So I did the cobra cluster swap and ran into an issue

[Nightmare]

Ok, a little background. I have a 2004 Mustang Gt. I just swapped in a cluster from a 99 cobra and I had the pats system reprogrammed. Th ecluster works great, however one issue did surface. The rear defrost comes on and stays on, will not turn off. I looked at the diagrams for the wiring and noticed that on both the 99 and on the 04 they are grounded to the cluster, however it makes no sence to me why I would be having this issue. Put back in the oem cluster and the rear defrost operates like it should. For the time being I have the rear defrost relay disconnected, however I would eventually like to have the defroster available if I need to use it.....Any ideas on this or has anyone ever experienced this who has done the same swap? I know that they moved the defrost button from below the headlight switch to below the radio, but I didnt notice any differences in the diagram..........

 

[ttocs]

after a quick search for "99 mustang defroster schematic"

one of the topics that came up from a different forum and explains it a little

your problem is in the 99 mustang they used a smart rear window defrost switch that did not feed into the instrument cluster. in the 2003 they used a basic switch to "tell" the instrument cluster module to activate the rear window defrost relay. in the 2003 the only thing that is the same is the ilum. all the other wiring and what part controls the system is different

I assume you are using the 99 cluster in your car? it will be way to complicated if not impossible to make the 2003 cluster work in your car. and it will be kind of complex to make the 2003 switch work with the 99. you might have to make the 2003 switch activate the 99 switch that will be hidden in the console area.

and you can't just "tap" into the same colored wires on the 99 harness. even if it went to the right pin in the cluster, the 99 cluster will not have the logic built in to control the rear window defroster.

if i was you i would hide the 99 switch inside the console and use the 99 switch. leave the 2003 switch wired to light up and not do anything.

 

[ttocs]

http://www.stangnet.com/mustang-forums/threads/rear-window-defroster-help.614380/

 

[Nightmare]

after a quick search for "99 mustang defroster schematic"

one of the topics that came up from a different forum and explains it a little

your problem is in the 99 mustang they used a smart rear window defrost switch that did not feed into the instrument cluster. in the 2003 they used a basic switch to "tell" the instrument cluster module to activate the rear window defrost relay. in the 2003 the only thing that is the same is the ilum. all the other wiring and what part controls the system is different

I assume you are using the 99 cluster in your car? it will be way to complicated if not impossible to make the 2003 cluster work in your car. and it will be kind of complex to make the 2003 switch work with the 99. you might have to make the 2003 switch activate the 99 switch that will be hidden in the console area.

and you can't just "tap" into the same colored wires on the 99 harness. even if it went to the right pin in the cluster, the 99 cluster will not have the logic built in to control the rear window defroster.

if i was you i would hide the 99 switch inside the console and use the 99 switch. leave the 2003 switch wired to light up and not do anything.

Yes, I am using the 99 Cobra cluster and not the 03/04 cluster......my issue is not that it wont turn on, but stays on all the friggin time, even if the ignition is off....I am thinking that it is on the same lines......one of the techs and I are going to see if there is something in the pats/cluster programming that can be adjusted........

I will say I did get a little confused untill I read that thread why you keept saying 03.....lol

 

[chris91]

Damn well now I know I wont be able to wire up the new 01+ switch to work in my 99. Means I bought the cluster bezel piece for nothin... Oh well..

 

[Nightmare]

Damn well now I know I wont be able to wire up the new 01+ switch to work in my 99. Means I bought the cluster bezel piece for nothin... Oh well..

Make the hole a little bigger and put a gauge in there or a toggle switch for something in there. All is not lost......

Side note, working at a Ford dealership has its advantages, I can always swap and reprogram my pats when ever I think I might need the rear defroster.

 

[ttocs]

this one at the bottom seems to have the same problem and fixed it.

http://www.buckeyestangs.com/vb/showthread.php?27929-Rear-window-defroster-wiring-diagram

 

[chris91]

Ill just find another dummy cover like I have for the T/C, screw messing with it. lol

 

[ttocs]

you/we can wire a relay to make it work I think. But you will need to figure out the pin-out of the switch using your continuity meter again. Take it out of the dash, and simply pick two pins on the bottom of the switch an probe them. If it doesn't beep then push the button and see if that makes it beep. If it still does nothing then try two more pins with the same sequence. What we are looking for is two pins that are common/connected when the switch is on as one we will wire up with power input and the other we wire out for the defroster power. It shouldn't matter which way is in/out either unless the bulb is somehow directional then it might light up. When you find the pins that are common with the switch mark them somehow or write it down to remember. Nest we need to figure out which wire powers the bulb inside. Now one of the pins you just probed, should be common with the light when it is on so now flip your meter to read resistance and start probing pins again till you find one that shows some kind of resistance on it. No I do not know what the reading will be but all the others should show as an open circuit, 0 ohms or else will show some kind of resistance.

 

[Nightmare]

this one at the bottom seems to have the same problem and fixed it.

http://www.buckeyestangs.com/vb/showthread.php?27929-Rear-window-defroster-wiring-diagram

Once again, that is the reverse.......My switch works with the Factory 04 Cluster, and turns on and stays on with the 99 cluster the moment you plug it in to the harness, even with the ignition off and no power going to the accessories. Only way to turn it off at this time is to unplug the defroster switch (not an option when driving, and I really dont like having a hole with a plug hanging out) or just unplug the relay all together.

 

[ttocs]

yes it is the opposite of yours but it still tells what the differences where and how he fixed it. All you need to do is the opposite.

How many pins are on the back of the switch? 3-4?

 

[Nightmare]

yes it is the opposite of yours but it still tells what the differences where and how he fixed it. All you need to do is the opposite.

How many pins are on the back of the switch? 3-4?

I would have to double check, however I am thinking 4.

 

[ttocs]

do you know if those buttons are back-lit ? Does it light up when you push it on and/or does It light up with the parking/headlights? Two of those pins are for switching the power on/off with the switch to the defroster, and I am willing to bet that the last two pins are for lighting. First test for continuity of the pins with the switch both pushed on and off. After that switch to resistance and measure the other two pins. More then likely these are just ground wires that feed the lighting inside the switch, which takes + voltage from the power input on the other two pins we tested for continuity the first time. When you go to test this one on resistance try measuring from one of the pins you identified in the first test and either of the remaining two pins. IF it doesn't show anything then try pushing the button again. Finally the last pin I would suspect is for the dimmer lights that come on with your parking lights. It will not need the switch to be on so you should be able to just try the last pin and again the pin that goes out from the switch to power the defroster.

 

[chris91]

There are 5 pins on the back on the 01+ button. But same with the Fog light button and only 4 wires go to it.

They light up when you turn your running lights on. They also have a little light that lights up when pushed.

 

[ttocs]

ah 5 pins is different. With one not being used sounds like a relay that they are only using the normally open contacts.

just curious does the window actually get warm/hot or is it just the light that is on? Give me a few mins and see what I can find.

 

[chris91]

I havent even started messing with mine yet. I do have my fog button hooked up though so thats how I know about the lights.

 

[ttocs]

does the hrns look lke this on the switch or on the hrns in the car?

 

[ttocs]

http://www.bing.com/images/search?q...96770A7666001FFDAF8FFA1640D4B&selectedIndex=0

 

[Nightmare]

ah 5 pins is different. With one not being used sounds like a relay that they are only using the normally open contacts.

just curious does the window actually get warm/hot or is it just the light that is on? Give me a few mins and see what I can find.

Yes it does, even with the ignition off. My switch is different than the 99 switch......the one you posted up is the dash mounted switch (under the headlights) and not the center stack location.

 

[ttocs]

Yes it does, even with the ignition off. My switch is different than the 99 switch......the one you posted up is the dash mounted switch (under the headlights) and not the center stack location.

Ok so we need either the pin out of the 04 switch or the color code for the wire going to it. Let me see if I can dig that up but two eyes are better then one do as many random searches as you can for"04 mustang GT defroster schematic" try cobra too.. I use bing myself so maybe if you try google we can find it quicker