Rear headlight level control sensor/rod assembly

Morning all,

So I’ve sorted the front headlight levelling arm ready for an MOT retest tomorrow, but the tester added an advisory to say the rear sensor was ‘seized’

Having been under the rear of the car yesterday, I’m struggling to see how he could determine this has seized, so looking for a view please.

Part 10 in the diagram below, the linkage, is rusty. However, everything is present and correct and attached where it should be.

On the basis that these parts move up and down with the suspension, I’m struggling to see how anything could be ‘seized’

Surely if any part of this was seized, something would snap as soon as you hit a bump in the road?…. Am I missing something?

I don’t want to replace parts unnecessarily.

He might have grabbed part #9 and tried to swivel it back and forth. It's a ball and socket design, it should swivel.

javis20 said:

He might have grabbed part #9 and tried to swivel it back and forth. It's a ball and socket design, it should swivel.

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Yes, possibly.

Is my thinking correct though, surely if this was seized it would snap at the first big bump in the road ?

I have to agree. The ball has to turn inside the socket to function. It doesn't need to swivel to function. Possibly it's seized with respect to swiveling back and forth. Either way it's functioning, otherwise it would break.

Do the headlights respond when you accelerate. Dip down.
Unless the tester takes it on the road i can't see how he could pass or fail them.

flybobbie said:

Do the headlights respond when you accelerate. Dip down.
Unless the tester takes it on the road i can't see how he could pass or fail them.

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At this point, I’m not sure… I hardly ever drive the car at night.

He failed the car, correctly, as the front arm was broken (basically ‘ovalled’ and wouldn’t stay attached) so the headlight aim was incorrect. I’ve sorted that, and he’s going to reset the headlight aim for me tomorrow before re-testing.

The rear he’s put an advisory of ‘seized’… I’ve cleaned it up and the Rod does move on its attachment points, but you can’t possibly test if it’s working without putting something heavy in the boot!

My point though, was that it can’t surely be physically ‘seized’ because as soon as the suspension compressed the plastic arm would snap!

Just to confirm, I did give this a bit of a clean up and spoke with the MOT tester to explain what it does and how it works, now happily removed as an advisory and a clean MOT pass today