Headlight failure - ZTT V6 190bhp (2004 pre-facelift)

[Monte Carlo]

Hi all,

Help and guidance required!

The other night my n/s dipped headlight bulb failed and 10 minutes later, having switched engine off and on again, the o/s dipped headlight bulb also failed. How strange!

Having just changed the bulbs, the n/s still doesn't work. Furthermore, the sound of a motor/relay can be heard from the o/s but not from the n/s?

Any ideas?

PS. the garage had the front bumper off about 3/4 weeks ago and I understand its possibe for wires to be chaffed affecting the o/s light. Can chaffed wires on the o/s affect the operation of the n/s light?

PPS. what a b****r changing the n/s bulb was! Couldn't budge the air feed intake scoop so had to unscrew fuse box and went in from the top. Would'nt fancy doing this at the road side in the dark!!

[JohnDotCom]

:welcome: Monte Carlo. Wires being Chaffed is Common and sounds like it could be your Problem. Have you done the normal Fuse checks? When members wake up Im sure you will get some more Helpful Advice.

[Kandyman]

Welcome to the forums Monte Carlo,

As you have found out it could be the chaffin of the wires or they got trapped from when the bumper was replaced.

What work was you having done to have your bumper off ?

[MartinW]

Incidentally, I have found that twice, my o/s and n/s dip bulbs have failed within days of each other! Bulbs seem to last me a matter of 18-24 mths at best.

That said, I have had my car front end apart this last weekend and each headlight unit is fed with two separate looms.
You can see some of this here (http://www.brit-cars.com/mg/zt-zt-t/bumper-removal-fan-motor-replacement.html) in the photographs. I am not sure how that might have caused teh other side to fail, but the whirring may be the level motors struggling to settle if not plugged in correctly - when I refitted my bumper, the headlights took a few seconds to settle.

Strangely, they factory fitted an anti-chafe rubber on the n/s but not the o/s! I have now fitted a o/s rubber, as well as an additional one under the support rail on the n/s for the cooling fan loom.

[CFS75]

Martin, I am intrigued by the reference to the headlight leveling motors.
Do the headlights automatically level every time when they are switched on?
Do all models have this facility?
Looking at the wiring diagram (12.29 diagram 4) in the Haynes manual I can't see any indication of motors within the headlights that would provide movement, although I realize that there must be for the beam height adjuster!
Would a failure of a headlight bulb have any effect on the level motor or vice versa?
Colin.S

[MartinW]

Sorry, wrong terminology, Xenons have self-levelling headlights linked with the suspension, but the std headlights I meant the beam height adjusters - mine seemed to whir up and down a few times when first switching on after refitting the plugs.
I think all cars have to have headlights height adjusters if not fitted with auto-levelling units. As to whether these would be affected by a bulb failure, on two previous events, no, I have not noticed this causing an issue, only this time when re-plugging the headlight looms.

[Keith]

All the various headlights have leveling motor and they should be heard and seen operating when the lights are turned on

Bulbs blowing is not uncommon especially cheap bulbs

Removing the bumper is not the primary reason for chaffed headlight wires as the loom for the headlights is not really related to bumper movement. look at the back of the headlight where the plug goes in you will see the cables seem to rest on the raised seam of the front struts that support the slam panel etc, the cables can be damaged here so look for cut through wires, repair as necessary and fit something to prevent further chafing

[Monte Carlo]

Thanks very much for all your helpful comments. The investigation continues!

[Monte Carlo]

Further update - headlights now working.

It appears that when connecting the wiring plug to the bulb I must have made a bad connection. Easily done when you can't see what you are doing!

As a matter of interest, can anyone tell me why the headlight bulbs/holders move inside the headlight when the lights are initially activated?