280i - More Mirrors, Got 'em apart, now what?

[m2500tvr]

As I'd written a bit ago, the left hand side wing/door rear view mirror of my '85 280i Series "1.5" isn't moving in the vertical plane via the quadrant switch, only in the horizontal. So, I dismantled the mirrors, at least in some large part. It wasn't too difficult. I first spent a fair amount of time inspecting and assessing approaches for taking the mirror apart. Again, the mirrors in question are the black, "free-standing", "plastic-banded", electrically adjustable mirrors mounted on the doors.

What I ended up doing was removing the plastic trim/finishing "ring" at the mirror glass side using a plastic wedge/scraper as a tool to pry into the gap between the out end of the ring and the "band" around the mirror, which released and popped out the ring allowing it to be carefully removed all the way.

With the ring off, and carefully manually moving the mirror glass to its extremes, I was able to access the four 3/16" (4mm?) nuts that secure the mirror/metal mirror blacking plate to the circular plastic frame. Hoping to avoid separating the mirror from the metal backing, I tried removing these nylon insert nuts. The screws they're threaded to aren't captive, but I was still able to remove a couple of these. Removing two, though, wasn't enough to get the glass/backing plate off to access the motor, of course, so I had to separate the these two by breaking the adhesive connection.

Again, having the plastic ring off helped here, too. With this off, I had good access to the joint between the mirror glass and the metal frame it's affixed to via a thin foam pad that is adhesive on both sides. The plastic wedge tool came in handy here, too. I inserted the tool between the metal and foam, not the mirror glass and the foam, and the mirror came free from the backing plate rather easily, with most of the foam adhesive remaining where it was on the back of the mirror glass. Interestingly, only some portion of the left and right edges of the mirror/backing plate were making meaningful adhesive contact.

The mirror and backing plate off, I removed the four screws securing the motor to the metal frame/bracket inside the mirror body/housing. This bracket also was easily removed by carefully prying between the outside edge of the bracket the wrap-around plastic band. This sprung both parts a bit to let them come apart.

I checked the connections, the continuity of some of the wiring, tested the motor for movement, and still the same issue. At this point, I'm not sure how to do more rigorous checks of the switchgear and wiring to confirm the condition of the bits and/or isolate fault, or not. I suspect there's still some chance that the fault is in the quadrant switch or somewhere else in the wiring, but I don't know how to approach further troubleshooting.

This mirror motor is the same thing used by a lot of other cars. I see them often for sale as BMW motors. I may just buy one to try it. I can't figure out how to dismantle the motor any further. I see black plastic tangs securing a white platstic frame that looks like it secures the motor and gears, but in successfully releasing one of these, this isn't just popping everything else apart so I've stopped going after this.

Another bit. The "front" of the mirror, the side opposite the mirror glass, appears to be plastic on the outside, but bonded to an inner metal shell. It does look entirely possible that this outer cover be removed from the plastic wrap-around band, but I haven't been able to finesse this to happen. It appears to "snap" into the band. It would be nifty to remove this 'cuz the metal bit has some rust and removing this part would make treating this (with paint, wax oil, whatever) easier.

I think I'll just buy another motor and give this a try.

Any other suggestions?

- SJ

Edited by m2500tvr on Monday 7th June 18:52

[Grady]

Add a picture or two???

I'd think with a multi-meter and a couple of alligator clip extensions you could work the switch and see if you have power at the motor leads. That should resolve the switch gear vs motor question (and/or apply power to the motor directly). Grady

ETA - That sound way too obvious and I'm sure you have already tried it.

Edited by Grady on Monday 7th June 18:29

[m2500tvr]

Thanks for the reply. Yeah, I've gotta get some pics up. I haven't gotten the picture-taking thing into oridinary process yet, so it feels like a little more work.

Yes, obvious, and I have tried some stuff, but I'm not sure what what I'm testing, what the procedure is, and how to to interpret the results. With my auto-ranging DMM, I have "checked" things at the female connector at/in the door, then at the male metal terminations/connectors at the mirror, which is the last stop before the internals of the the motor. I'm kinda guessing that I might even be able to do some tests on the motor across the female connectors? Could I even bench test the motor with a 12V PS? I'm just not sure exactly which connections need to be made.

- SJ

[Wedg1e]

m2500tvr said:

Thanks for the reply. Yeah, I've gotta get some pics up. I haven't gotten the picture-taking thing into oridinary process yet, so it feels like a little more work.

Yes, obvious, and I have tried some stuff, but I'm not sure what what I'm testing, what the procedure is, and how to to interpret the results. With my auto-ranging DMM, I have "checked" things at the female connector at/in the door, then at the male metal terminations/connectors at the mirror, which is the last stop before the internals of the the motor. I'm kinda guessing that I might even be able to do some tests on the motor across the female connectors? Could I even bench test the motor with a 12V PS? I'm just not sure exactly which connections need to be made.

- SJ

This any help?

http://www.wedgeneering.co.uk/TVR%20390SE%20p7.htm

[m2500tvr]

Yes. This is the documentation you did, right? If so, THANKS! I came across your useful site a long while ago. My problem is that I have some ability and experience to help me understand this schematic, but it's limited. I'm not sure what to do with all/enough of it.

Perhaps the first thing to check is the joystick to make sure it's making and breaking as it should. I don't understand fully how to test the U, D, L, and R iterations, but I'm happy to try and I'm sure just a little coaching would go a long way. I can certainly check the resistances of the solenoid and motor. The solenoid is part of the motor assembly, right? The motor assembly uses one motor, which provides drive to both axes, and the solenoid switches the motor drive between gearing that directs the motor's drive to the different axis movement? One thing that might be useful is that while I hear a clear clicking noise coming from the fully working mirror, I don't from this partially working one. I'm guessing that the solenoid on the partially working motor assembly isn't working for whatever reason. It's not engaging to then engage the gearing to enable the motor to move the mirror on the vertical axis. How do I directly apply power to actuate the solenoid to test it?

To measure the solenoid resistance, I just measure resistance across the brown and the white on the back of the motor assembly, and the black and the blue to measure motor resistance?

Thanks!

- SJ

Edited by m2500tvr on Tuesday 8th June 15:31

[Wedg1e]

m2500tvr said:

Perhaps the first thing to check is the joystick to make sure it's making and breaking as it should. I don't understand fully how to test the U, D, L, and R iterations, but I'm happy to try and I'm sure just a little coaching would go a long way.

OK, meter on a low resistance range (even better if it has a sounder that bleeps if you short the probes together, means you don't need to see the meter while you fiddle with the switch)... and the chart in the bottom left of the circuit diagram will show you which terminal shorts to which for each joystick position. A bleep or something close to zero Ohms is what you're looking for - in practice most moving contacts in switches or relays exhibit some resistance as do the meter leads themselves, so less than say 2 Ohms is good enough.

Terminals 2 and 4 are permanently linked internally so you can disregard 4 to all intents, just see whether 2 goes to wherever it needs to.

m2500tvr said:

I can certainly check the resistances of the solenoid and motor. The solenoid is part of the motor assembly, right? The motor assembly uses one motor, which controls both axes, and the solenoid switches the motor force between the gearing that controls axis movement?

That's about the size of it.

m2500tvr said:

One thing that might be useful is that while I hear a clear clicking noise coming from the fully working mirror, I don't from this partially working one. I'm guessing that the solenoid on the partially working motor assembly isn't working for whatever reason. It's not engaging to then engage the gearing to enable the motor to move the mirror on the vertical axis. How do I directly apply power to actuate the solenoid to test it?

Sounds like a fair assessment. You could simply poke 12v into the brown (-) and white (+) terminals - but do so briefly, and best from a 12v bench supply or a small 12v battery rather than the one on the car. That way if there's an internal short you won't be setting fire to anything

m2500tvr said:

To measure the solenoid resistance, I just measure resistance across the brown and the white on the back of the motor assembly, and the black and the blue to measure motor resistance?

Yep, that's it. The motor will measure about 260-300 Ohms while the solenoid would (if the winding was intact) read a few tens of Ohms, say 60 or so. Without getting too technical, this merely confirms that 'something' is present behind the terminals, it doesn't prove it works. For example, you could measure the correct motor resistance but it might not spin if its bearings had seized. Or the solenoid might measure OK but its armature (moving centre pin) could be rusted up thus unable to move (so no audible click...). Great stuff, electrics

Going back to your earlier comments, even if you can figure out how to break into the thing, there's unlikely to be anything you could do to repair it! I've seen motor units from other cars' mirrors where the white nylon gears have stripped or linkages snapped and you just can't repair that stuff with adhesive... and nobody will sell you spare parts of course. If, by spectacular coincidence it WAS the armature rusted up, you may be able to strip and clean it, but I'd bet on there being a gay paraplegic Libyan President of the USA before you were that lucky

[m2500tvr]

Wedg1e said:

Sounds like a fair assessment. You could simply poke 12v into the brown (-) and white (+) terminals - but do so briefly, and best from a 12v bench supply or a small 12v battery rather than the one on the car. That way if there's an internal short you won't be setting fire to anything

I haven't checked the joystick switch, but I did apply 12v battery power across these terminals. Just three 12v "D" cell batteries in series. Got the motor to run with power across the black/blue. Reversing the polarity reverses the motor's rotational direction. Applying power this way moves the plastic mirror frame in the horizontal plane. Nothing when applying the voltage to the brown/white. And nothing on mixing these connections up with their other connection iterations. Checking resistance in these other ways, there is no connection between them "up and down".

Is that a sufficient test? If the mirror actuator had been working properly would I have at least heard the click of a solenoid when applying power to the white/brown. Dawning on me is that to get vertical movement of the mirror, power gets applied to the motor AND the solenoid at the same time. The solenoid kicks in when the motor is turning, and you get vertical movement. So, it seems to me that power to the white/brown should net me a healthy click, and it's not.

Measuring across the terminals, white/brown and black/blue, I get 60'ish ohms and 35'ish ohms respectively. ??

I've bought a couple of used motors, out of BMWs, to play with.

Thanks.

- SJ

Edited by m2500tvr on Wednesday 9th June 04:50

[m2500tvr]

I bought a pair of mirror motors off of eBay, apparently taken from a BMW of some sort. They have nifty rubber seals on them. The white plastic circular mirror frame bit is a bit different from the one that came out of my 280i, which allows the motors to fit this seal. These BMW motors also have: on one of the motors a diode, on the other a resistor, each connected inline with the upper white/brown terminals. What might these be for??

So, why I didn't do this earlier...? To each of the three motors I now have, I connected the black/blue wires from the car's harness to the white/brown terminals. Danged if a little solenoid started clicking in each of the motors. I also checked for voltage at the black/blue and white/brown wires at the switch. Moving the switch to any position registered 12v on the black/blue, AND 12v registered on the white/brown with the switch in only two opposing positions. BUT, checking for voltage at the wire terminals, 12v on the black/blue, NOTHING on the white/brown.

So, DOH, the motors are probably okay. I am getting voltage out of the switch everywhere I should be, but I'm not getting voltage out to the motors on the white/brown. ???!!! I did some looks around to try to trace the white and brown, but wasn't sure what I should be looking for/what I was looking at.

- SJ

[m2500tvr]

Of all crazy things, I just pulled out my 280i service book copy I bought from the TVRCCNA a zillion years ago to study the wiring diagrams. It turns out that, as far as I can read it, the wiring color codes used by the Tasmin are different from the 390SE. The joystick wiring of all the wiring diagrams in this book appears to go as thus, according to the 280i book:

1. GS/Green Slate 2. N/Brown 3. U/Blue 4. B/Black 5. Doesn't specify, so I'm guessing O/Orange here 6. W/White

Nowhere in/around the harness terminations for this switch do I have a Green/Slate, nor a Blue. I have a Green and a Green/Blue. Are these wired as Green=Green/Slate and Green/Blue as Blue?

The 390SE seems to be wired like this:

1. Green/White 2. Black 3. Green/Blue 4. Brown 5. Orange 6. White

I'm not entirely certain of the orientation of the switch relative to the wiring diagrams. Looking under a magnifying glass I couldn't find any terminal markings on the switch.

So, I'm still not certain of my switch wiring yet, but hooking things up as per the 280i serivce book, still no solenoid engagement on the driver's side/left hand side mirror motor. I didn't check voltage at the switch yet with this wiring configuration.

- SJ

Edited by m2500tvr on Sunday 13th June 01:57

[Wedg1e]

Hazarding a guess, the diode and resistor could be in circuit for interference suppression (?) or current limiting, but possibly the mirrors on the BMW had an electronic controller rather than a simple switch and the resistor'diode ar in there to prevent back-emf damage to the electronics.
Could be the windings were found to be a bit effeminate for the job so they had to limit how much current could flow to prevent large numbers of failures.

The wiring colour differences are probably down the the fact that TVR were obliged to conform to then-current US specification for colour-coding. Euro-standard wiring is probably different, just for the hell of it
In fact I think that way back in the mists of time, brown was earth (just like the earth ) whereas it's most commmonly known as +12v these days.
And don't get me started on Euro-harmonization of 3-phase wiring colours...

[m2500tvr]

I wired the switch as per the TVR service book wiring diagram - or at least in a way I think is the "right" way, 'cuz the book and the car don't quite match up. I am getting voltage across the white and brown wires at the switch as the switch is moved to the position that should engage the solenoid and give vertical plane movement to the motor/mirror. But there's no voltage at the door across the white and brown wires.

This white and brown wire run providing 12v to the solenoid appears to retain the same colors from the switch to the mirror. This isn't the aame for the wires that supply the 12v to the motor. From the switch to the door, these particular wires are Green/Blue and Black/White. Then, from the connector in the door to the final harness bit running from this connector to the mirror, the wire colors map to Black/White to Black and Green/Blue to Blue for the motor, and White and Brown stay the same.

I have to figure out why I'm not getting 12v at the door/mirror on the solenoid-feeding circuit. I've got it coming out of the switch, but not at the door. ??!!

- SJ

[Grady]

Un-connect the wires at both ends and check for continuity of each from one end (switch) of the wire to the other (mirror). Could have gotten crimped/broken by the window operator. Grady

[m2500tvr]

Grady said:

Un-connect the wires at both ends and check for continuity of each from one end (switch) of the wire to the other (mirror). Could have gotten crimped/broken by the window operator. Grady

Thanks, Grady. I know I'm getting power to the motor and solenoid of the right hand mirror, and power to the motor but not the solenoid of the left hand mirror. Corroborated by DVM and mirror/solenoid behaviors. I'm not sure how to trace the entire length and every connection point of the white and brown wires that provide voltage for the solenoid operations.

[Grady]

I bought a 1984 BMW 3 Series mirror from ebay - It has the same motor with the same colored wires but a different mounting bracket - doesn't have the 4 tiny screws that hold the mirror plate to the motor. Didn't work - I now think it had a bad motor based on the resistance readings - also had the extra resistor.

I also bought a 1979 BMW e21 320i mirror. Same motor, same mounting and same wiring. Works but with only one motor connected the side-to-side/up-down function is reversed. If you rotate the motor 90 degrees it works but doesn't fit the mounting bracket.

The mirror came off very cleanly when I stuck a putty knife between the glass and the plate - I tried to press the blade toward the plate side to avoid gouging the mirror.

Edited by Grady on Monday 23 May 14:22

[Grady]

I found what appears to be the same motor new for the same money as a complete but 30 year older model. I just ordered one. Grady

http://www.rmeuropean.com/search.aspx?keyword=51-16-1-394-107

[m2500tvr]

Sorry for not getting a response to this thread. I did buy a couple of motors myself. They are drop-ins for the original motors with the minor difference in having a different white ring part (I'm doing this from a slightly distant recollection) that accepts a rubber seal to protect the motor. It's a nice feature. I stopped with the replacement motors because finally testing thoroughly enough I found that my original motors worked fine, I've got a fracking issue with the wiring somewhere. Woulda been easier to replace the motors. I've found it VERY challenging to trace all the connections between the quadrant switch and the mirror. The switch and motor seem to be okay. Just can't find the complete patch between them to see where things aren't connecting!

I'd be happy to share pictures and part numbers (which I think are exactly the same as the numbers of the original motors) of the motors I got.

[Grady]

I'm confused how up/down became right/left. The terminals are clearly marked (unless it's b/c now I only have one mirror installed). Be interesting to see what happens when the "new" one arrives.

Edited by Grady on Wednesday 25th May 15:36

[Grady]

I just received my new motor (made in 4/08). Looks the same except it has the resistor (I guess) between white and brown.

What would you recommend, leaving it in or cutting it out???

Edited by Grady on Wednesday 25th May 21:14

[m2500tvr]

yeah, the ones i got also had either a resistor or a diode (iirc) strung between whatever (I don't remember at the moment). connecting these motors up, and testing operation, these extra bits didn't seem to make a difference. i suggest leaving them in place until/unless counterindicated

[Grady]

I left the resistor in and it works fine.

The only wierd thing is the up/down and side/side functions are now reversed on both mirrors. I did not TOUCH any of the switch gear and the wires are color for color.

I'll adjust to it. Grady