1984 mirror motor / solenoid help please

[Targa_whaletail]

Hi all,

I've a 1984 Carrera 3.2 Targa with the standard flag door mirrors. I've had long standing vibration in these (like enough at high speed to be dangerous in terms of visibility), and the previous owner had stuck convex mirror glass over the original glass.

So the extra glass came off the driver side, but still some vibration. Then the electric joystick control seemed to stop working. So the mechanic kindly stripped everything down, and I provided a new joystick switch, a new window selector switch (under dash), and some new glass for the driver side - part 91173103508.

So then it turns out this did not resolve the issue. We have both electric mirrors apart. The motor (black and blue wires) turns in either direction (change polarity connected) and the "fishing line" moves the black mirror backing. I used a small 9V battery to check.

However, the solenoid (also called clutch elsewhere I see) does not seem to be actuating. This has a 1N4004 diode across it.

The actual motor housings are no longer available...

Aside: Bentley seems to be plain wrong in distinguishing 1984-1985 and 1986-1989 mirror electrical schematics. I really think they have them partially mixed.

My questions:
- What is the best way to test the solenoid?
- Could the diode be gone?
- Are replacement solenoids available?
- If I can't get or prove the solenoids are working, what do I do? Can the 1986-89 parts be fitted? looks really expensive. Might need to remove any shake though..?
- Is 91173103508 actually a heated mirror? Because I seem to have the heated mirror connections

Pic of inside below.

Thanks!

[Targa_whaletail]

Thanks for the wiring diagram under separate cover - 86 911 Targa / Gary.

This confirms that Bentley is wrong...

So, some more research suggests that it's the spring in the solenoid that has failed. Found a Rennlist page that suggests using a cutdown spring from a ballpoint pen!

[Targa_whaletail]

A quick update:

Using a 12V PSU - with positive to white on the solenoid, negative to yellow/brown, one solenoid worked (i.e., from one of the mirrors) and the other didn't.

I temporarily disconnected the diode, the solenoid started to work! So have ordered another 1N4004 diode.

Trying to locate new springs for each solenoid as they are a bit lazy. Spring is needed to keep solenoid extended. When energised, they pull inwards to change the direction.

Think the *may* be Compression Spring (3178)

Inches, Lbs mm, N
Spring Type Compression Spring Compression Spring
Stock No. 3178 3178
Outside Dia 0.125 3.18
Free Length 0.375 9.53
Wire Diameter 0.018 0.46
No of Coils 11.5 11.5
Max Solid Length 0.25 6.46
Rate 12.97 2.27
Max Safe Load 1.57 6.96

[Targa_whaletail]

Uh oh.

If only it had been that easy...

The reason the diode failed is a short in the wiring loom through the driver side door.

Does this mean the door needs to come off (e.g., body shop?)

[Targa_whaletail]

Well two steps forward, one step back...

The body shop removed the door, and the wiring was replaced. They also welded a new part on so the "click" is finally gone (I already had the door hinge reinforcement kit installed).

The mirrors now adjust up / down / left right perfectly - both sides!

All is not well though...

There is still a little up and down movement in the mirror glass at speed. However, it's not too bad, and I'll see if I can put up with it. The only alternative seems to be to install relays, and the later circular style double motors and new glass (a rather costly exercise!).

The second and bigger issue is that pulling the defog knob pops the 25a fuse in the front. This also knocks out the fresh air blower. I realised several fuses later that they must have reconnected the heated mirrors... but that there is a short somewhere

I also used the rear wiper (the motor is only a year old) and turned off before the end of cycle. This no longer works. A 15a fuse at the rear had popped.

It's possible this is an unrelated fault (grr) and the motor has stalled forever. Or maybe this fuse is shared with the rear defog, and a fault on the heated mirrors is related...

As an aside, I think the defog button is supposed to work as follows:
1. Pull out / not twisted: defog some lines on rear window - can be left on [also defogs front windshield function which I don't have. Heated mirrors
2. Pull out / twisted to right: defog all lines rear window - at high power for 10 mins or so as defined by the relay/timer box near rear fuses. Heated mirrors
3. Pushed in / twisted to right: presumably the same as above for me as I don't have a heated front windshield. Heated mirrors