company has an online cataloge, and I can find everything necessary except the part that goes into the luggage compartment near the battery (the part we referred to as the stud). That's the vital bit as the rest needs to plug into it. Any ideas?