Suppressor Relay XI
05-27-2012, 04:41 PM
#16
Nordschleife Master
Thread Starter
So either there is a fault with the HVAC head unit or its the changes you made. Honestly I'd expect its more likely to be related to the changes you made (but maybe something got damaged).
Try the DEF mode - this is another different way to turn on the AC Clutch relay- does this also drop out the clutch when the light are on?
Does anything else happen when you turn the lights on (distribution flaps change posistion?)
If you can measure the HVAC connector (while connected).
Pin 4 is ground and should stay at 0V wrt a vehicle ground point at all times (this goes to the ground side of the relay coil). Pin 11 is one source that feeds the +ve relay coil (via a diode), Pin 7 is the other source that feeds the +ve relay coil (via a diode). See what is happening on these under these conditions.
Otherwise take out the HVAC head unit dissassemble and test connectivity between Pin 3 (illumination) and the +ve side of the relay coil use diode tester in each direction.
Also do the same between the coil and Pins 7 & 11. Should conduct for these only in one direction when 7 or 11 are more positive.
Alan
Try the DEF mode - this is another different way to turn on the AC Clutch relay- does this also drop out the clutch when the light are on?
Does anything else happen when you turn the lights on (distribution flaps change posistion?)
If you can measure the HVAC connector (while connected).
Pin 4 is ground and should stay at 0V wrt a vehicle ground point at all times (this goes to the ground side of the relay coil). Pin 11 is one source that feeds the +ve relay coil (via a diode), Pin 7 is the other source that feeds the +ve relay coil (via a diode). See what is happening on these under these conditions.
Otherwise take out the HVAC head unit dissassemble and test connectivity between Pin 3 (illumination) and the +ve side of the relay coil use diode tester in each direction.
Also do the same between the coil and Pins 7 & 11. Should conduct for these only in one direction when 7 or 11 are more positive.
Alan
I began by taking measurements from Pins 4, 7, and 11. When I got the (surprising) results I did, I decided to measure every Pin in the HVAC connector.
The measurements were taken with light switch Off, light switch ON fogs OFF, and light switch ON fogs ON
Results:
Light switch OFF - Pins 1 - 9 0.0v, Pin 10 13.7v, Pin 11 & 12 0.0v, Pin 14 0.0v, Pins 13 & 15 0.1v
Light switch ON fogs OFF - Pins 1,2,4,6,8,9,11,12,14 0.0v Pin 10 13.5v, Pin 3 12.4v, Pins 5 & 7 0.4v, Pins 13 & 15 0.1v
Light switch ON fogs ON - the same os 'fogs OFF' with the non significant difference at Pin 11 at 0.2v
So my power to the HVAC board is from the switched outlet of Relay IV (the X) ?
05-28-2012, 11:52 AM
#17
Nordschleife Master
Thread Starter
Bump for Alan.
Alan,
I began by taking measurements from Pins 4, 7, and 11. When I got the (surprising) results I did, I decided to measure every Pin in the HVAC connector.
The measurements were taken with light switch Off, light switch ON fogs OFF, and light switch ON fogs ON
Results:
Light switch OFF - Pins 1 - 9 0.0v, Pin 10 13.7v, Pin 11 & 12 0.0v, Pin 14 0.0v, Pins 13 & 15 0.1v
Light switch ON fogs OFF - Pins 1,2,4,6,8,9,11,12,14 0.0v Pin 10 13.5v, Pin 3 12.4v, Pins 5 & 7 0.4v, Pins 13 & 15 0.1v
Light switch ON fogs ON - the same os 'fogs OFF' with the non significant difference at Pin 11 at 0.2v
So my power to the HVAC board is from the switched outlet of Relay IV (the X) ?
I began by taking measurements from Pins 4, 7, and 11. When I got the (surprising) results I did, I decided to measure every Pin in the HVAC connector.
The measurements were taken with light switch Off, light switch ON fogs OFF, and light switch ON fogs ON
Results:
Light switch OFF - Pins 1 - 9 0.0v, Pin 10 13.7v, Pin 11 & 12 0.0v, Pin 14 0.0v, Pins 13 & 15 0.1v
Light switch ON fogs OFF - Pins 1,2,4,6,8,9,11,12,14 0.0v Pin 10 13.5v, Pin 3 12.4v, Pins 5 & 7 0.4v, Pins 13 & 15 0.1v
Light switch ON fogs ON - the same os 'fogs OFF' with the non significant difference at Pin 11 at 0.2v
So my power to the HVAC board is from the switched outlet of Relay IV (the X) ?
05-28-2012, 01:17 PM
#20
Nordschleife Master
Thread Starter
05-28-2012, 01:53 PM
#21
Three Wheelin'
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I'd say there's a problem in the head unit, then. From what I can see in the wiring diagram, an internal switch should be providing power from pin 10 to pin 15, when Def is engaged. Once you have power on 15, that should engage relay X, which then provides power to pin 5.
Anyway, there have been reports before of people finding burned up traces inside their head units due to something else getting shorted. I would pull the head unit, open it, set it to Def, and then see (with a meter) why current doesn't seem to be flowing between 5 and 15.
Anyway, there have been reports before of people finding burned up traces inside their head units due to something else getting shorted. I would pull the head unit, open it, set it to Def, and then see (with a meter) why current doesn't seem to be flowing between 5 and 15.
05-28-2012, 02:07 PM
#22
Nordschleife Master
Thread Starter
I'd say there's a problem in the head unit, then. From what I can see in the wiring diagram, an internal switch should be providing power from pin 10 to pin 15, when Def is engaged. Once you have power on 15, that should engage relay X, which then provides power to pin 5.
Anyway, there have been reports before of people finding burned up traces inside their head units due to something else getting shorted. I would pull the head unit, open it, set it to Def, and then see (with a meter) why current doesn't seem to be flowing between 5 and 15.
Anyway, there have been reports before of people finding burned up traces inside their head units due to something else getting shorted. I would pull the head unit, open it, set it to Def, and then see (with a meter) why current doesn't seem to be flowing between 5 and 15.
I think what I am going to do is get a 'new' (rebuilt) controller unit. I don't feel comfortable doing isolated AC relay work/upgrades with the existing HVAC controller board.
05-28-2012, 02:56 PM
#23
Nordschleife Master
Thread Starter
Just mulling over it after a cup of coffee, I have to say it is a shame with the nice LED work I did on the controller illumination. I will still hold me breath, and cross my fingers when after I turn the headlight switch on !
Thanks Alan, dr bob, and everyone that contributed over time on this post and my 'Tricky AC problem' post.
Craig
Thanks Alan, dr bob, and everyone that contributed over time on this post and my 'Tricky AC problem' post.
Craig
07-08-2012, 12:06 PM
#24
Nordschleife Master
Thread Starter
Continuing with the AC - Light Switch Illumination Saga.
I had an interesting finding the other day. Hit a bump and the central console and pod switch illumination failed (except headlight switch). Dash lights and ash tray remained illuminated however. Found the cause to be a Black/Blue to the console with a suboptimal splice (prior to my ownership). Repaired this. Also checked all grounds at MP IV and MP V. No feedback loops. This was all posted.
The interesting finding was that with the defect intact (lights to HVAC controller faulted), the AC compressor would engage with the Headlight Switch turned on. After the repair of the Black/Blue it went back to its normally abnormal state.
I got to thinking, what if I isolated the illumination to the HVAC controller - meaning fed power from Black/Blue system and separate ground taking it off the HVAC controller board at Pin 3 and Pin 4. On review of the WD, there is a tie in to a diode on the ground side of the controller illumination - what this does I do not know. Well when I did this, it still functions with the Lights on defect.
I have two questions:
1. What occurs on the ground side of the illumination with this diode and its connections ?
2. Some have suggested the relay on the controller is the fault. Why then would it work perfectly with the Lights off ? My real question here is would you change out the relay via a method like Dwayne's ? I am a little leery in doing this for I still think the defect is on the board - I think I would then have the same defect with a heavier duty relay.
Please Guys... your wisdom.
Thanks
Craig
I had an interesting finding the other day. Hit a bump and the central console and pod switch illumination failed (except headlight switch). Dash lights and ash tray remained illuminated however. Found the cause to be a Black/Blue to the console with a suboptimal splice (prior to my ownership). Repaired this. Also checked all grounds at MP IV and MP V. No feedback loops. This was all posted.
The interesting finding was that with the defect intact (lights to HVAC controller faulted), the AC compressor would engage with the Headlight Switch turned on. After the repair of the Black/Blue it went back to its normally abnormal state.
I got to thinking, what if I isolated the illumination to the HVAC controller - meaning fed power from Black/Blue system and separate ground taking it off the HVAC controller board at Pin 3 and Pin 4. On review of the WD, there is a tie in to a diode on the ground side of the controller illumination - what this does I do not know. Well when I did this, it still functions with the Lights on defect.
I have two questions:
1. What occurs on the ground side of the illumination with this diode and its connections ?
2. Some have suggested the relay on the controller is the fault. Why then would it work perfectly with the Lights off ? My real question here is would you change out the relay via a method like Dwayne's ? I am a little leery in doing this for I still think the defect is on the board - I think I would then have the same defect with a heavier duty relay.
Please Guys... your wisdom.
Thanks
Craig
Last edited by MainePorsche; 07-08-2012 at 05:55 PM.
07-08-2012, 12:22 PM
#25
Team Owner
pull the head unit and inspect it for burned traces and add the external relay.
07-08-2012, 01:09 PM
#26
Three Wheelin'
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It doesn't have to be external.
And, IMO, fixing it with a new internal relay makes it less likely there will be future problems when removing the head unit or opening the console (by you or a future owner).
And, IMO, fixing it with a new internal relay makes it less likely there will be future problems when removing the head unit or opening the console (by you or a future owner).
