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Brit01 |
Posted: Thu Jan 13, 2011 5:56 pm Post subject: |
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I was probing around with my DMM last week.
I found that the lines with the mat grey material on them seems to be the conductive material.
I was getting 12 volts on these areas on the right hand side.
Where this has rubbed off leaving the dirty yellow underneath film I was getting no reading.
So I guess there is no way of fixing this.
Next week I'm getting UV film put on the windows anyway so it's all going to be covered up. |
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Admin |
Posted: Fri Nov 12, 2010 6:50 pm Post subject: |
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Oggie wrote: |
Probing with a multi meter will not find the breaks, the element is one big cuircit. Weather it has a break the meter will still bleep unless all the elements are broken. |
You can probe fore resistance though, which will jump after the break.
All the best
Keith |
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Guest |
Posted: Fri Nov 12, 2010 11:28 am Post subject: |
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I bodged my faulty demister (only 3 lines in middle working) by running a really soft pencil over the whole element, just dont wipe the window after... |
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Oggie |
Posted: Wed Nov 10, 2010 8:48 pm Post subject: |
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Admin wrote: |
Brit01 wrote: |
Got to get my DMM out and do some probing around.
Only the middle element heats up on my window. |
If one element is heating up then looks like power is getting to the screen. At a guess the elements in the rear screen are damaged. You can get small pots of conductive paint to repair heated rear screen (difficult bit is probing with the multi meter to find the breaks).
All the best
Keith |
Probing with a multi meter will not find the breaks, the element is one big cuircit. Weather it has a break the meter will still bleep unless all the elements are broken. |
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BigAl |
Posted: Tue Nov 09, 2010 10:36 pm Post subject: |
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lol
guess what, it has stopped working again |
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Brit01 |
Posted: Mon Nov 08, 2010 1:34 pm Post subject: |
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What a stroke of luck!
Had a rainy day the other day and the whole car was like a sauna.
Could only see through the windscreen due to the heater there.
Parking in my rented place was a little difficult between 2 Hilux pick ups with about 18 inches either side! |
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BigAl |
Posted: Tue Oct 26, 2010 10:36 pm Post subject: |
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it started working 2 months ago lol |
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Admin |
Posted: Fri Jun 04, 2010 3:57 pm Post subject: |
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Brit01 wrote: |
Got to get my DMM out and do some probing around.
Only the middle element heats up on my window. |
If one element is heating up then looks like power is getting to the screen. At a guess the elements in the rear screen are damaged. You can get small pots of conductive paint to repair heated rear screen (difficult bit is probing with the multi meter to find the breaks).
All the best
Keith |
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BigAl |
Posted: Mon May 24, 2010 9:02 pm Post subject: |
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Hi Brit,
no, i gave up, didn't make sence and don't want wires all over the place. |
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Brit01 |
Posted: Mon May 24, 2010 12:04 pm Post subject: |
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Hi,
Any update on your heater issue?
I have the same issue but haven't looked into it yet.
Got to get my DMM out and do some probing around.
Only the middle element heats up on my window. |
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BigAl |
Posted: Thu Jan 14, 2010 4:58 pm Post subject: |
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When The weather gets a bit better and i can move it nearer i will investigate further. I have taken a quick look and tried to eliminate the easiest thing first.
Checking the + means taking out the fuse box and checking the back of it and checking the connections on the switch... |
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lee16v |
Posted: Thu Jan 14, 2010 1:52 pm Post subject: |
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I think Iain is trying to get a message to you Al! |
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john 33_16v |
Posted: Thu Jan 14, 2010 12:23 pm Post subject: |
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You could run a good 12v supply from the battery or a spare battery direct to the element to eliminate that.
John |
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Oggie |
Posted: Thu Jan 14, 2010 12:20 pm Post subject: |
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melted connector block!!!!!!. |
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BigAl |
Posted: Thu Jan 14, 2010 10:35 am Post subject: |
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Anyone?
If i have eliminated the earth, that leaves the + part of the circuit or the element? |
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BigAl |
Posted: Tue Jan 12, 2010 9:39 pm Post subject: |
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well, the ones i took off were on the body. I checked the earth which is a 10mm bolt on the tail gate near the earth cable connection to the RWH and used a good earth from the boot light, made no difference.
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eagle3 |
Posted: Fri Jan 08, 2010 8:01 am Post subject: |
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AhA! |
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BigAl |
Posted: Thu Jan 07, 2010 6:12 pm Post subject: |
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Thanks eagle,
Come to think of it a while back i took those rubber things off and turned them around, the earth could have come off |
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eagle3 |
Posted: Thu Jan 07, 2010 12:59 pm Post subject: |
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BigAl |
Posted: Thu Jan 07, 2010 11:37 am Post subject: |
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Thanks guys, eagle you are correct, i got -14v at first, then swapped so the + was on the left side.
When i can move my car i will investigate further. I will connect teh + to the demister and the other side to an earth on the body. Where is the earthe from the demister btw? |
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eagle3 |
Posted: Tue Jan 05, 2010 5:57 pm Post subject: |
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Isn't the left spade +(12v/14v) and the right spade - (bodywork)? |
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Ben_nz |
Posted: Tue Jan 05, 2010 9:23 am Post subject: |
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Oops, that was me above. I wasn't logged in and now I can't go back and edit out all my typos. |
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Guest |
Posted: Tue Jan 05, 2010 9:21 am Post subject: |
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I agree, there's a poor connection somewhere. You measure voltage on the wires when they're disconnected, but this is voltage is all bark and no bite. Due to a (big surprise in an old Alfa) poor connection somewhere creating high resistance, the voltage is unable to drive enough current through the circuit to get your demister very warm.
The poor connection might be a 'bad earth' - one of the two wires you've mentioned earths the demister to the metal of the hatch, and the connection to the hatch could've corroded. To work out which is the earth wire (assuming you can't just trace it and see), unplug both wires, turn the demister switch on and use the DMM to measure between wire 1 and any exposed/unpainted bit of metal on the car body, then between wire 2 and the exposed bit of metal. The wire where you measure 0V is the earth for the demister, and the wire where you measure 12~14V is the one supplying the demister with power.
Turn the demister switch off, change the DMM to the ohms / resistance setting, and measure between the earth wire and your exposed bit of metal. You should measure only a couple of ohms (say between 0 and 2 ohms). If you measure much more than this, you've got a bad earth. Trace wire to where it attaches to the hatch, undo the connection and clean it. After you've confirmed with the DMM that the earth's good, set the DMM back to the volts setting. If there are no problems with your demister circuit, you should measure most of the battery voltage being dropped across the demister (i.e. 12V or more between the spade connectors when the wires are connected and the switch is on).
If you don't have a bad earth, your poor connection is somewhere else e.g. the wiring loom connector plug that Oggie is betting one pound on! |
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BigAl |
Posted: Mon Jan 04, 2010 9:55 pm Post subject: |
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lol place bets now
I'll do my best, i hate electrics.
Cheers |
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Oggie |
Posted: Mon Jan 04, 2010 8:35 pm Post subject: |
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You know what Im gonna say so, Its just a positive cable to a fuse then to the connector then off to the switch, an earth on the boot lid, the wiring is the same as an s2 , you may have different colour cable and switch and connector but the principle is still the same, put aside your ddm for now and look for a bad connector al, its in there somewhere I would lay a whole £1 bet on it |
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