Alfa156Melb 9 Report post Posted June 28, 2014 So this is something that's been eating at me for a while.. but diagnosing the problem will be hard at best i think. There seems to be considerable confusion on how the 156 rain sensing wipers work, even amongst specialists... The way the system is meant to work is one click down to where 'intermittent' is on other cars - that's "auto". The wipers will wipe as needed from a random wipe, to full speed depending on the amount of rain. Turn the car off, and back on the system is deactivated until you squirt the washers, or click the stalk up, then back down again to the 'auto' position... easy - and on the JTS, that's worked flawlessly for 8 years of ownership.. Now.. the GTA... it has a rain sensor in the windscreen, it has 'auto' written on the stalk.. it is specified with rain sensor wipers.. but...... When you select the usual 'auto' position, the wipers wipe.. intermittently, exactly like a car without auto wipers... It's as if this car has no auto function at all. Here's where I'm confused.. its either auto or its not.. if the sensory part of the system isnt working, surely the wipers wouldnt wipe at all? So why would it revert to normal intermittent.. a wipe every 5 seconds? So how to fix?? No idea... no idea where to start even. Has anyone else come across this problem? Quote Share this post Link to post Share on other sites
Smaky 73 Report post Posted June 28, 2014 Sounds to me like the GTA has the parts fitted to look like it should have this, but if you lift the scuttle panel is the wiper control ECU fitted or is it swimming in water/crud? Quote Share this post Link to post Share on other sites
Smaky 73 Report post Posted June 28, 2014 And when the auto wipers pack in there is normally NO movement of the wiper at any speed selection. Quote Share this post Link to post Share on other sites
Alfa156Melb 9 Report post Posted June 29, 2014 Sounds to me like the GTA has the parts fitted to look like it should have this, but if you lift the scuttle panel is the wiper control ECU fitted or is it swimming in water/crud? Ironically it's raining, so when it stops I'll check. They are meant to be fitted, as you say, the parts are there, the manual says it should be there.... So the ECU is under the scuttle, I was wondering where that was.. as it's either that or the sensor. Assuming the wirings ok. Quote Share this post Link to post Share on other sites
Alfa156Melb 9 Report post Posted June 29, 2014 And when the auto wipers pack in there is normally NO movement of the wiper at any speed selection. I assumed that, but after posting my question, it occurred to me to check the manual :He He: As it turns out, when the sensor fails, the system reverts to a dumb intermittent function as if there was no auto at all. They work like a conventional system. Quote Share this post Link to post Share on other sites
Smaky 73 Report post Posted June 29, 2014 Check the sensor plug above the interior light then Quote Share this post Link to post Share on other sites
Alfa156Melb 9 Report post Posted July 2, 2014 I've haven't revisited this yet as I've had other things to do.. but tomorrow I'll look at that. Does the sensor simply unplug? Quote Share this post Link to post Share on other sites
Smaky 73 Report post Posted July 2, 2014 Yes. Quote Share this post Link to post Share on other sites
Alfa156Melb 9 Report post Posted July 2, 2014 ok, sounds easy then! Quote Share this post Link to post Share on other sites
Alfa156Melb 9 Report post Posted July 10, 2014 OK so I swapped the rain sensor with a good one today inbetween having my brain sonically rearranged from my stupid car alarm.. But alas.. still not love - wipers work on conventional intermittent, but not auto. Next stop - Wiper ECU? Quote Share this post Link to post Share on other sites
Smaky 73 Report post Posted July 10, 2014 Yes Quote Share this post Link to post Share on other sites
Alfa156Melb 9 Report post Posted July 14, 2014 Bollocks - that'll be expensive.. and difficult to access. Quote Share this post Link to post Share on other sites
Alfa156Melb 9 Report post Posted April 17, 2015 (edited) Check the sensor plug above the interior light then I finally got around to dealing with this.. When i first read your comment it registered to me as the sensor plug in the sensor housing, NOT under the interior light as you suggested.. I should read posts more carefully. I replaced the sensor and chcked its little plug - all good, but no difference. I then replaced the Sensor ECU which came from my JTS - someone crashed into it and wrote it off, so I relieved it of some parts for the GTA, this being one of them.. anyway it didn't make any difference. Well it turns out Smaky, once again you are the guru of all things Alfa's as it was in fact the plug above the interior light that was unplugged. All working now! Wooooooo!!! Edited April 17, 2015 by Alfa156Melb Quote Share this post Link to post Share on other sites
Smaky 73 Report post Posted April 17, 2015 All hail SMAKY !!! Quote Share this post Link to post Share on other sites
smiffy 99 Report post Posted April 18, 2015 NO Quote Share this post Link to post Share on other sites
Smaky 73 Report post Posted April 21, 2015 NED LOVER !!! Quote Share this post Link to post Share on other sites
flyblo5 17 Report post Posted April 25, 2015 Still doesn't answer the REAL question. Why do you need wipers in Oz? Quote Share this post Link to post Share on other sites