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MG Midget and Sprite Technical - NMC zenon hid failure.

My SAAB 93 AERO has Zenon hid dip headlights.
The R/ H side has failed.
Got garage to replace bulb ((lamp) but no good.
I have now removed the front end bumper ! and headlight unit to replace the ballast unit - still no go.
There was a little minor corrosion on the ballast connection so I cleaned it up with contact cleaner and fitted the new ballast - all looked good but failed to light.

There is a 5 pin relay in the fuse box it’s labelled R14 washer fluid pump *, headlights - don’t know what this controls - it’s 5 pin and I reseated it also.

I have it provisionally booked in next week with an auto electrician but hate to be beaten by it.

Pic of relay.






richard b

I'm guessing the relay operates the headlamp washers.
Dave O'Neill 2

Yes I thought that but would have expected a headlight relay as well somewhere as the mains are halogen?
Don’t know where else to look with modern style canbus etc.

Oh forgot to note safety - I have disconnected the battery each time and allowed at least 30 minutes for the capacitors to discharge etc as recommended.
richard b

No relays on them , the relay you mention is for the headlight washers as Dave mentioned.the fuses for the parklights are for the headlights as well but they're a bit weird one does low beam on one side and hi on the other then the other does hi beam on one side and low on the other---If your parklights are working then the fuses are ok
Has your light failed on both beams on the same side--
Does your light work with flash to pass--

Just a thought--if you already have the bumper off you could temporarily swap the ballast-light assemblies over side to side and see if the problem follows the lights(ballast-light issue) or stays on the same side(car issue)
William Revit

Thanks Willy
Yes my plan when it stops raining is to plug the near side light unit into offside (right side) to see if it works ok and prove if it’s a supply issue further up the system or not.
Then to try the right side unit in the left to see if it works ok

The flashers work but I think they are the halogen main beams which were working last time I checked and the mains were working ok - just the Zenon hid dip failure.

I always find it rather amusing to be getting excellent advice on my problems from the other side of the world !

Many thanks as always !

R.
richard b

Richard
Can't help I'm afraid - I'd do what Willy said.
Bill B

Richard--just thinking about your light problem-
Not at all sure about the Saab bus system- but there's a possibility that one of the car's computers has actually detected a fault and turned the light off. If it has done this it would have logged a trouble code
You might have to get someone to plug in a code reader to scan the car's electrics and wipe the code to re-enable it. Also the code should point you to the area of the fault.
Did a warning light set on the dash-if yes is it still lit.--that'd be a sign that it might have logged a code
Canbus can be a real pain in the butt.

cheers
William Revit

Well the weather had a dryer window and I stripped off the headlight and got it in the dry.

Took off the new ballast and found that one of the flat pins was bent and had not entered the coupling ! It had been very difficult trying to get the plug coupling to enter as the new external gasket is really tight in the tube- I even added silicon grease but it took a lot of pressure to compress the toothed gasket.
The unit is marked as Hella as original but on comparing the two the original had the two flat pins slightly below the connecting plug so acted as a guide. The new one had the flat pins slightly longer so not allowing the plug to guide the pins !

So I very delicately straightened it out and ensured it entered as square as possible- it popped in this time !

Refitted the headlight, connected the battery and sat in the seat and said my prayers ! Yes yes yes it lit !

Not sure the washers are working but that’s another day.

Hadn’t realised that when going to mains the Zenons seem to raise the beam as well as the halogens lighting up - no wonder on country roads the lights are good but cut off well on dip !

Thanks again Willy.
richard b

Good to hear that you got it sorted, Richard.
Dave O'Neill 2

Nice work Richard--I bet you had the please, please, going when you were straightening the bent pin'--If that had been me it would have fallen off as soon as i touched it--
Cheers
willy
William Revit

This thread was discussed between 10/11/2025 and 13/11/2025

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