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I wonder if it's acting as a spring, designed to move the locking bar into the slot in the steering column. If you park, and lock the column, at some non-straight angle of the steering wheel, presumably the locking pin cannot go into the slot in the steering column, as the two don't line up. If someone attempt to steal car and turns the wheel, there has to be some kind of spring tp push the locking bar into the steering column, even if there's no power anywhere. Perhaps that's what this is for, and why there's a magnet. That alloy bit seems to have a large amount of backlash play in it, which would fit this theory.
Indeed, I think you've hit the nail on the head. That's exactly how I understood it when I removed mine. Seems to be how it 'springs' up to lock the wheel when not aligned when it enters the 'locked' mode.
 

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For that reason we have a spring that preloads locking pin, and when it hits a axle "in the wrong spot"and someone turns the wheel then pushes forward and lockes the axle...
 

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Whichever method is used to spring the bar in, mechanical or magnetic, they're both going to put an extra load on the tin can motor if you lock the car with the steering wheel off-central. That motor overheats in my opinion, see the pic of the blued laminations on the armature. I've never seen that on motors of this size type before, and believe me, some of the slot-car motors I used to use would draw currents of 10+ Amps at 12V under acceleration - they were wild. And they got really, really hot, hot enough to melt the bell-end of this particular motor I expect. These motors drew so much power that you needed a car battery to power each car taking part in races, forget those old scalextric transformers, nothing like up to the job. But the armatures never went blue like that! No doubt helped by having decent air circulation, of which there's not a lot in this design.

So parking with the steering wheel staight ahead should reduce load on the poor motor, and maybe reduce wear & tear on it's commutator as a result, so helping to keep the torque output reasonably high.
 

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I almost got stranded today again, being that despite removing the module, I couldn't see any parts that looked like they needed attention so I had fitted the module back minus the locking pin. However the motor almost gave up and despite about 15 attempts didn't seem to want to come back to life. I also found that despite removing the locking pin the module will still not release from the steering column unless in the unlock position. I guess there is another nib that is still engaging. I will have to remove that as well. Luckily powering the car on, in 'ignition only' mode (holding the power-up button - without touching the brake) seemed to jolt it back to life - not sure why this worked, perhaps the software routine is different to the regular power on sequence.

Meantime I've ordered this module from USA https://www.ebay.co.uk/itm/New-OEM-Cadillac-ATS-CTS-SRX-Steering-Column-Module-2014-GM-P-N-23203935/183977717123?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649 and will try find something to help keep my old module going until it arrives (maybe some light oil or contact cleaner in the motor?)
 

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Done some further investigation... It appears the fault may be electrical rather than mechanical. Applying as little as 3v to the motor seems to reliably operate the latch in both directions (see video here https://photos.app.goo.gl/BiAXPT2AQZAUC4Zf7).
I thought perhaps it's a faulty relay like @wolfer11 - but my board looks perfect - no obvious signs of failure. I'm starting to wish I ordered a module from a UK supplier now, as doesn't seem likely I can do anything to sort this one, and not sure I can wait for the one from USA. Unless someone with PCB/component experience can identify anything in these photos?

PCB1.jpg PCB2.jpg
 

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Those board pics look pretty ok to me. No obvious signs of possible dry joint that may be arcing that I can see.

It's not a good idea to dose these tin can motors with oil. You want the commutator to be clean & dry, and ABSOLUTELY NOT oily.

I'd be inclined to try & clean the commutator by taking motor out, and squirting a load of Lighter Fuel (nothing else) into the bell-end, to try & flush any crud/oil/carbon dust off the commutator. I wouldn't risk contact-cleaner stuff, as that can leave a residue. Turn the rotor by hand as you do this, will get the brushes wiping the copper a bit, may help. Leave it 1/2 an hour for that to evaporate out completely. Then put a TINY drop of oil on the commutator-end bell-end bearing, and put a reasonable drop at the metal case end. That end is well away from commutator so little risk of oil on the commutator. The oil should soak into the tiny oilite bearings, so you really only want a very small amount indeed.

I have wondered how they detect whether the bar has moved or not, i.e. how do they know it's failed or not? I have a nasty feeling they must be detecting the motor getting stalled at the limit of travel, and this would cause the motor winding current to rise suddenly. If they measure the motor current, that would be a very crude & nasty, but cheap & effective way of detecting end-of-travel. If they do this, then disconnecting the motor from the bar might have interesting results - I'd expect the car to detect a failure to get to the end stops after the right time interval. Do let us know what happens! We're intrigued!!
 

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I have wondered how they detect whether the bar has moved or not, i.e. how do they know it's failed or not? I have a nasty feeling they must be detecting the motor getting stalled at the limit of travel, and this would cause the motor winding current to rise suddenly. If they measure the motor current, that would be a very crude & nasty, but cheap & effective way of detecting end-of-travel. If they do this, then disconnecting the motor from the bar might have interesting results - I'd expect the car to detect a failure to get to the end stops after the right time interval. Do let us know what happens! We're intrigued!!
Just tried the unit in the car with the locking nib completely removed... The unit remembered it was in an unlocked position as it made no attempt to unlock. On locking however, it made the regular locking chirp twice in immediate succession. So to me it's still inconclusive as the motor did not run-on even though there was no resistance whatsoever. It ran for the same 1/2 second it would have ordinarily, only it somehow knows it's not engaged the nib and makes a 2nd attempt for another 1/2 second. But that's it. I'm wondering if the magnet interacts with a chip in it's proximity?
 

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Hmm, Modo, what happens if you lock the car so the motor runs, but you manually move the nib as if the motor had operated it? I'm assuming you remove the motor from casing, but everything else is in place. If that stops the 2nd locking chirp then that's pretty conclusive of a hall-effect sensor somewhere close detecting the movement of the magnet. TBH I was amazed to NOT find any kind of limit-switch on the nib & moving bits.
 

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Meantime I've ordered this module from USA https://www.ebay.co.uk/itm/New-OEM-Cadillac-ATS-CTS-SRX-Steering-Column-Module-2014-GM-P-N-23203935/183977717123?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649 and will try find something to help keep my old module going until it arrives (maybe some light oil or contact cleaner in the motor?)
That is the source for the one I have and has the same tension pin locked unit. It turned up very quickly from the US.
A post from elsewhere would suggest that these modules are coded but at least it will give spare parts or a new unit if the controlling chip is swapped.
Hopefully though, @modo has plugged in a non coded board and it wasn't rejected so I need to get off my Rse and plug mine in to try it out.


I agree with @HandyAndy though and cannot see a Hall Effect sensor close by on the board. There are few active components anywhere near. Oddly I also cannot see anything that the current would be sensed with as it would need some sort of shunt resistor in the motor supplies and the only component in the line would seem to be the controlling MOSFET with a heatsink soldered to the board.
 

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Done some further investigation... It appears the fault may be electrical rather than mechanical. Applying as little as 3v to the motor seems to reliably operate the latch in both directions (see video here
I thought perhaps it's a faulty relay like @wolfer11 - but my board looks perfect - no obvious signs of failure. I'm starting to wish I ordered a module from a UK supplier now, as doesn't seem likely I can do anything to sort this one, and not sure I can wait for the one from USA. Unless someone with PCB/component experience can identify anything in these photos?

View attachment 125062 View attachment 125063
Did you test the relay??
The white box like component???
The motor must be powered by the relay.
125122
 

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Thanks @Russ for confirming it is the same (I got the part number from an earlier post) hope mine does arrive quickly as I got stranded for 10 mins again today (cleaning/oiling of motor seems to have made no difference). @Jaime Branco I didn't test the relay as I wasn't sure which pins to test (have now found schematic online - but I'm no expert of board components and didn't want to fry any controller chips - is it pins 3-2 on the relay that I'd power? https://www.mouser.co.uk/datasheet/2/212/EX1_ EX2 relay 2012-1173029.pdf) - also the board is coated with what must be a sealant/waterproofing layer and I'm unsure how to deal with that? Truth is, once my replacement module arrives (assuming it works - as there is this talk of them being coded which I'm hoping is false) I'll be far happier to play with it. At the moment I'm relying on the current modules occasional functioning to use the car!
 

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@modo if you take out the 5A fuse in the engine compartment you get a error but the car works normal.... This only works if the steering is not locked. You have to power down the car with the drivers door open for the car not lock the steering wheel than you take out the 5A fuse.
 

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So many replies in this thread concerning this crappy steering lock. It certainly wasn't designed by the group of people who built the Voltec drive unit that's for sure and a quick Google finds it having being taken directly from a parts bin as used on other GM models.
This module has proven to have been the bane of many peoples lives over in the US on a number of high end cars.
The module @modo and I have purchased has a higher part number than those installed and is in fact on a recent invoice posted in this thread with another earlier part number actually installed so it will be interesting to take a look inside for any improvements.
 

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Hi, I'm new here but found the forum and thread because my beloved '15reg Ampera has bricked itself on my front drive with the steering lock issue. I suspect this was due to a < 12V supply from the original GM battery in the cold, but replacement of this with a new AGM one has not breathed new life in to the lock motor which seems totally dead.
I've been through the F2 / F8 fuse replacement therapy a few dozen times without luck.
I'm not sure whether it locked itself before it developed the fault, but the old-fashioned steering column lock is now engaged due to my wang-ing the thing around to hopefully release the lock.
Getting the car off the drive at 90º to a busy London red route with the steering lock on will be no end of grief, let alone the weeks and hundreds of pounds lost at the dealers.

Can anyone advise:
A) how I can free the old-school steering lock;
B) check the status of the electronic module lock;
C) and whether a viable off-the-shelf replacement module can be refitted without any programming?

I've followed the thread up to now, but I'm unsure as to the points above. Any help you could provide would be gratefully received - tearing my hair out here!
Thanks.
 

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I'm still waiting for my eBay module to arrive from USA so can't confirm if the module will be a 'drop in' replacement. Bearing in mind there are shear bolts which are a real pain to remove (drop-in isn't quite the right term unless your handy with the right tools).

In the meantime my module is mostly still rumbling weakly on. I've found on occasion when it gives up completely - to get it rejuvenated - it seems to help to 1) open drivers door 2) with door open, power the car on without drive (ie ignition only, so hold the power button down for 5 seconds WITHOUT touching the brake pedal until it powers up) 3) turn off with drivers door open. This sequence forces the motor to attempt to move in both lock/unlock directions in quick succession and generally works for me.
If you hear the lock 'unlock' after ignition, DO NOT TURN OFF THE CAR, simply depress brake pedal and press power button again - which switches the car into 'drive allowed' mode, and your off and away. I'd then disconnect the wiring harness from the lock module so it can't mechanically lock your steering again - but ideally get those bolts off asap.
 

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@1608Chris sorry to hear about your problem. This is a well known fault both in the UK and US on cars that supplied the steering lock from their parts bin and should be subject to a recall but never was by GM.

I don't know how useful with tools you are but a grinder will be needed to remove the shear bolts (the head shears off after tightening). Maybe use a cutting disk to cut a slot in the shaft of the bolt and will take a look myself.

As this problem seems to be getting worse I will take a look at mine this weekend and try plugging in my spare sourced from the US.
It really is stupid that these Mickey Mouse steering lock servo's are built with Scalextric type motors sourced from China and without end stop limit switches.

My guess is that you will find a burned track on the PCB as @modo did if the lock doesn't revive with a fuse replacement.
 

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Modo / Russ,

Thanks for your helpful replies. I agree wholeheartedly that this seems like a recall matter to me. Hopefully with everyone's pooled knowledge we can develop a good DIY fix. I'm handy enough and have both a Dremel and angle grinder to get at the shear bolts, but I'm no engineer or electronics whizz so I'll stick to what I can remove & replace. I'm just hoping I can free up the steering using the advice from Modo - I didn't know about that non-drive start-up mode!

I would say to anyone reading this wondering whether to address this problem at first symptoms - do so. Don't wait until total failure & Replace that GM battery.
 
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