Rear Screen defogger
09-09-2002, 09:10 AM
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Rear Screen defogger
'88 S4 Euro - My rear screen defogger appears not to be working - the switch pushes in and turns and the light comes on - the side mirrors defog quickly but the rear screen is not working - any ideas, guys?
Cecked fuse and swapped relay - no difference - where do the screen wires connect - in trunk or in head lining?
All help appreciated as usual.....
Thanks......Andy
<img src="confused.gif" border="0">
Cecked fuse and swapped relay - no difference - where do the screen wires connect - in trunk or in head lining?
All help appreciated as usual.....
Thanks......Andy
<img src="confused.gif" border="0">
09-09-2002, 09:28 AM
#2
Drifting
Hi Andy
The connections for the rear window defroster are underneath the trim peices on each side of the rear window. These peices are clipped into place. Hope this helps.
The connections for the rear window defroster are underneath the trim peices on each side of the rear window. These peices are clipped into place. Hope this helps.
09-09-2002, 10:14 AM
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Jack - thanks
I've had these off and looking from the tail in I have a pair of red wires on LHS and pair of black on RHS - I cannot get any voltage here - any ideas as to how I can test / where do the red and black wires come from / go to?
Thanks for prompt response........Andy
<img src="confused.gif" border="0">
I've had these off and looking from the tail in I have a pair of red wires on LHS and pair of black on RHS - I cannot get any voltage here - any ideas as to how I can test / where do the red and black wires come from / go to?
Thanks for prompt response........Andy
<img src="confused.gif" border="0">
09-09-2002, 10:30 AM
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Mine sometimes works (depending on the level of brutality applied) and the problem is the switch in the pod which needs replaced. Luckily it's easy to get at from the front.
DaveW
DaveW
09-09-2002, 01:05 PM
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Dave - thanks for reply
I may be missing something entirely here - when I push my switch in the light comes on but the switch does not click - it is (and has always been) a soft push in and out to same position - is this how yours is or does your one actually click in and out? (- and is this where you have to be brutal to get yours to stay in?).
Perplexed.........Andy
<img src="confused.gif" border="0">
I may be missing something entirely here - when I push my switch in the light comes on but the switch does not click - it is (and has always been) a soft push in and out to same position - is this how yours is or does your one actually click in and out? (- and is this where you have to be brutal to get yours to stay in?).
Perplexed.........Andy
<img src="confused.gif" border="0">
09-09-2002, 03:06 PM
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Andy,
there are two modes of operation for this switch: If you push it straight in the screen heater stays on for about 10 mins then cuts out. This is a soft push with no 'click" and the button stays at the same level before and after the push. If you turn the **** 45 degrees clockwise then the heater will stay on continously (as long as the ignition is on) and the button will stay in the 45 degree position until returned manually.
On my Auto all is well but on the 5spd the 'push' action doesn't work and the 'turn' action sometimes works. It's on the list...
DaveW
there are two modes of operation for this switch: If you push it straight in the screen heater stays on for about 10 mins then cuts out. This is a soft push with no 'click" and the button stays at the same level before and after the push. If you turn the **** 45 degrees clockwise then the heater will stay on continously (as long as the ignition is on) and the button will stay in the 45 degree position until returned manually.
On my Auto all is well but on the 5spd the 'push' action doesn't work and the 'turn' action sometimes works. It's on the list...
DaveW
09-09-2002, 06:19 PM
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Dave - thanks
My switch does the right things then - the relays appear to do the right thing also so I must be have a shot connection somewhere......
On another note - have you tried Douglas Valley Breakers for a new switch - they are up north (Cheshire I think)01257 472866, quite reasonably priced and seem to have a reasonable range of 928 stuff?
Thanks again.............Andy
My switch does the right things then - the relays appear to do the right thing also so I must be have a shot connection somewhere......
On another note - have you tried Douglas Valley Breakers for a new switch - they are up north (Cheshire I think)01257 472866, quite reasonably priced and seem to have a reasonable range of 928 stuff?
Thanks again.............Andy
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09-14-2002, 09:02 AM
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OK - with lots of help from all, this is now fixed!
Red white and red black wires from "T" coded socket on front lower RHS of fuse panel run along side the outer sill of passenger footwell up into the rear three quarter panel directly to the left of the passenger seat. Under here they connect to another loom which is comprised of one brown wire and 6 black bonded together to form a flat "strap". This runs up the B post across the top of the rear part of the head lining where it then exits over the hinge to the rear hatch in a black plastic shoe and under the head lining panel that runs the full width of the top of the hatch (which also holds the centre rear interior light. There is a connector under here which distributes the power to the light and the rear window heater.
My problem was no power at the rear window heater or the light unit - tested at the fuse panel with a simple bulb tester (For testing purposes - switch the ignition on and turn the rear heater switch to position one only. Test bulb on and then test bulb off).
Mine tested OK so moved on to the connector under the rear 3/4 panel - undo the two upper screws holding panel to roof - one has a coat hanger plastic **** on it. Gently pull the door trim away down the door frame. Take out the rear seat lower squab (this looks cheap and nasty when it is removed - a bit of foam and lots of glue!) - you can then see a small trim screw holding the trim panel which the rear lap belt come through - remove this and gently deform the panel to slip out a metal U clip half way up (holds this panel to 3/4 one). Underneath the area where the screw was you will see another small screw holding the 3/4 panel - undo this. My car has a speaker mounted in the 3/4 panel - it does not look standard (the stereo is not) I took this off also - hey presto a bunch of connectors!
Test the opposite side of the red/white + red/black wires coming from fuse panel with your tester - power should go through the connector OK. At this point the wires develop into this flat strap - top wire is brown and the rest are black. The one that interest us are the bottom and the second from bottom and third from bottom black wires.
If power here then reassemble.
Sitting in the rear passenger seat remove the two rear window sunscreens - careful the screws do not fallout an disappear into the footwell! - the whole panel is then held in by black snap-in plugs - start at one corner and pull sharply feeling your way around the panel. They will all pop off easily. This will then leave you with the panel hanging off the roof by the interior light wires - carefully you can manipulate the whole interior light unit through the cut out in the panel and then put panel out of your way leaving light unit hanging only.
Sit back and look at under side of hatch. You can see a connector in a cut out - test power here - select the point where the thick red and thick black wires paired together come out of the connector and test. Test also the other thick red wire coming out of the connector. If no power then you have same problem as me - the flat roof harness is twisted over on itself and the wires have become increasingly pinched with age where they run from the B pillar across the roof lining and then through the plastic shoe which carries then across the hinge into the hatch panel. Eventually they give up the ghost and - no power!. Undoing the plastic shoe (2 small phillips screws) ease the wire strap out to make the next job easier. Check which ones are broke and using small wire splices cut and rejoin the flat wire - to make it less prone to this in the future - be careful - one of these wires is live and feeds the interior light so when you cut either discionnect the earth strap or (easier) pull fuse 24 in the fuse panel. I carefully separated each wire of the flat pack with a blade as far as I could from the base of the plastic shoe back towards the B piller - they then become much more amenable to twisting and arranging so that they do not kink again. Test again and then reassemble.
My car has a sunroof and the mechanism for this is up under the roof lining - I think that the sunroof mechanism contributed to the kinking of the flat wires also.
Anyway fixed and now only have to wait for a typical cold misty morning to check it properly - not a long wait in the UK!
Thanks to DaveW, Jack Riffle and Jerry O for all their help. Hope this helps others mystified by their rear heater either suddenly stopping working or slowly becoming more an more inefficient before stopping all together.
Andy
<img src="graemlins/xyxwave.gif" border="0" alt="[bigbye]" />
Red white and red black wires from "T" coded socket on front lower RHS of fuse panel run along side the outer sill of passenger footwell up into the rear three quarter panel directly to the left of the passenger seat. Under here they connect to another loom which is comprised of one brown wire and 6 black bonded together to form a flat "strap". This runs up the B post across the top of the rear part of the head lining where it then exits over the hinge to the rear hatch in a black plastic shoe and under the head lining panel that runs the full width of the top of the hatch (which also holds the centre rear interior light. There is a connector under here which distributes the power to the light and the rear window heater.
My problem was no power at the rear window heater or the light unit - tested at the fuse panel with a simple bulb tester (For testing purposes - switch the ignition on and turn the rear heater switch to position one only. Test bulb on and then test bulb off).
Mine tested OK so moved on to the connector under the rear 3/4 panel - undo the two upper screws holding panel to roof - one has a coat hanger plastic **** on it. Gently pull the door trim away down the door frame. Take out the rear seat lower squab (this looks cheap and nasty when it is removed - a bit of foam and lots of glue!) - you can then see a small trim screw holding the trim panel which the rear lap belt come through - remove this and gently deform the panel to slip out a metal U clip half way up (holds this panel to 3/4 one). Underneath the area where the screw was you will see another small screw holding the 3/4 panel - undo this. My car has a speaker mounted in the 3/4 panel - it does not look standard (the stereo is not) I took this off also - hey presto a bunch of connectors!
Test the opposite side of the red/white + red/black wires coming from fuse panel with your tester - power should go through the connector OK. At this point the wires develop into this flat strap - top wire is brown and the rest are black. The one that interest us are the bottom and the second from bottom and third from bottom black wires.
If power here then reassemble.
Sitting in the rear passenger seat remove the two rear window sunscreens - careful the screws do not fallout an disappear into the footwell! - the whole panel is then held in by black snap-in plugs - start at one corner and pull sharply feeling your way around the panel. They will all pop off easily. This will then leave you with the panel hanging off the roof by the interior light wires - carefully you can manipulate the whole interior light unit through the cut out in the panel and then put panel out of your way leaving light unit hanging only.
Sit back and look at under side of hatch. You can see a connector in a cut out - test power here - select the point where the thick red and thick black wires paired together come out of the connector and test. Test also the other thick red wire coming out of the connector. If no power then you have same problem as me - the flat roof harness is twisted over on itself and the wires have become increasingly pinched with age where they run from the B pillar across the roof lining and then through the plastic shoe which carries then across the hinge into the hatch panel. Eventually they give up the ghost and - no power!. Undoing the plastic shoe (2 small phillips screws) ease the wire strap out to make the next job easier. Check which ones are broke and using small wire splices cut and rejoin the flat wire - to make it less prone to this in the future - be careful - one of these wires is live and feeds the interior light so when you cut either discionnect the earth strap or (easier) pull fuse 24 in the fuse panel. I carefully separated each wire of the flat pack with a blade as far as I could from the base of the plastic shoe back towards the B piller - they then become much more amenable to twisting and arranging so that they do not kink again. Test again and then reassemble.
My car has a sunroof and the mechanism for this is up under the roof lining - I think that the sunroof mechanism contributed to the kinking of the flat wires also.
Anyway fixed and now only have to wait for a typical cold misty morning to check it properly - not a long wait in the UK!
Thanks to DaveW, Jack Riffle and Jerry O for all their help. Hope this helps others mystified by their rear heater either suddenly stopping working or slowly becoming more an more inefficient before stopping all together.
Andy
<img src="graemlins/xyxwave.gif" border="0" alt="[bigbye]" />