Thread: D2a light problem

Sound a little like you got sold a dodgy globe

Sounds like your steering column switch is on the way out.
I recall a thread here recently that describes how to pull the switch out and refurbish it. Try the search.

Originally Posted by biggin

Sounds like your steering column switch is on the way out.
I recall a thread here recently that describes how to pull the switch out and refurbish it. Try the search.

Thanks Biggin, the switch controls both headlights, but one side behaves normally.

Have you checked the connector into the light unit?
Track back from the globe and see which terminals are your 12v +ve for high and low and check the plug terminals using a panel or somewhere not the body or engine for earth.
Sounds more like a bad connection somewhere.

Your options are:
Faulty globe
Faulty harness.
Faulty Fuse

1) Confirm globe is OK:
You have one globe working, use this harness and plug in the replacement globe.
It either works or doesn't.
Throw the globe if it doesn't work and try another.
Globe works? goto 2...

2) No power to the beam?...confirm the fuse is OK...change it.
If the fuse is OK, or the fuse blows straight away, then there is a break in the harnes somewhere.

3) confirm the harness,

Use a circuit tester ( a $5 probe with a globe in the handle and a wire out the back to earth) to confirm power is available at the harness.
No power...In this case, you need to follow the harness back to see where the break is...or make a supply via a relay from the know good supply from the other light.
Set up a standard relay and use a tie in from the known good low beam to switch in the relay to supply power to the other...you may need to cut back the original supply to protect from back feeding, but that can always be re-joined if you ever find or repair the harness break.

The earth point is not an issue if you have power on one beam (proved by the globe in step 1 and as per your text) as the earth in the harness is common to both beams.

The switch will be OK assuming there is power to all other lights. The switch simply takes a live source and couples it to a single out line to the lights. The speration of circuits is after the switch.

Originally Posted by Nicky

Hi all,
My 2003 D2a TD5 has the right low beam headlight out, high beam OK. Changed bulb did no good. Fuses OK.
Tried it in the left connector, same, only high beam working.
Put the lights back correctly, now the right headlamp has no low or high beam.
Stumped?

Am I correct in my understanding that you took the troubled RH light and plugged it into the LH harness and it still had no lowbeam?

If so it is either

• Still a globe issue (try another)
• Actual plug on the back of the light cluster (test continuity between the correct pin in the plug and the pin in the plug for the globe inside light)
• Harness inside the light (as above)

It's difficult to get a handle on what the symptoms are here. If there is no low beam on either side (as stated previously) then probably the switch is the problem.

If the low beam on the other side works only with one globe, then obviously the other is u/s. I discounted this, as it is too obvious for anyone not to consider.

What happens when the globes are swapped from one side to the other?

Without knowing exactly what is going on, it could also be the connector on the wiring harness end is not properly inserted into the connector.

Thanks all, turns out bad connector, wiggled, opened and closed, and all OK now, gives you such confidence in English electrics?