DIY: Converting 94-00 Style Defroster/Fog Switches to 01+ Style

[95riosnake]

If you have done, or are considering doing a double DIN swap from an 01+ mustang into your 94-00 mustang and want to complete the transformation, you're probably like me and dig the smooth look of the cluster bezel without the eyesore of the rectangular defrost button. Not to mention, having blanks fill the switch holes is just a little disappointing.

 

So I set out to figure out how to make it happen. It's a bit more complicated than just clipping wires and splicing wire A to wire B, but with a bit of basic soldering ability, some patience and this thread you can do it too.

 

The primary issue that complicates matters is the 94-00 style defroster switch uses an internal relay, while the 01+ switch activates an external relay. Since the early cars don't have an external relay, it is necessary to wire it all up to make the newer style switch activate the relay in the 94-00 switch. Here's how you do it.

 

First you will need to get an 01+ defroster switch, the wiring pigtail that plugs into it (mine had evidence of a previous splice, not a big deal though as I'll be soldering to it anyway), and remove your early style switch.

 

 

Start by DISCONNECTING THE BATTERY! then removing the button cover on the 94 switch. Gently pry the side tabs:

 

 

And the top/bottom tabs:

 

 

Once the button cover is removed, you will see a twist-in bulb.

 

 

As you can see, the bulb must be removed in order to remove the button from the housing.

 

 

Unscrew the bulb and remove it to free the white button.

 

 

At the rear of the switch housing you'll find two tabs on the top and two on the bottom, gently pry them to slide the connector and attached circuit board out of the housing.

 

 

 

Next you'll need to remove the connector from the circuit board.

 

 

Look inside the connector and you'll see a clip that engages the pins to hold the connector in place. Pry it up gently

 

 

Then remove it

 

 

 

Now that you have the circuit board freed from its cage, lol, it's time to start the conversion. The existing switch needs to be removed from the board. The three soldering joints circled in red mount the switch and have no electrical connection, and the two circled in blue are the electrical connections. All 5 joints will need to be de-soldered and the switch removed.

 

 

 

Here are the pinout diagrams for the two switches.

 

The joint on the right will need to connect to Pin 1 (Pink/Light Blue wire) on the late model switch pigtail, and the joint on the left will need to connect to Pin 2 on the late model switch pigtail.

 

 

You will need about 42" of wire in 5 colors. The actual colors are up to you, but having 5 different colors will help you keep things straight in your head. I had a bunch of extra wire left over from shortening my Ridetech harness, so I used some of that. It ended up biting me in the ass later on because this 14 gauge wire was so thick I had difficulty getting everything back into the switch housing and had to trim a little more than what I show later in this thread. I recommend using 18 gauge or 16 gauge, but no heavier than 16 gauge. 18 gauge is ideal.

 

 

Solder two wires into the joints from the stock switch. I chose to bridge each one over to one of the mounting joints for a little extra protection against the wire working its way loose over time. (yea yea I know, the soldering could have turned out nicer )

 

 

 

Next, on the other side, you'll need to solder the other 3 wires onto the connector pins. In this pic, the left most pin will connect to Pin 8 (Light Blue/Red wire) on the late model switch pigtail, the second will connect to Pin 4 (Black wire) on the late model switch pigtail, and the pin on the far right will connect to Pin 6 (Brown/Light Blue wire) on the late model switch pigtail.

 

 

Now that the soldering on the circuit board is finished, the switch housing needs some trimming for a couple reasons. One is to let the wires come out of the front of the switch, and the other is to recess the switch enough to allow it to fit behind the new late model cluster bezel. Start by cutting the outlined section off with a Dremel.

 

 

Then another notch will need to be made on the bottom to provide room for the two switch wires to exit.

 

 

 

Slide the circuit board back into the connector.

 

 

Insert the clip to secure them together

 

 

Feed the wires though the switch housing then slide the circuit board back into the channel found inside it, then snap it back together.

 

 

 

Next you'll need to sheathe the wires to protect them and make it easier to feed them through the dash. I chose to use some Tech Flex, but you can also use wire loom or wrap them in electrical tape.

 

 

 

Next you'll need to remove the cluster from your dash. This will give you access to route the new harness to the new switch location.

 

 

Plug the switch into the stock pigtail.

 

 

Then push the switch back into the dash.

 

 

Feed the harness behind the cluster and through the dash to bring it out under the radio.

 

 

A chunk of wood on the console makes a convenient soldering bench

 

 

Solder the wires to the pigtail as outlined in the earlier steps.

 

 

Wrap the soldering joints (optional but it is cleaner and looks better )

 

 

Reinstall your cluster.

 

 

Reconnect the battery, test the switch, smile and pat yourself on the back.

 

 

Now if you're installing a @Carbon Driven cluster bezel like I was, remove the clips from your stock bezel and push them onto the posts found on the back of the new bezel.

 

 

 

Snap the new bezel in, reinstall headlight knob, and slip your gauges in (if using a dual pod version like mine)

 

 

Reinstall radio bezel, connect pigtail to switch and pop it in place.

 

 

Boom.

 

 

Next up is the fog light switch conversion. Rest easy though, this is far simpler to do because both wiring systems use an external relay. That means this is a simple clip and solder operation.

 

First you will need an 01+ fog light switch and pigtail.

 

 

Next you will need to remove the inside of your console under the arm rest (pull up two rubber bumpers on front two corners, then remove screws, then pull upward to unsnap the interior of the console), then pop out your stock fog light switch, unsnap the switch from the pigtail. The 98+ console I have gives you more room to work with, but the 94-97 still allows you to just pull the pigtail up through the hole where the fog switch was.

 

 

Strip the ends of the wires on your 01+ pigtail and solder on 30" of wire. Once again, the wire color is up to you. The gauge isn't as critical this time, but I recommend 14, 16 or 18 gauge.

 

 

Then sheathe the wires for protection and ease of routing

 

 

Here's a comparison of the wiring diagrams for both switches. I have outlined the important part of the 94-00 diagram in red.

 

As you can see, the connections that need to be made are as follows:

 

(94) Yellow > (01) White/Black

(94) Red/Black > (01) Brown

(94) Black > (01) Black

(94) Light Blue/Red > (01) Light Blue/Red

 

Route your new harness from the dash back to the console switch location.

 

 

Set up your temporary soldering bench again...

 

 

Solder and heat shrink the wires.

 

 

Reconnect your battery, plug the pigtail into the back of the new switch, press it and smile.

 

 

Reinstall the console interior and dash bezels and you're done!

 

 

[deceptive gt]

Awesome! Now to have a little wiring fun!

[Yeahloh95]

thanks for the great write up dan

[Sleeperstang1994]

well done. looks great!

[Blackmage]

nice write up dan! Howd you know where to tap into on the circuit board?    Also, have a blank over the hole is not disappointing, just means you don't have the unnecessary parts and you're faster. yea.. ill keep telling myself that lol

[95riosnake]

nice write up dan! Howd you know where to tap into on the circuit board?    Also, have a blank over the hole is not disappointing, just means you don't have the unnecessary parts and you're faster. yea.. ill keep telling myself that lol

 

I found a thread where a guy did it, but all he showed was connecting the two wires where the switch was, everything else was left up to you like what pins connect to what pins, how to open the older switch housing, what to trim, etc. Took me a while to figure out what to do other than those two wires. Due to my frustration in doing so, I decided it was time for someone to write up a proper DIY

 

The blanks disappointed me because if I don't have buttons there, I don't want anything there lol. But since I have a beautiful Carbon Driven piece, shaving them wasn't really an option.

[Psychorugby]

The blanks disappointed me because if I don't have buttons there, I don't want anything there lol. But since I have a beautiful Carbon Driven piece, shaving them wasn't really an option.

 

If I ever get there... I want to wire up the battery, fuel pump, and fans there.  Race car shit.

[Det_Riot]

If I ever get there... I want to wire up the nitrous, electric supercharger, and hydraulics. Race car shit.

Fixed ;-)

[Psychorugby]

Fixed ;-)

 

oooh hydraulics... three wheel motion!

[Det_Riot]

oooh hydraulics... three wheel motion!

Cuts down on that friction factor when you're launching!

[Tabres]

That's really cool.  Love stuff like this.

[Dysturbed87]

That's really cool. Love stuff like this.

I agree. I may need to do this. Now just waiting for the fog light switch write up

[95riosnake]

The fog switch is supposed to be delivered today, so I'll knock that out this weekend and have the write up done soon after. The fog switch will be MUCH simpler than the defrost was.

[Carbon Driven]

Absolutely great write up Dan!! 

 

Say I wonder if you could create the harness and converted defroster plug as a complete product to sell? Seems like all you need is a relay, wires and couple plugs? May make a nice and simple conversion for others to just buy from you all as a complete package?

[95riosnake]

Absolutely great write up Dan!! 

 

Say I wonder if you could create the harness and converted defroster plug as a complete product to sell? Seems like all you need is a relay, wires and couple plugs? May make a nice and simple conversion for others to just buy from you all as a complete package?

 

Possibly, the hardest thing to find is the pigtail that plugs into the back of the new defroster switch. I bought mine from a guy parting out a car. You can buy the switches all day long on eBay but they never have the pigtails with them.

 

You may be onto something though, if I can source the parts it might be doable. It probably won't be the cheapest thing once I add up the cost of the parts and add in a little compensation for my time lol. I'll have to look into it

[Carbon Driven]

Possibly, the hardest thing to find is the pigtail that plugs into the back of the new defroster switch. I bought mine from a guy parting out a car. You can buy the switches all day long on eBay but they never have the pigtails with them.

 

You may be onto something though, if I can source the parts it might be doable. It probably won't be the cheapest thing once I add up the cost of the parts and add in a little compensation for my time lol. I'll have to look into it

 

My thought is that it may be a bit much for most to do but if its just a plug n play harness like all the guys have for the sequential taillights it could be a hit.

 

I think you could have them send in their defroster switch as a core trade for the converted one. Then you dont have to buy that one.

 

Maybe with the new defroster switch, you "could" solder directly on to the pins (?) and have a short lead of wires go to your own 2 part connector plug so they can remove the radio bezel and unplug all their wires still. No need to source the oem connector pigtail that way

 

What do you think?

[95riosnake]

My thought is that it may be a bit much for most to do but if its just a plug n play harness like all the guys have for the sequential taillights it could be a hit.

 

I think you could have them send in their defroster switch as a core trade for the converted one. Then you dont have to buy that one.

 

Maybe with the new defroster switch, you "could" solder directly on to the pins (?) and have a short lead of wires go to your own 2 part connector plug so they can remove the radio bezel and unplug all their wires still. No need to source the oem connector pigtail that way

 

What do you think?

 

Yea a plug and play would be a nice kit, and the core option would work for getting the 94-style switches. If I skipped the OEM pigtails I'd probably have to go with a 5 pin connector like a weatherpak or similar, that would probably be almost the same cost as the pigtails, although more readily available. I'll have to sit down and work out the overhead of putting the kits together vs. what I'd make in profit and see if it's worth doing. At the moment I get maybe a few hours a week to work on my car so it would have to make sense financially to do it.

[Carbon Driven]

I would think $100+ easy for it with the consideration of all switches and wiring etc comes with it as a complete plug n play deal and send in oem defroster switch. Dont even have them take it apart

Time is money and they are saving that plus no headaches of figuring it all out etc or sourcing the switches etc

[95riosnake]

I would think $100+ easy for it with the consideration of all switches and wiring etc comes with it as a complete plug n play deal and send in oem defroster switch. Dont even have them take it apart

Time is money and they are saving that plus no headaches of figuring it all out etc or sourcing the switches etc

 

Very true!

[Steve@CJPP]

hope your fog light switch actually lights up because mine is factory wired and once I did the cobra bumper/fog I bought 2 switches and neither light up 

[95riosnake]

hope your fog light switch actually lights up because mine is factory wired and once I did the cobra bumper/fog I bought 2 switches and neither light up 

 

We shall see, I don't see any reason it wouldn't. My factory switch in the console lights up, and the same current will be fed to the new switch. Unless the bulb in the switch is burnt out it should light up no problem.

[Steve@CJPP]

We shall see, I don't see any reason it wouldn't. My factory switch in the console lights up, and the same current will be fed to the new switch. Unless the bulb in the switch is burnt out it should light up no problem.

I was hoping it was a bulb burnt out but back to back switches lead me to believe otherwise.  Of course yours will work though lol.

[95riosnake]

Fog light switch conversion instructions added

[Carbon Driven]

Fog light switch conversion instructions added

Great job Dan!

[Carbon Driven]

@1SlammedGT for your buttons

[deceptive gt]

How hard would it be to depin and repin the connector for the foglight to make it look even more stock?

[95riosnake]

How hard would it be to depin and repin the connector for the foglight to make it look even more stock?

 

I'm sure it can be done, assuming the pins are the same type. If not, you'd need the pins and the appropriate crimper. I didn't bother since the wiring I did is all hidden in the console anyway.

[RideTech_Ryan]

Great how to Dan.  Wish you guys had S197s.  There are not many forums like this one where everyone is actually out to help out the next guy.

[Carbon Driven]

Great how to Dan.  Wish you guys had S197s.  There are not many forums like this one where everyone is actually out to help out the next guy.

I haz one. What did you need?

[95riosnake]

Great how to Dan.  Wish you guys had S197s.  There are not many forums like this one where everyone is actually out to help out the next guy.

 

Thanks Ryan! I feel obliged to share and help keep the knowledge base for these older cars growing

[RideTech_Ryan]

I haz one. What did you need?

I dont need anything specific.  Just wish there was an s197 group like this group.  You could give me the motor out of the GT500 lol

Thanks Ryan! I feel obliged to share and help keep the knowledge base for these older cars growing

Keep the info coming.  I dont have an SN but I love to read stuff like this.  Im a gear head so learning something new is never a bad thing.  You never know when it might come in handy.