Failed MOT - driver side headlamp

[Bonners]

Hey guys,

For one reason or another it’s been a terrible year for NSX use but wanted to get her serviced and MOT’d just to keep the records straight.

I did fire her up earlier in the year and all seemed fine, but then didn’t connect the charger properly (I assume) so battery died. Sat idle in the garage over the summer as work kicked my backside so had to jump her to get her going and over to Aberdeen Honda.

MOT failed due to an issue with driver side (R) headlamp. Apparently there’s 2 manual knobs for adjusting light position (seized apparently) and also an automatic/motorised adjustment. The solution suggested is to order part # 33100-SL0-E03. Not a cheap part and won’t be delivered until late Feb. Initially I’d thought I could just get a less strict garage to get my MOT pass as I’m a fair weather, maybe 1000 miles, day driver so no big deal. On getting the car home however I hear the motor for the headlamp continually whirrs, when key turned. Stops when I switch off the car…which is why Honda’s suggestion that it was perhaps this motor that drained the battery seems unlikely/impossible. So the headlamp rises and drops no issue, the issue appears to be with the self levelling motor assembly.

Had a rummage through some similar problems and see parallels, but as I’m pretty mechanically inept I thought I would also raise a new query. Please just redirect me if this has been discussed to death and I’ve simply not found the thread yet.

On a brighter note, obviously I drove straight home and did not drive over any of my favourite roads, but even still the car was immense. What a howl as you let the revs climb, love it..

[mutley]

I've had something similar on my last MoT, although we did "cheat" by using the manual wind up/ down adjusters to change the height of the lights. This was only possible as I still had a slight issue with my lights going up and down as they should, and prob won't work on yours as if you try to wind up / down, I think the motor kicks in and put it back to the fully open position. Worth a try though

Cheers,
Jim

[NZNick]

Bonners - the part number suggested to you is for the entire headlamp assembly, which as you say is quite pricey.
The adjuster is available seperately - see part number 33129-SLO-N11
Not sure if this will work in your case, but is about a tenth of the cost of the suggested part.

[RedCarsGoFaster]

Bonners - the part number suggested to you is for the entire headlamp assembly, which as you say is quite pricey.
The adjuster is available seperately - see part number 33129-SLO-N11
Not sure if this will work in your case, but is about a tenth of the cost of the suggested part.

Need to add a clarification here - it isn't made at all clear on parts diagrams, but the part number quoted is the JDM and USDM mechanical adjuster for the headlight assembly. European cars had a different headlight adjuster assembly, with three-position electrical height adjustment from a rotary knob in the cabin. The two headlight adjuster assemblies are not interchangeable between JDM/US and European spec headlights - ask me how I know!

The failure of the electrical adjuster assembly is yet another effect of the dreaded capacitor leakage within the printed circuit board assemblies. This sometimes can be repaired by replacement of the capacitors if the leakage has not damaged the circuit board or other components.

As you've found, the electrical adjuster is not spared separately from the complete headlight assembly. Looking at the parts diagram, I believe it's part of the wiring harness for the headlight, which doesn't even get its own part number. If you're very lucky, the harness might be common between LHD and RHD headlight assemblies, and Christian at ATR might have one from a broken European car.

Depending on how good you are with DIY and electrical, removing the adjuster assembly and cracking it open to attempt a PCB repair by component replacement might be worth your time. I know Kaz does a lot of electrical repairs on NSX parts, and Heineken occasionally posts the results of his handiwork for European owners. You could ask either of them to have a look, or take the adjuster assembly to anyone capable of PCB repair with some guidance notes.

Be warned that availability of European-spec parts is often poor due to the low number of cars made for this market, and the unique combination of right-hand-angled headlights with an electrical adjuster mechanism for the UK market will be the rarest headlight spec of the lot. If you can get a new UK-spec RHD headlight assembly it'll be worth its weight in gold, but I would be worried about Honda's capability to ultimately supply it.

[Nick Graves]

Getting a lot of 'NLA' on those part numbers.

Best to pull out the unit & check that it is actually defective.

If it's just a case of seized mechanical pivots you will save yourself a lot of heartache.

[Kaz-kzukNA1]

This subject always reminds me of the discussion with late goldnsx.

Mine is JDM so doesn’t have this motorised levelling adjuster but from what I heard from him, it's addition to the –A01/-N11 manual adjuster.
The main adjustment is done through the manual adjuster.

From the FB group, one European owner kindly took several photos of the actual electrical components and yes indeed, there are 2 green capacitors leaking heavily.

Some of the failure modes were caused by the gear shaft within this motorised adjuster disintegrated from the mating thread inside the adjuster case.
This will result in motor spinning intermittently or continuously depending on the position of the feedback sliding resistor block.


To pass MOT, you need to have the correct beam pattern/alignment AND if the car is equipped with the adjuster that can be operated from the driver’s seat, this must be operational as well.

So, first try these steps.

1. There are 4 x small 10mm bolts holding the headlight assy/unit.
If you loosen these bolts, there is enough play at the bolt hole that you can make fair amount of height adjustment.
Quite often, you can get the alignment within MOT requirement by this method.
On my garage door, I marked the beam pattern immediately after passing the MOT so I use it as the reference for the next MOT.
My NSX has Type-S suspension and slightly different F/R rake from standard spec so can't be used for other NSX but still, close enough.

To access these 4 bolts, you’ll need to first remove the plastic headlight cover.
When re-installing, first make sure to set the cover as forward as possible before making the final adjustment.
Otherwise, when you raise/pop-up the headlight with the bonnet closed, the edge of the cover may catch the bonnet.

2. With the plastic cover off, check the operation of the manual adjusters. Two at each unit/side.
The long threaded shaft is heavily corroded by now.
When you operate the manual adjuster, this shaft should not rotate.

3. The motorised adjuster is actually at the lower/bottom side of the headlight unit.
If you can, remove the headlight unit (4 x small 10mm bolts, as mentioned above + disconnect the grey connector at the centre).
In order to remove the motorised adjuster, I’m afraid you will need to de-pin some of the terminals from the grey connector unless you are willing to deal with the wires inside the headlight unit.

If you acted early enough, the leaky capacitor may have not damaged the black flat HIC module yet.
The other big module is the motor driver and I think it could be the same one used on the A/C CCU board.

If you manged to remove it, then I can take a look at it.

Kaz

[Bonners]

OMG, I wish I had 1/10 of the knowledge/skills/willingness of some of you guys, and I’m going to have to read those emails a further 3-4 times to make some sense of them. Thanks to all that have pitched in with some ideas and suggestions.
At the end of the day though I can’t do very much, but I am wondering if a mechanic I know can review the suggestions and perhaps have a stab at a repair. Still not cheap, but hourly rate ~2/3 of the Honda dealer. Funnily enough this is the guy that used to look after my first car, Mk1 MR 2 which also had a shagged headlamp!

@mutley- is yours a European car? Honda suggesting my manual adjusters are seized, surely with the right lubricant and a wee bit of muscle that should be addressable. If they’re seized they should be seized in the right position so what’s the fuss :-). I think I can get away with a solution, but not if the motor whirrs incessantly.

@NZnick - that part appears to be part of the bigger assembly. Is your understanding then that this is the part that relates to the motor or is the motor then? Honda said it came as 1 big assembly…although probably been 15+ years since they properly worked on an NSX so don’t blame them for being less enlightened than some of you guys. What do you reckon Kaz

@RCGF - I don’t believe my car has a rotary knob in the cabin but believe my car is UK/euro spec. Perhaps not, is there an easy way to tell? The rest of your message will have me in cold sweats for the next few nights, “crack open the PCB…” ��

@Nick - thanks, something for the mechanic. Hopefully he’s intrigued enough to give it a go, or he might just say I can’t be arsed in which case I’m stuck.

@Kaz - I’m grateful I’m not reading your email and chewing gum at the same time as it might be too much for me ��. So it sounds like my motor is also spinning, constantly when ignition on. Where is this mystical in cabin headlamp adjustment? I’m not home until Friday so can’t check but I just cant picture it. I have a rotary knob for dimming the dash but that’s all I can think of. If I don’t have it, I expect it’s in there somewhere, in theory I don’t need it to pass the MOT, correct? If I do have it, then point 1 is irrelevant though as the motors need to work, regardless of if I can get the headlamps set properly, right? Point 2 x Honda say the two manual adjusters are seized. Point 3 - “depinning” isn’t just a connector but something more complicated I assume? Do you believe I should be able to just buy the motorised adjuster or is the whole assembly required like Honda say/suggest? A little concerned that they may be ordering the wrong part, or perhaps the right part if my car is an import right?

I adore this car, looks immense and by not being blisteringly fast you can actually drive/rev it without doing. “Go to jail” speeds. Season in Scotland is over so I’ve wasted the year but need her operational for 2023 for sure. Again, thanks to all for the insight and guidance. ����

[RedCarsGoFaster]

So on identification of the controller for the headlight adjuster, the European market NSX has four controls on the centre console, behind the gear lever and adjacent to the base of the handbrake.

Three of them are buttons - front fog lights, rear fog light, and headlight washer spray.

The fourth is a rotary knob, which pops up when pushed and can then rotate between the three positions, labelled 0 (intended to be the standard), and then 1 and 2 for downwards tilt to compensate for increasing luggage load in the boot. It will latch down once pushed down a second time.

In the photo linked below, that knob is in the popped up position, available to adjust the headlight aim. When depressed it sits almost flush with the surrounding panel.

https://uploads.carandclassic.com/uploads/cars/honda/18736800.jpg


If I recall the rule correctly, electrical headlight height adjusters, if fitted, must work in order to pass an MOT. As the height adjust knob is subtle and testers may not recognise it, I'd consider that it's rather more likely to fail the MOT for an incorrect headlight pattern.

If the manual mechanism can be freed up and the motor disconnected, an appropriate headlight pattern may be achievable.

[RedCarsGoFaster]

Post for the collective hivebrain - I haven't had the headlights off my NSX in a little while, and don't have any photos of the relevant area of the headlight including the adjuster.

More in hope than expectation I Googled a random collection of words, and found this:

https://www.aliexpress.com/item/1005001933349747.html

It's for a 2020 NSX, but looks remarkably similar to the electrical adjuster motor used on the 90's NSX. I'd be amazed if it's the same, but it's got me wondering if a similar replacement could be found from China.

I'm not in the same place as my NSX at the moment so I can't check, but it would be interesting to see if the headlight adjuster motors actually have a supplier part number on them.

To remove a pop-up headlight is fairly easy - deploy the lights using the push button inside the gauge cluster (not the rotary headlight switch), pull the pop-up fuse in the under-bonnet fusebox, four screws to remove the plastic headlight cover, four bolts to remove the headlight assembly from the pop-up frame. Then it's loose and free to be manhandled, subject to the constraints of the wiring. Turn the unit over and you'll see the height adjusters on the outboard underside of the unit.

Anyone with a Euro pop-up headlight equipped NSX fancy doing some archaeology?

[Nick Graves]

So on identification of the controller for the headlight adjuster, the European market NSX has four controls on the centre console, behind the gear lever and adjacent to the base of the handbrake.

Three of them are buttons - front fog lights, rear fog light, and headlight washer spray.

The fourth is a rotary knob, which pops up when pushed and can then rotate between the three positions, labelled 0 (intended to be the standard), and then 1 and 2 for downwards tilt to compensate for increasing luggage load in the boot. It will latch down once pushed down a second time.

In the photo linked below, that knob is in the popped up position, available to adjust the headlight aim. When depressed it sits almost flush with the surrounding panel.

https://uploads.carandclassic.com/uploads/cars/honda/18736800.jpg


If I recall the rule correctly, electrical headlight height adjusters, if fitted, must work in order to pass an MOT. As the height adjust knob is subtle and testers may not recognise it, I'd consider that it's rather more likely to fail the MOT for an incorrect headlight pattern.

If the manual mechanism can be freed up and the motor disconnected, an appropriate headlight pattern may be achievable.

Indeed - a workaround might be to replace the pop-up switch with a blank, install some square number plates and keep yelling "Yo JDM!" when at the MOT centre...

[Bonners]

Cheers RCGF,
I'm in London for a few days so will check this out when I get home.

Memory suggests I've 3 buttons, I just can visualise/recall seeing the rotary knob, or the headlamp water jet button (what a cool place to put it) ....but I've barely sat in the car this year so could be wrong. However, as I've a whirring motor from the right headlamp I guess that can only mean I do have a euro/UK spec car with the automatically adjusting headlamp unit....right?

That aliexpress part does indeed look like a similar part, and for £10.91, (with a £3.62 discount on orders over a whopping £4.52) it has to be worth a punt ;-)

Deactivating the motor is exactly what I'm hoping to do. From my untrained eye - against the garage door - they looked fine, I bet they are, but I obviously don't want the motor engaged constantly. Anyone know if I can simply pull a fuse to stop it?

I may still get it fixed properly, but this may at least enable me to get an MOT and take her out a few times before the salty roads come.

[mutley]

Sorry for late reply,

yes, my car is a UK spec car. Have you found a solution yer?

Cheers
Jim

[Bonners]

Got home late last night so no, no further forward.

I did however just go and peer in the window and see I have the four buttons in the centre area as was explained denotes a UK/Euro car. Will go and play with the light levelling button tomorrow and see if anything happens. May also pop over to the mechanic, if weather kind, and see if he has any initial thoughts. Will advise once actions taken, thanks.

[Bonners]

Haven’t done much digging but did fire up the car yesterday.

Put the lights up, right hand side whirring away, even before I put the lights up, as is the problem. Fiddled with the little knob between the seats and nothing happens. I didn’t expect the light, on the garage door, to move on the right hand side, but assumed the left light pattern would raise or lower, but it did nothing???

That’s what this button is meant to do, right? Still not been over to the mechanic I’m hoping will take a look but should manage when I get back next week, if the bloody weather eases up!

[Bonners]

Ok have booked my car in with my mechanic on Dec 9th so will hopefully learn more then.

Upon explaining the issue over the phone it struck me that maybe I’m not fully comprehending the issue. Mine is a UK car, with the rotary knob in the cabin to adjust beam height. So even though I’ve never touched the rotary knob for s9me reason, capacitor drain suggested, the motor used to activate the lamp is spinning. As the beam isn’t moving I guess this means the motor assembly has disconnected itself from some mechanical linkage.

If I can reconnect it, is it the mechanical linkage that acts as the shut off to stop the motor? Thanks guys.

[RedCarsGoFaster]

Ok have booked my car in with my mechanic on Dec 9th so will hopefully learn more then.

Upon explaining the issue over the phone it struck me that maybe I’m not fully comprehending the issue. Mine is a UK car, with the rotary knob in the cabin to adjust beam height. So even though I’ve never touched the rotary knob for s9me reason, capacitor drain suggested, the motor used to activate the lamp is spinning. As the beam isn’t moving I guess this means the motor assembly has disconnected itself from some mechanical linkage.

If I can reconnect it, is it the mechanical linkage that acts as the shut off to stop the motor? Thanks guys.

That's not quite the problem . . .

The problem (probably) is that the capacitors within the control circuit attached to the motor have failed. This usually means they have leaked their contents over the circuit board to which they are attached. Depending on stage of damage, the electrical circuit could be repairable just by replacing the capacitor (i.e. the only problem is that the capacitor is not functioning as intended within the electrical circuit), but the leaked capacitor contents tend to corrode the other elements of the circuit board, even down to the copper tracks that pass electrical signals over the surface of the board.

It sounds like the control circuitry in one of your headlight adjust motors has failed on (so it will run forever), and the other one has failed off (so it won't run at all). Worth checking if the symptoms you see change depending on whether the control knob is turned to the 0, 1, or 2 position.

This is unfortunately a common problem for 90s cars that use this kind of capacitor on circuit boards. You might be alarmed to know that this type of failure can happen in several areas on the NSX - two of the most common areas for it are the climate control unit and the radio.

Kaz and Heineken both have blogs discussing repair of this kind of failure to a radio circuit board - see link below for one that Kaz posted recently:

http://www.nsxcb.co.uk/entry.php?2725-Audio-Head-Unit-(Acura)-service-01

http://www.nsxcb.co.uk/entry.php?2726-Audio-Head-Unit-(Acura)-service-02

[Bonners]

RCGF, many thanks for your input and attaching the links, and apologies for the delay in responding, crazy end to the year!

Finally, I now understand what you chaps mean, both re my specific problem and the general issues related to the NSX electronics. I guess I’ll need to do some reading and see removal of these circuits is even remotely possible for someone like me, or even at the local garage.

Assuming the issue is indeed circuit board related, i don’t suppose buying a new headlamp assembly, as suggested by Honda, is likely to make any difference.

I hope everyone had a merry Christmas, and all the very best for 2023.

[L696ULO]

To stop the motor whirring you can quite easily disconnect the centre console switch.
I have a 1993 NSX, open the centre console compartment, lift the bottom cushioned plate using a small flat head screwdriver at the front middle. That should reveal 4 screws, undo and the compartment will lift out, push the height adjuster button from underneath then undo the centre screw holding the console that should give enough space to disconnect the blue connector to the switch.
Here’s a thread which shows the capacitor circuit board and other info. If the link doesn’t work use the search bar and type headlight height adjuster (the thread is either 2019 or 2019)


http://www.nsxcb.co.uk/showthread.php?15725-UK-spec-pop-up-headlight-height-adjusters (http://www.nsxcb.co.uk/showthread.php?15725-UK-spec-pop-up-headlight-height-adjusters)






http://www.nsxcb.co.uk/showthread.php?15725-UK-spec-pop-up-headlight-height-adjusters

[Nick Graves]

I'd disconnect at the headlamp end and replace the switch with a blank.

Pretend it's JDM Yo!

I think it's the 'needs to function where fitted' thing. And it's not as if you regularly carry a few bags of builders' dust in the boot at night.