How to test electric mirror glass?

[dErZ]

I took my passenger side glass out as it hasnt worked in years and wanted to get it sorted before the ice age arrives. The right one works so checked the fuses and there only appears to be one for both sides. There isnt actually a picture denoting heated mirrors only 2 symbols for heated screens both of which the fuses are fine. So with a volt meter what do i need to set it to to find out if its fubared? and what should i see as a result or failure?

 

[Slimy]

My heated mirrors operate with the rear screen demister, but only when the engine is running. Easiest way is to set it to 20V and measure if there is 12 volts (ish) across the wing mirror terminals.

I'd put at least tuppence on the fact that it's the glass element itself that's broken, you'll get 12 volts across the terminals and a replacement glass will sort it.

 

[rf860]

I thought the heated mirrors were controlled by the knob that folds then in and adjusts the mirror glass?

 

[Slimy]

I thought the heated mirrors were controlled by the knob that folds then in and adjusts the mirror glass?

Quite possibly, but the voltage at the glass should still be the same.

 

[dErZ]

So with the glass off and set to 20k(2 to the right in the picture) I get a reading of 0.65 ??

 

[mick-fr]

So with the glass off and set to 20k(2 to the right in the picture) I get a reading of 0.65 ??

You want to use this setting...

 

[Nath.]

Switch the meter over to the setting with the musical note (one to the left of where it is in your pic) then put one probe onto each connector of the removed mirror glass. If the meter beeps at you the element should work when voltage is applied.

Switch the meter to the "up to 20 volts DC setting" (10 to the right of where it is in your pic) and you should get a reading of about 12 on the wiring for that mirror. If I remember correctly they come on with the heated rear screen switch on a MK4 Ibiza.

 

[Nath.]

You want to use this setting...

That setting is for measuring up to 20 volts DC, not resistance. The OP sounds like he is attempting to check the resistance or continuity of the heating element.

 

[dErZ]

Cheers chaps, so with the musical note it reads .614 (remember the mirror is off the car) if i touch the 2 probes together it beeps. What does that say about the glass? I will test the the wiring incar 2moro.

 

[mick-fr]

That setting is for measuring up to 20 volts DC, not resistance. The OP sounds like he is attempting to check the resistance or continuity of the heating element.

My bad, thought he was checking to make sure it had a feed. I did illustrate half your answer though

 

[dErZ]

So how do I measure the resistance and what should it read?

 

[Slimy]

OK, if you're testing the resistance of the mirror glass, the fact that it didn't beep when you tested it on the musical note means that it has failed. Ignore the reading.

 

[dErZ]

Cheers Slimy and everyone else for their input. New mirror to be ordered 2moro.

 

[Nath.]

OK, if you're testing the resistance of the mirror glass, the fact that it didn't beep when you tested it on the musical note means that it has failed. Ignore the reading.

Crrect.

You should check for 12 volts DC supply when the mirrors are switched on and then buy a new glass with heater. Halfords will be cheaper than the stealers I think

 

[luna fr]

Do all FR s have heated mirrors mines an 04 and doesn't seem to have them.

 

[Slimy]

Do all FR s have heated mirrors mines an 04 and doesn't seem to have them.

I've never been able to understand what kit goes with what model, as various people with apparently the same car have different kit. I would expect an FR to be reasonably high specced though, isn't it the top diesel in the range?

What you could do is go to the drivers mirror, and wind it all the way to the left. That should bring the outside edge as far out as possible. Pull it a bit further and get a torch in there, see if you can see a couple of wires inside the casing. If you can, it means you have heated glass but they're not working. Be careful though, use your fingers rather than a screwdriver otherwise you might crack the glass.