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i've got dim lights - any ideas?
john_p_b - 18/1/13 at 08:59 AM

on my indy, both front and rear lights are pretty pathetic but i don't know why. there's 12v+ at every bulb holder and all earths are good, i've fitted the correct wattage bulbs and even checked at one point that i'd not used 24v items!

makes no sense to me that i have perfect voltage but they're still really dim. anyone suggest anything i may be missing?

loggyboy - 18/1/13 at 09:04 AM

Are the feeds directly through the switch or a relay?

john_p_b - 18/1/13 at 09:05 AM

straight through the switch

loggyboy - 18/1/13 at 09:19 AM

Try a relay test, just wire one up temporarily with a relay and I would hazard a guess you will see a drastic improvement.

john_p_b - 18/1/13 at 09:21 AM

i'll give it a try. stupid question of the day perhaps but why will this make it better?

loggyboy - 18/1/13 at 09:31 AM

Switches can give resistance, a relay will give less.

renetom - 18/1/13 at 09:53 AM

Hi
Disconnect anyone of you lights from the car & try it directly to a 12v battery ,
If its bright enough , then it's definitely your wiring, power drain somewhere.
There should be relays for the headlamps at least.
Or you could be loosing it through the switch or a link somewhere.
It very difficult to diagnose without being there.
Maybe someone local to you can help.
Good luck
René

Is this on a new build or an existing car ?.

MikeRJ - 18/1/13 at 10:12 AM

quote:
Originally posted by john_p_b
on my indy, both front and rear lights are pretty pathetic but i don't know why. there's 12v+ at every bulb holder and all earths are good


Is there still 12v (or more) across the bulb holder with the lamp in place and switched on?

adithorp - 18/1/13 at 10:26 AM

Certainly could be any of the above, but first check the earth.
Could be a poor earth to the chassis from the lamps or (as it's effecting both sides) they're wired up incorrectly. With the earth attached to the wrong terminal they'll glow dimly. The earth on an H4 bulb is on of the side ones,and conecting it to the middle one is a common mistake (saw a factory built MNR like that recently).

ashg - 18/1/13 at 10:32 AM

If your using sierra stalks your headlights and full beam need to be on a relay the stalks are not designed to flow the current required for the lights, they can only manage the small current required to turn on the relay.

john_p_b - 18/1/13 at 10:36 AM

i've used durite switches through out.

JimSpencer - 18/1/13 at 10:48 AM

Hi

Somebody who shall remain nameless once wired a set of headlights in series instead of parallel..

Daddylonglegs - 18/1/13 at 10:58 AM

Sounds like an earth issue to me, but I've been wrong before.....well lots actually!

I agree though, wire direct to the battery first then trace back from there if OK.

[Edited on 18/1/13 by Daddylonglegs]

john_p_b - 18/1/13 at 11:00 AM

quote:
Originally posted by JimSpencer
Hi

Somebody who shall remain nameless once wired a set of headlights in series instead of parallel..


i used a vicky green loom (we are going back a few years here!) so correct wiring shouldn't be an issue surely?

adithorp - 18/1/13 at 12:21 PM

quote:
Originally posted by john_p_b
quote:
Originally posted by JimSpencer
Hi

Somebody who shall remain nameless once wired a set of headlights in series instead of parallel..


i used a vicky green loom (we are going back a few years here!) so correct wiring shouldn't be an issue surely?


Could still be the terminals connected wrong on the bulbas I don't think they come with the connectors fitted. Looking from the back of the bulb, the earth should be on the left terminal. If it's on the middle term' them it puts both filaments in series and you get a dim light.

If it was previously OK then it shouldn't be that so...
A) check the switch/feed side by supplying 12v direct to the bulb.
B) if still the same, try a direct earth from the bulb to battery to check if it's the earth.

dhutch - 18/1/13 at 01:29 PM

If it where me, with a bulb in the holder and it turned on, engine running.
- Measure the voltage accross the battery (should be about 14.8v)
- Measure the voltage accross the bulb (shouldnt be much less, but if there dim, i expect it is.
- Measure from bulb +ve to battery +ve
- Measure from bulb -ve to battery -ve.

Measuring without a bulb in is pointless, as the open circuit voltage with no load will not show much up.

But with the above infomation you should be able to determine what the voltage drop to the bulb is, and if its in the +ve feed or the -ve earth. If its in the earth, go through and test that for bad joints, or thin wires. You can test the drop over a certain wire. Ditto the +ve feed, testing the drop over the switch, and or, back to the battery. If theres an fairly equal drop on both, distrobuted evenly over the wires, they are just all too small... and led's might be the best option!


Daniel

britishtrident - 18/1/13 at 01:37 PM

As above try to track down where the voltage drop is.

Just to add some bulbs imported from eastern Europe are not up to much.

Some cheap DMM read high when the DMM's internal battery is on its' last legs -- check it against a known

Dingz - 18/1/13 at 01:44 PM

quote:

If your using sierra stalks your headlights and full beam need to be on a relay the stalks are not designed to flow the current required for the lights, they can only manage the small current required to turn on the relay.


The early Sierra didn't have a relay, the stalks switched full power.

loggyboy - 18/1/13 at 08:32 PM

quote:
Originally posted by Dingz
quote:

If your using sierra stalks your headlights and full beam need to be on a relay the stalks are not designed to flow the current required for the lights, they can only manage the small current required to turn on the relay.


The early Sierra didn't have a relay, the stalks switched full power.


And theres a good reason why the changed!