dRock's '92-'97 Panther Traction Assist Defeat How-To


On 1992-1997 Crown Victoria, Grand Marquis and Lincoln Town Cars vehicles ordered with ABS include a standard Electronic Traction Assist (ETA) function (excluding Town Car, ETA optional on top of ABS) to aide low speed driving on slippery surfaces.
This feature is controlled completely by the ABS/Module and uses the ABS hydraulic control unit to modulate the brake caliper of the spinning rear wheel in an effort to reduce wheel spin.
Unfortunately, the system isn't very effective (except at making a loud buzzing sound from the front left corner of your car) and offers no means of throttle control / power limiting - even worse Ford decided we didn't have any reason to disable it and neglected to install a disable/defeat switch.Some have actually found it to be more of a hindrance than beneficial when driving in winter conditions, to the point of removing ABS fuses to disable it - but knocking out the ABS along with it.

The following article describes a modification to retrofit a traction control disable switch from a later model panther (or any other switch you desire) into a 1992-1997 to disable the traction assist, but keeping the ABS system otherwise functional for OEM-like operation and appearance.

This mod is actually very simple and easy to perform. I have had it installed on my own car for months without issue.

First you will need some parts;

As most know, the ETA function of the ABS module is disabled whenever the brake pedal is depressed. What we will do is 'fool' the ABS module by providing a switched B+ signal to the brake on/off switch input wire, but isolate it from the rest of the brake lamp circuit using the diode(s) so current won't backflow to the lamps or other devices.

The wiring will be slightly different depending on which switch type/style you choose, so here are a few diagrams to explain the wiring with various configurations;

Using a 2001-2002 Panther Traction Control Switch:

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Using a 2003+ Panther Traction Control Switch:

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Using a 1998-2000 Panther Traction Control disable - or - *any* momentary pushbutton normally open switch:

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Using a toggle switch:

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If you opted to use the 5 independent standard automotive relays instead of the Napa/Echlin AR284 latching, you will need to wire them like this and substitue the assembly in place of the latching relay in diagram above that matches your install:

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And a pinout of the 1995-1997 ABS module, with the pin/wire we will be using highlighted;

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What any of these circuits will do is switch power to the BOO input pin (Light Green wire) of the ABS module, making it think the brakes are engaged, thus disabling the ETA function but leaving the ABS system otherwise operational.
Because this is tricking the ABS module and leaving it powered, in some rare conditions that one or more wheels wheels are moving significantly slower than others WHILE the Trac-disable is engaged, the ABS may think that wheel is about to lock up and will modulate the hydraulic output to that caliper using the HCU. Because of which, I'd only disable trac when you NEED it off, rather than all times.
This is also why I recommend installing a switch like this rather than the 'permanent' ETA disable mod by cutting and putting a jumper between the BOO input and switched ignition feed to ABS.

The latching relay (Napa AR284) is designed to switch between the 56a and 56b poles with a single ground/negative pulse to the relay's "S" pin. This means by depressing the pushbutton once the TRAC disable circuit will engage and remain engaged (Trac OFF) until the pushbutton is depressed again, or the vehicle is restarted.
The ABS module is only using the BOO circuit as a logic input, meaning a (very) low current draw - you can see how thin the BOO wire at the ABS connector is when you snip it. The hot in run power source you choose for your install can be something existing in the car (like at the HVAC or radio connectors) since that is the only thing being powered.
Optionally, an inline fuse can be used on the switched disable output between ABS module and relay (put fuse near relay) so if any shorts develop only the TRAC defeat circuit will be disabled, and not the circuit you are using for hot w/ ignition power. This fuse should be VERY small (<5amp)

The illumination input for the 2001+ switches can be wired to anything nearby your switch location, including the radio wiring, clock, HVAC, rear defrost switch, etc. The wiring color (Orange w/ Black Stripe) is consistent for that illumination circuit throughout the vehicle and for all years.

You can decide for yourself where you want to mount the switch. If you choose the 2001-2002 or 2003+ panther switches for your 1995-1997 CV/GMQ you can use a 2001+ CV/GMQ/MM LH dash trim piece and put it in the factory location. Make sure to get the two cutout version (for cars w/ Trac and adjustable pedals) so you can also mount your 1995-2000 defrost switch in one of the two cutouts (not a direct fit into the new style cutouts (no mounting provisions on back), but can be mod'ed to work) - or also use a 2001+ RH trim piece and defrost switch with the relocated HVAC surround position.
*Note, with either you will have to cut out an opening in the black plastic dash frame to clear the switch as there is not an extra opening for the 01+ locations in either position.

Another nice location; using your existing stock trims, would be to duplicate the 2001+ defrost switch location (left side of HVAC surround trim) but have the switch mounted horizontally instead of vertical. Again, the plastic dash frame will have to be cutout for the switch to pass through.

I retrofitted a center console and shifter to my car a few years ago, and the trim piece surrounding the shifter was an ideal location for me;

The relay(s) should be mounted close to the trac switch to minimize wiring runs. You will still need to run one wire into the engine compartment and to the DOWNSTREAM side of the diode(s) which will be wired inline of the existing BOO input wire to ABS module.
The diodes and signal wire must be tapped into the harness at the ABS module/connector itself as there are numerous splices in the BOO circuit, and if the tap was made upstream of any of these splices the new trac defeat circuit would also be powering any components coming from that splice.
The airbox assembly will have to be removed for enough room to work on the wiring at the ABS module.

Here are some pictures and more info from my installation:

^^ These are the diodes. Originally I was using two Ford EEC diodes in parallel with spade terminals. That worked fine but I wanted something cleaner and weather proof. So, I took two standard 12v diodes, arranged them in parallel and soldered 1/4" male spade terminals on the leads. I then slid the diodes into a standard ATC weather proof fuse holder to keep them sealed. This also allows you to disable the mod if needed by replacing the diode(s) with a standard fuse and disconnecting the new signal wire and/or switch. I used two diodes for redundancy, just one is sufficient.
The black 'gunk' is liquid electrical tape over the solder joints

The fuse holder came pre-terminated with a wiring pigtail (12 AWG) which was soldered inline of the BOO input wire to ABS module. The THIN orange wire (16AWG) is my signal wire from the latching relay. Since this is low-current only 16awg wire was used. This signal wire must be DOWNSTREAM of the diode(s) (between diode(s) and ABS module itself), that way current can flow from the new switch circuit to the module to disable the ETA - but not backflow to the brake lamps and other BOO circuit components whenever the circuit is engaged.

In order to access / expose the BOO signal wire (LIGHT GREEN) the cap over the back of the ABS connector had to be removed. This is easily done with a flat head screwdriver. The ABS connector is secured to the ABS module using a metric bolt which must be loosened to disconnect it. If I recall correctly this was a 10mm head.

I enlarged the fuse holder's mounting hole so it could be slipped onto the barbed push-rivet on the LH ABS wheel speed sensor wire visible in the picture, securing it to the fender liner.

All of the wiring for this mod is hidden under the airbox and the splices under the connector cap which makes it virtually undetectable. Using split loom encapsulated by electrical tape and discrete routing will make your wiring into the engine compartment appear like a factory harness.

BTW - I *highly* recommend running an extra wire or two into the engine compartment at the same time for any future projects. In fact the orange wire run to the ABS you see in my pictures was an extra wire in that loom which I ran when I installed a VDO Outside temp gauge sensor a few years prior.

Switches installed in extra trim bezel for floor console;

My switch and latching relay harness;

*Note: I did NOT use the NAPA AR284 relay. In fact that is a Lincoln Mark VIII rear defrost switch which I modified to perform the same function. The main difference is in addition to the latching ability my modded defrost switch also has a timer circuit that will automatically unlatch it after 10 minutes.

I used the 4 pin molex PC connector so the trim piece could still be removed if needed. This also allowed this project to be a plug-and-play piggy-back install with the wiring and molex connector configuration I used for my Marauder gauge pod w/ VDO instruments installation.





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Page last updated: 12-06-2008