Alan

What makes the pod think its in night time mode is the power to this circuit.
Thats why it goes back to daylight mode when the fuse blows. It actually connects to the pod in 2 places before the rheostat (to tell it what mode as above) - on Pod plug 1 (pin2) and after the rheostat to actually illuminate the pod on pod Plug 4 (pin 14) but via an external (to the pod board) extra series resistor for the actual pod lights.

I think your rheotsat is messing with your head... it is broken - when it doesn't cause the fuse to blow it is open circuit because it has burned out due to over current - when it does connect the fuse blows... for trouble shooting remove it and short the 2 pins with a jumper - yes the fuse will blow all the time - till you find the source of the problem. Think of your rheostat as acting like a switch - with the switch off - you have a good fuse but no lights and no chance to ever find the problem... get rid of it.. In fact test it with an ohmmeter - you will see what I mean...

So summarizing what you say above. None of the nightime dash lights ever work.
The only time the fuse doesn't blow with the lights on is if the rheostat is in its little dead zone... right?

The most likely scenarios are: its something in the pod OR its something in the console. If the pod is all back together - jumper the rheostat as above and disconnect EVERTHING in the console as prev post. Why? just because its the easiest to do. If that doesn't work you have to take the pod back out for the other tests.

Alan

RyanPerrella

OK time for an update, and i think i now know what the problem is.

As you know the lights in the GT fail to turn on. The fuse blows, the lights dont work, and when i connect the dimmer switch i noticed it gets very hot when the lights are on.

NOW the kicker!

I finally got the S4 back together. I had pulled the interior, cleaned it up and reinstalled. While i was messing with that i send the AC head unit to Doc Mirror to get the large relay installed so that i could get the AC to work. (Wasnt previously) The car was also apart as i had a timing belt light due to a broken electrical contact which i have now fixed as well as readjusted the belt tension, yada yada, WELL tonight i just fired it up to get it going. NOTE, i never had any issues with the dash illumination in this car. (S4)

SO

Now that i start it for the first time in 2 months, i have it running now with fresh oil and put in new coolant. Being that its night time i turn the lights on as i plan on pulling it out of the garage. So as its idling i am going to put the heater on full blast to fully circulate the coolant

WELL

As soon as i hit the fan speed **** from 0 to 1 or 4, BAM, i notice something change.......the damn lights go out! ****!

Anyway i dont pay much attention to this and back the car up, headlights on, just idling in the driveway while i start the GT and put it in the garage.

When i come back to the S4 after 1-2 minutes i get in to reposition the car in the driveway and see smoke coming from the left side of the pod! It looks like the things about to go up any moment! I quickly move the car into a parking position and kill it. I disconnect the battery and think i am done for! I am imagining burnt wires and am expecting the entire dash to go up in flames!

I relax for a minute, and pull the steering wheel thinking i need to tear the pod apart as quickly as possible to get air to this and see whats going on. Well i start to pull the headlamp switch and i see this grey residue. I assume its remnants of the electrical smoke. Pull that, then i pull the fog lamp switch and the zero reset switch and see they all have this smoke. Makes sense this is the side the smoke came from. But as i see it on the lowest switch i realize that something below that was smoking.......the damn dimmer!

So i pull the lower cover off from under the pod and pop the dimmer out and this is what i find (ITS MELTED!)

So now i have a dimmer thats getting way to hot to the point it nearly puts the car up in flames.

So now i have to ask myself, WTF happened to the AC head unit? Thats the only thing thats common between the two cars..... I need to hear from Doc but could some part of the relay be giving the lights too much juice?

Whats my next step?

Good news out of all this is that i think i have located the source of the problems, now what do i do to correct it.

DOC, WHERE ARE YOU!

Alan

Well the head unit is illuminated via pin 3 - this connects directly to the variable illumination. So remove the head unit & test the resistance to ground on that pin on the head unit - it should probably be approx 10 ohms - if you can open it up and remove the bulb it should then be open circuit... I supect it is not...

Did you do relay surgery on this one? any other mods...

Alan

RyanPerrella

you may have to talk me through this one....

pin 3? I know the head unit has 2 electrical connections right next to each other, is pin 3 one of those on one of the 2 connections? Sorry electronics are not my forte.

Could something happen in the HU relay where the power for all the interior illumination goes through and if that "thing" ceases to work it kills all the lights?

Just to reiterate, the dash was light up fine, when i went to touch the fan control it immediately went dark.

I think i will do the following and see if i can get any illumination.

1) disconnect head unit completely (but if i do this would i then be breaking the circuit and again no lights will come on?)

2) check fuse #9 and replace.

3) replace dimer switch

Try and turn the lights on and see if i get anything in the dash to come on

Alan

Ryan - you ask for help....

I tell you what to do...

You propose to do something different...

I may just give up...

Please - do as I say - BEFORE - you do something else... I actually do have an idea what I am talking about...

The only thing that is supposed to be connected to the variable illumination is the bulb in the head unit... obviously if it causes an issue like this its likely actually connected to something else also.... thats why I want you to test it. The illumination of the pod does not depend on the head unit - you can disconnect it and see that the pod works OK - however it won't until you replace or jumper out the rheostat which is now burned out like the last one....

To me there is absolutely no point replacing these parts until you identify and fix the problem - unless you just like the smell of the smoke they give off...

The blower speed **** should not be connected to the illumination... but maybe for some reason it is...

Anyway the connector to check Pin 3 on is the 15 pin large connector check the HVAC head unit side.

Again has anyone played with this head unit in any way (repairs of any kind)?

Alan

RyanPerrella

ok Alan, i will do as you say 15 pin connector, pin 3

Both these head units were sent to Doc Mirror to have the relay's replaced where there is not the "tail" and relay attached to both of them.

I suspect something in that wiring is the issue.

I will do the test in the morning. The tool to test is just a simple multi meter correct?

Alan

Yes multi meter on ohms range...

Alan

RyanPerrella

Ok, so to do this test i have a couple questions.

Your instructions say to remove the HU, and test resistance to ground on pin 3. Ok, when i am testing does the multimeter provide some power for this, because obviously the HU wont have any power from the car? I have a really basic multimeter and i'm not sure thats what i need, so i may go pick one up where i can test ohms (thats resistance right, :-))

Sorry Alan, i am really in preschool when it comes to wiring and electronic testing. If you can give me a step by step that would be great. Unfortnately "test pin 3" is to broad an instruction for me, i dont know what i need to do to accomplish that. Perhaps you can clarify?

Alan

As per this message - BTW Ground is pin 4

RyanPerrella

Allright well i finally got around to putting a multi meter on this thing.

As i am new to this i am posting to make sure i am testing this correctly. As i understand it i would hook up the multi meter ground wire to pin 4, and the red positive to pin 3. I am just not sure what my range should be for Ohms so i posted a picture of my reading for you to see. I can obviously retest if the settings are incorrect but as i understand it it, I believe i have it set correctly.

You mentioned i should get 10 ohms, but at "20M" i get 0, which i believe means that there is a short circuit. [EDIT: now testing at "200" I get 14.2, see picture]

Note, the picture taken was not totally accurate as the test needles slid off when taking the pic. The pic is only a representation of the general area of where i tested. I also took a pic of the meter "on hold" showing the short circuit and showing where the meter was set at "20M".

I just set the ohm dial to "200" and get a reading of 14.2-14.4 (it fluctuates as i cant keep the needles still for long)<<<<<<I BELIEVE THIS IS THE CORRECT SETTING. So this is 14 which is higher then 10, so what does that mean?

RyanPerrella

Bump

When i am supposed to get 10 ohm and end up with 14, what does that mean?

Alan

14 is also OK - the bulb filament resistance when cold is a little hard to predict. When hot it should be much higher but the meter only uses a very small voltage which is why the bulb doesn't illuminate.

The 20M range is for measuring really high resistances - on this scale 14 ohms is so close to zero - thats what it tells you. The 200 range is appropriate and the 14 ohms is reasonable. OK next step test pin 3 against all the other pins except pin 4do any have reading on the 200 range?

Alan

RyanPerrella

OK 1,2,5,6,_, 8,9,10,_,12,13,14,15 show no change when i go to them

pin 7 immediately jumps to 75, then immediately goes to 0. It jumps as soon as i tough it and this behavior is different from what happens when i immediately tough the previous pins.

touching pin 11 also does a similiar thing to pin 7 but its in teh 50-55 range then goes to 1.

Alan

Ryan - tru reversing the DMM probes - what reading do you get now and which probe is/was where (e.g. common terminal (black probe) & V/Ohm/Ma (red probe) to Pin 3

There should not be any connections at less than the 14 ohms for sure...

Alan

RyanPerrella

by reversing you mean putting the red probe on pin 4 (ground) and then going to every oher pin?

I did this (above) and got 0 everytime